Infantile to late adulthood onset facioscapulohumeral dystrophy type 1: a case series

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Infantile to late adulthood onset facioscapulohumeral dystrophy type 1: a case series
WY Leung, MB, BS, MRCPCH1; HM Luk, FHKCPaed, FHKAM (Paediatrics)2; Varut Vardhanabhuti, PhD (UK), FRCR (UK)3; Y Gao, PhD, FHKCP (Neurology), FHKAM (Medicine)4; KF Hui, FHKCP (Neurology), FHKAM (Medicine)5; WY Lau, FHKCP (Neurology), FHKAM (Medicine)6; Terence PH Young, FHKCP (Neurology), FHKAM (Medicine)7; Jessica TC Li, FHKCP (Neurology), FHKAM (Medicine)8; Eva LW Fung, FHKCPaed, FHKAM (Paediatrics)9; Annie TG Chiu, FHKCPaed, FHKAM (Paediatrics)1; Ivan FM Lo, FHKCPaed, FHKAM (Paediatrics)2; Brian HY Chung, FHKAM (Paediatrics), FCCMG (Clinical Genetics, Canada)1; YF Cheung, FHKCP (Neurology), FHKAM (Medicine)8; Sophelia HS Chan, FHKCPaed, FHKAM (Paediatrics)1
1 Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong
2 Clinical Genetic Service, Department of Health, Hong Kong SAR Government, Hong Kong
3 Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong
4 Department of Medicine, Queen Mary Hospital, Hong Kong
5 Department of Medicine and Geriatrics, United Christian Hospital, Hong Kong
6 Department of Medicine and Geriatrics, Kwong Wah Hospital, Hong Kong
7 Department of Medicine and Geriatrics, Ruttonjee & Tang Shiu Kin Hospitals, Hong Kong
8 Department of Medicine, Queen Elizabeth Hospital, Hong Kong
9 Department of Paediatrics, Prince of Wales Hospital, Hong Kong
 
Corresponding author: Dr Sophelia HS Chan (sophehs@hku.hk)
 
 Full paper in PDF
 
Cases
We present the clinical data of eight patients with genetically confirmed facioscapulohumeral muscular dystrophy type 1 (FSHD1) in Hong Kong (Table).
 

Table. Characteristics of the eight patients with facioscapulohumeral muscular dystrophy type 1
 
In June 2015, Patient 1 presented with right ptosis and bilateral sensorineural hearing loss at age 1 year. He had early-onset FSHD1 of the most severe phenotype, with early development of asymmetrical facial and upper limb weakness, significant hearing impairment requiring hearing aids, and an early need for ventilation and feeding support (Fig 1).
 

Figure 1. Patient 1. A 6-year-old boy presenting with early-onset facioscapulohumeral muscular dystrophy type 1. Clinical photographs at age 3 years showing (a) right ptosis and facial weakness, more affected on the right side, and (b) significant bilateral winging of scapula and difficulty raising both arms above shoulder height. The patient stood with hyperlordotic back and had bilateral hearing aids
 
In May 2019, Patient 2 presented with progressive asymmetrical facial weakness with predominant upper limb girdle weakness from age 11 years (Fig 2). Magnetic resonance imaging scan was taken at age 13 years (Fig 3).
 

Figure 2. Patient 2. A 14-year-old boy who first presented with symptoms of facioscapulohumeral muscular dystrophy type 1 from age 11 years. Clinical photographs showing (a) asymmetrical facial weakness more on the left side, and (b, c) marked winging of scapula
 

Figure 3. Patient 2. A 14-year-old boy who first presented with symptoms of facioscapulohumeral muscular dystrophy type 1 from age 11 years. (a-c) Axial T1-weighted and (d-f) short tau inversion recovery (STIR) magnetic resonance imaging scans of the thigh muscles from pelvis to lower thighs taken at age 13 years. (a) Focal fatty infiltration is noted at the left adductor longus, asymmetrically involving the left side (arrow). (b) Focal fatty infiltration is noted involving bilateral adductor longus asymmetrically, more severe on the left side (arrows). (c) More severe fatty infiltration involving posterior compartment of the thighs, particularly semimembranosus bilaterally (arrowheads), and right long head of biceps femoris (arrows) are seen. Discrepancy in size of the biceps femoris with the right side being smaller than left is also noted (arrows). (d) STIR hyperintensity changes are noted involving the right vastus lateralis (arrow). (e) STIR hyperintensity changes are also noted involving the right vastus lateralis (arrow) and to a lesser extent the right semitendinosus and right biceps femoris (arrowhead). (f) STIR hyperintensity changes involving the bilateral biceps femoris (arrowheads) and left vastus medialis (arrow) are also noted
 
In September 2014, Patient 3 presented with upper and lower limb proximal muscle weakness from age 18 years. Magnetic resonance imaging scan was taken at age 23 years (Fig 4).
 

Figure 4. Patient 3. A woman who first presented with symptoms of facioscapulohumeral muscular dystrophy type 1 at age 18 years. (a-c) Axial T1- weighted and (d-f) short tau inversion recovery (STIR) magnetic resonance imaging scans of the thigh muscles from pelvis to upper calves taken at age 23 years. (a) Bilateral T1-weighted hyperintensity indicating fatty infiltration, involving bilateral pectineus muscles (arrows) and gluteus maximus (arrowheads) with more severe involvement on the right side, is noted. (b) Diffuse fatty infiltration of the thigh muscles with atrophy, more severe on the right side, and discrepant circumference on two sides, is noted. There was relative sparing of the left gracilis (arrow) and left biceps femoris (arrowhead), but corresponding muscles on the right side are involved. (c) Atrophy of the left gastrocnemius is more evident compared to the right side. Fatty infiltration with atrophy of the tibialis anterior is noted bilaterally (arrows). (d) STIR hyperintensity changes are seen involving bilateral adductors (arrows). (e) STIR hyperintensity changes are seen involving the left biceps femoris (arrowhead), left gracilis and sartorius (arrow), and right vastus lateralis (dashed arrow) showing an asymmetrical pattern of involvement. (f) STIR hyperintensity changes involving the gastrocnemius bilaterally (arrows)
 
Patients 2 to 8 had insidious onset of muscle weakness during adolescence or adulthood and a slow deterioration of motor function. Asymmetrical muscle involvement was common. Three patients had their lung function assessed of whom two had a restrictive pattern suggestive of expiratory muscle weakness.
 
Patients 1 and 2 were referred to the neuromuscular disorder clinic of the Department of Paediatrics and Adolescent Medicine, The University of Hong Kong for diagnostic examination and testing. Patients 3 to 8 were referred to the Clinical Genetic Service of the Department of Health for genetic testing. All DNA diagnostic tests were performed overseas, either self-financed (Patients 3 to 8 with the genetic testing performed in United Kingdom) or through research collaboration with financial support from the ‘Diagnosis and therapy development of rare neurological diseases and neuromuscular diseases’ fund (Patients 1 and 2, with the genetic testing performed in The Netherlands). For these patients, the diagnosis of FSHD was confirmed by standard genetic testing using Southern blotting and hybridisation with the P13E-11 probe. Restriction enzyme digestion with EcoRI, which recognises the D4Z4 locus on chromosome 4 and 10, was applied. The EcoRI/BlnI digestion further fragments the chromosome 10 array to identify the D4Z4 arrays located on chromosome 4, and the length and number of D4Z4 units were determined.
 
The median age of disease onset was 14 years (range, 1-32). The male: female ratio was 3:1. The median time between onset of symptoms and genetic diagnosis in this cohort was 16 years (range, 2-44). Of the patients who required a walking stick (Patients 5 to 8), the median age at which the need arose was 47.5 years (range, 43-53). Two patients also required a wheelchair for outdoor mobility, from age 49 and 57 years. None of the patients had hearing problems.
 
All eight patients with FSHD1 had a significant contraction—from one to four units—of the D4Z4 repeats. There was no correlation between the number of D4Z4 units and the age of onset or clinical severity; Patients 1 and 7 both had two D4Z4 units, but age of onset differed by 30 years.
 
A positive family history was observed in 38% of our patients. Patients 1 and 4 inherited the autosomal dominant FSHD1 from their mildly symptomatic mother, as confirmed by genetic testing. Patient 6 inherited the condition from his father. Patient 8 passed on FSHD1 to her daughter. Clinical variability and reduced penetrance were evident.
 
Discussion
This is the first case series of genetically confirmed FSHD1 in Hong Kong. Worldwide, FSHD (OMIM No. 158900) is the third most common form of dystrophy, with a prevalence of 1:15000 to 1:20000. It can be classified as type 1 (FSHD1) or type 2 (FSHD2). Most patients with FSHD have FSHD1 (95%) that has autosomal dominant inheritance. Up to one third of cases are caused by de novo mutations.1
 
Typically, FSHD presents during the second or third decade of life as asymmetrical facial weakness followed by muscle weakness around the scapula and upper arms, then truncal and lower extremity weakness. Asymmetrical muscle involvement is typical. In all, 10% to 30% of individuals eventually become non-ambulatory. Around 38% of patients develop a restrictive lung disease pattern, and 1% to 3% eventually require ventilatory support.
 
Early-onset FSHD accounts for 10% of total FSHD. Affected individuals typically present with facial weakness before age 5 years and shoulder girdle weakness before age 10 years. Early-onset FSHD is generally associated with fewer D4Z4 repeats and higher disease severity. Patients often present with global developmental delays, dysarthria, dysphagia, intellectual disabilities, epilepsy, cochlear dysfunction, and retinal vasculopathy.2
 
The genetic mechanisms of FSHD1 are complex (Fig 5). Genetic diagnosis of FSHD1 typically involves the Southern blot technique or the molecular combing technique using fluorescence in situ hybridisation.3 Presently, specific genetic testing for FSHD1 is currently unavailable in the laboratories of the public healthcare system in Hong Kong.
 

Figure 5. Genetic mechanisms in facioscapulohumeral muscular dystrophy (FSHD). In healthy individuals, both copies of 4q35 contain 11 to 100 D4Z4 repeats with normal methylation. In FSHD1, one copy of the 4q35 contains 1-10 D4Z4 repeats with hypomethylation of the D4Z4 repeat array on a permissive 4qA allele. In FSHD1, the open chromatin structure allows transcription of the DUX4 gene from the last D4Z4 repeat into stable mRNA, which translates to toxic DUX4 protein
 
There are several possible reasons for the delay in diagnosis in our cases. First, the lack of patient awareness of an underlying neuromuscular disease at their initial presentation often led to delayed consultation. Second, many doctors are unfamiliar with neuromuscular diseases with consequent delayed referrals. Most importantly, publicly funded genetic diagnostic testing for FSHD1 is currently unavailable. Most patients with a clinical suspicion of FSHD cannot afford expensive overseas genetic testing to confirm their diagnosis. Some patients with FSHD simply do not have the option of diagnosis.
 
Early molecular diagnosis of FSHD is crucial to enable timely assessment and management, including ophthalmic and hearing assessment in early-onset FSHD; regular motor, pulmonary and neuromuscular pain evaluations, referral for an aerobic exercise programme, and surgical scapular fixation if needed. Routine cardiac screening is unnecessary in the absence of cardiac symptoms.4 Early genetic diagnosis can also help to identify other affected or asymptomatic family members. Prenatal diagnosis in pregnancies of affected individuals provides couples with informed choices. Registries for patients with FSHD have been established in different countries to facilitate recruitment for clinical studies and trials.
 
The landscape of clinical trials is promising. A phase 2 study of losmapimod, an oral agent that inhibits and reduces the expression of myotoxic DUX4, is currently underway.5
 
This study increases professional awareness of FSHD and highlights the importance of early recognition and diagnosis for this condition, as well as a current service gap in the genetic diagnosis of FSHD. Establishing a local registry will help recruit patients into clinical trials.
 
Author contributions
Concept or design: SHS Chan, WY Leung, HM Luk, V Vardhanabhuti.
Acquisition of data: All authors.
Analysis or interpretation of data: SHS Chan, WY Leung, HM Luk, V Vardhanabhuti, Yuan Gao.
Drafting of the manuscript: SHS Chan, WY Leung.
Critical revision of the manuscript for important intellectual content: All authors.
 
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Acknowledgement
The authors thank Professor Silvère M van der Maarel and Dr R Lemmers of the Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands, for their expert advice on the diagnosis of facioscapulohumeral dystrophy in the two paediatric patients. The authors also thank Ms Rachel BY Lee for editing the English in a draft of this manuscript.
 
Funding/support
This study was supported by donations from Mrs Yang to the ‘Diagnosis and therapy development of rare neurological diseases and neuromuscular diseases’ fund that provides financial support for overseas genetic testing for patients with facioscapulohumeral muscular dystrophy.
 
Ethics approval
This study was approved by the Hong Kong University Institutional Review Board (Ref: UW_20-405). All patients provided verbal consent to be included in this publication. Two patients (Patients 1 and 2) and their families provided written consent for the publication of clinical photographs.
 
References
1. Sacconi S, Salviati L, Desnuelle C. Facioscapulohumeral muscular dystrophy. Biochim Biophys Acta 2015;1852:607-14.Crossref
2. Mah JK, Chen YW. A pediatric review of facioscapulohumeral muscular dystrophy. J Pediatr Neurol 2018;16:222-31. Crossref
3. Lemmers RJ, O’Shea S, Padberg GW, Lunt PW, van der Maarel SM. Best practice guidelines on genetic diagnostics of Facioscapulohumeral muscular dystrophy: workshop 9th June 2010, LUMC, Leiden, The Netherlands. Neuromuscul Disord 2012;22:463-70. Crossref
4. Tawil R, Kissel JT, Heatwole C, et al. Evidence-based guideline summary: Evaluation, diagnosis, and management of facioscapulohumeral muscular dystrophy: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology and the Practice Issues Review Panel of the American Association of Neuromuscular & Electrodiagnostic Medicine. Neurology 2015;85:357-64. Crossref
5. Michelle Mellion M. Efficacy and safety of losmapimod in subjects with facioscapulohumeral muscular dystrophy (FSHD). Available from: https://clinicaltrials.gov/ct2/show/NCT04003974. Accessed 2 Nov 2020.

Rotational thromboelastometry as a powerful tool to detect hyperfibrinolysis in a bleeding patient: a case report

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Rotational thromboelastometry as a powerful tool to detect hyperfibrinolysis in a bleeding patient: a case report
KM Kwok, FHKCP, FHKAM (Medicine)1; KL Lee, FHKCP, FHKAM (Medicine)1; SY Lam, FHKCP, FHKAM (Medicine)1; T Liong, FHKCP, FHKAM (Medicine)1; HM Wong, FHKCP, FHKAM (Medicine)1; PY Lam, MBBS, MRCP1; Eudora Y Chow, MBBS, FHKAM (Pathology)2; KI Law, FHKCP, FHKAM (Medicine)1
1 Intensive Care Department, United Christian Hospital, Hong Kong
2 Pathology Department, United Christian Hospital, Hong Kong
 
Corresponding author: Dr KM Kwok (kkm394@ha.org.hk)
 
 Full paper in PDF
 
Case report
A 64-year-old man presented to the emergency department with acute onset abdominal pain. His medical history was unremarkable. Initial vital signs showed blood pressure of 87/43 mmHg and pulse rate of 110 beats per minute. His abdomen was distended, with generalised tenderness and guarding. The patient was stabilised with 1 L of crystalloid. Bedside ultrasonographic examination revealed intraperitoneal free fluid. Subsequent computed tomography of the abdomen demonstrated gross haemoperitoneum and multiple hepatic lesions highly suspicious of hepatocellular carcinoma (HCC). Active contrast extravasation was noted at the posterior aspect of segment 2/3 lesion, compatible with the diagnosis of ruptured HCC. The initial haemoglobin level was 8.7 g/dL. Transarterial embolisation was urgently arranged but the patient went into cardiac arrest. Spontaneous circulation returned after 8 minutes of cardiopulmonary resuscitation. Haemoglobin level fell to 5.5 g/dL and platelet count was normal. Prothrombin time and activated partial thromboplastin time were prolonged to 20.3 s and 62.1 s, respectively. International normalised ratio was 1.9. He was transfused with 2 units of pack cells and 4 units of plasma. Transarterial embolisation was successfully performed. Active contrast extravasation over a branch of the left hepatic artery was demonstrated but controlled by Gelfoam injection.
 
The patient was then transferred to the intensive care unit. Rotational thromboelastometry (ROTEM®; Tem International GmbH, Munich, Germany) was performed to guide transfusion strategy (Fig a). Maximum lysis was shown to be 100%, indicating abnormally accelerated clot lysis. Maximum lysis over 15% is diagnostic of hyperfibrinolysis. The lysis index at 30 minutes was 5%, indicating almost complete clot dissolution 30 minutes after initial formation. No dysfunction in coagulation activation or clot propagation was otherwise detected. Tranexamic acid 1 g was administrated according to the interpretation of ROTEM results. A follow-up ROTEM analysis after antifibrinolytic treatment demonstrated restoration of normal fibrinolysis (Fig b). Haemostasis was achieved and no further blood transfusion was needed.
 

Figure. (a) Hyperfibrinolysis detected by rotational thromboelastometry. (b) Restoration of normal fibrinolysis after antifibrinolytic treatment
 
Testing for hepatitis B surface antigen was later revealed to be reactive. This patient probably had liver cirrhosis and HCC consequent to chronic hepatitis B infection. The occurrence of ruptured HCC tipped the balance in this vulnerable patient. He developed abdominal compartment syndrome and hepatic failure. The sequential organ failure assessment score was 13 with an estimated mortality of over 90%. The surgical team advised optimum medical supportive treatment in view of the extremely high operative risk. The patient succumbed 16 hours after hospital admission.
 
Discussion
Haemocoagulation is a complex interaction of procoagulants, anticoagulants, fibrinolytic proteins, and cellular components. Platelets are activated in response to vascular injury, leading to primary haemostasis. Activated platelets adhere to damaged endothelium and aggregate to create a temporary platelet plug. Secondary haemostasis involves activation of the coagulation cascade, resulting in fibrin formation. The platelet plug is strengthened by the cross-linked fibrin to form a stable clot. Fibrinolysis serves as the final stage of coagulation to regulate the extent of clot formation and to maintain vascular patency. Cross-linked fibrin is broken down by plasmin and normal blood flow is restored.
 
Hyperfibrinolysis refers to excessive fibrinolytic activity that threatens clot integrity and leads to defective haemostasis. It is common in patients with chronic liver disease, major trauma, and obstetric complications. However, the incidence is not well studied and it has often been underdiagnosed due to an absence of appropriate tests.1 Conventional coagulation tests, such as prothrombin time, activated partial thromboplastin time, and thrombin time, are ineffective in detecting hyperfibrinolysis. Viscoelastic haemostatic assays are the only tests for rapid detection and quantification of hyperfibrinolysis.2
 
Rotational thromboelastometry is a form of viscoelastic assay. It provides a global haemostatic assessment from initial platelet activation, through platelet aggregation, clot strengthening by cross-linked fibrin, to clot dissolution. The degree of clot lysis is expressed numerically as maximum lysis. Hyperfibrinolysis is diagnosed when maximum lysis exceeds 15% within a 60-minute ROTEM analysis. Schöchl et al3 further quantified this condition based on the time course of clot dissolution, as reflected by the lysis index at 30 minutes and at 60 minutes. They categorised complete clot lysis within 30 minutes as fulminant hyperfibrinolysis; intermediate when complete clot lysis was within 30 to 60 minutes; and late when complete clot lysis exceeded 60 minutes. Prompt recognition of hyperfibrinolysis by ROTEM analysis guides appropriate antifibrinolytic therapy. Untreated hyperfibrinolysis has been shown to be associated with refractory bleeding and increased mortality.1
 
Rotational thromboelastometry has multiple advantages over conventional coagulation tests. In contrast to conventional coagulation tests that use plasma, ROTEM uses whole blood and can determine the contribution of both cellular and plasma components of haemostasis. Conventional coagulation tests provide only a quantitative assessment of individual procoagulation factors; results are not necessarily a good indication of the in vivo haemostatic process, especially in patients with chronic liver disease.4 Rotational thromboelastometry also provides real-time functional assessment of the haemostatic process, from clot formation to its lysis, and is useful for identifying hyperfibrinolysis. There is evidence that use of ROTEM-guided haemostatic strategy reduces transfusion requirement in different clinical settings.5 6 7
 
Understanding its limitations is equally important in the interpretation of ROTEM analysis. It is insensitive to the effect of platelet inhibitors such as aspirin and clopidogrel. Thrombin, the strongest activator of platelets, is produced in large amounts during ROTEM analysis, masking the inhibitory effects of antiplatelet agents.8 It is also poor at detecting conditions that affect platelet adhesion and aggregation, with Von Willebrand’s disease being a well-known example.9 The ROTEM analysis is undertaken at 37°C to mimic physiological conditions so the negative effect of hypothermia on coagulation is not reflected by the analysis.9
 
In conclusion, owing to the limitations of conventional coagulation tests, hyperfibrinolysis is frequently underdiagnosed. With its ability of real-time functional haemostatic assessment from clot formation to lysis, ROTEM analysis allows better insight into the complex haemocoagulation process. The rapid detection of hyperfibrinolysis by ROTEM can guide prompt antifibrinolytic treatment, possibly reducing the transfusion requirement in bleeding patients.
 
Author contributions
Concept or design: KM Kwok, KL Lee, SY Lam, T Liong, KI Law.
Acquisition of data: KM Kwok.
Analysis or interpretation of data: KM Kwok, KL Lee, SY Lam, T Liong, KI Law.
Drafting of the manuscript: KM Kwok.
Critical revision of the manuscript for important intellectual content: All authors.
 
Conflicts of interest
The authors have no conflicts of interest to disclose.
 
Funding/support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patient was treated in accordance with the Declaration of Helsinki. Patient was incapable to provide informed consent for publication.
 
References
1. Theusinger OM, Wanner GA, Emmert MY, et al. Hyperfibrinolysis diagnosed by rotational thromboelastometry (ROTEM) is associated with higher mortality in patients with severe trauma. Anesth Analg 2011;113:1003-12. Crossref
2. Yeung MC, Tong SY, Tong PY, Cheung BH, Ng JY, Leung GK. Use of viscoelastic haemostatic assay in emergency and elective surgery. Hong Kong Med J 2015;21:45-51. Crossref
3. Schöchl H, Frietsch T, Pavelka M, Jámbor C. Hyperfibrinolysis after major trauma: differential diagnosis of lysis patterns and prognostic value of thrombelastometry. J Trauma 2009;67:125-31. Crossref
4. Tripodi A, Mannucci PM. The coagulopathy of chronic liver disease. N Engl J Med 2011;365:147-56. Crossref
5. De Pietri L, Bianchini M, Montalti R, et al. Thrombelastography-guided blood product use before invasive procedures in cirrhosis with severe coagulopathy: a randomized, controlled trial. Hepatology 2016;63:566-73. Crossref
6. Veigas PV, Callum J, Rizoli S, Nascimento B, da Luz LT. A systematic review on the rotational thrombelastometry (ROTEM®) values for the diagnosis of coagulopathy, prediction and guidance of blood transfusion and prediction of mortality in trauma patients. Scand J Trauma Resusc Emerg Med 2016;24:114. Crossref
7. Vymazal T, Astraverkhava M, Durila M. Rotational thromboelastometry helps to reduce blood product consumption in critically ill patients during small surgical procedures at the intensive care unit—a retrospective clinical analysis and literature search. Transfus Med Hemother 2018;45:385-7. Crossref
8. Lang T, von Depka M. Possibilities and limitations of thrombelastometry/-graphy [in German]. Hamostaseologie 2006;26(3 Suppl 1):S20-9. Crossref
9. Srivastava A, Kelleher A. Point-of-care coagulation testing. Continuing Educ Anaesthesia Crit Care Pain 2013;13:12-6. Crossref

Clinical experience in diagnosis and management of acquired methaemoglobinaemia: a case report and retrospective review

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Clinical experience in diagnosis and management of acquired methaemoglobinaemia: a case report and retrospective review
TT Chan, MB, BS, MPH1; William CY Leung, MB, BS2; CK Chan, MB, BS FHAKM (Emergency Medicine)3; Heinz KT Lo, MB, BS4; Winnie WY Tso, MB, BS, FHKAM (Paediatrics)5; SH Tsui, MB, BS, FHKAM (Emergency Medicine)1; Thomas SY Chan, FHKCP, FHKAM (Medicine)2; Richard SK Chang, MB, BS, MRCP (HK)2
1 Accident and Emergency Department, Queen Mary Hospital, Hong Kong
2 Department of Medicine, Queen Mary Hospital, Hong Kong
3 Clinical Toxicology Department, United Christian Hospital, Hong Kong
4 Department of Paediatrics, Kwong Wah Hospital, Hong Kong
5 Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong
 
Corresponding author: Dr Richard SK Chang (changsk@ha.org.hk)
 
 Full paper in PDF
 
Case reports
Case 1
In June 2008, a 9-month-old boy with unremarkable medical and developmental history presented to the emergency department with acute cyanosis. The child had been fed about 200 g of congee containing rice, vegetables, fish, and egg. He was then noted to have pallor of face and perioral cyanosis. He was conscious and irritable and reported to have vomiting. His respiratory rate was 40 breaths per minute and heart rate was 190 beats per minute. Pulse oximetry showed 90% oxygen saturation on 100% oxygen via a face mask. Physical examination was otherwise unremarkable. He was admitted to the paediatric intensive care unit. During blood sampling, his blood was noted to be chocolate brown. While on 100% oxygen, his arterial blood gas showed a pH value of 7.33, PaO2 51.8 kPa, PaCO2 4.2 kPa, and bicarbonate 17 mmol/L. Blood methaemoglobin (MetHb) level was 51%. He was treated with intravenous methylene blue 15 mg (about 1.5 mg/kg) and urine was observed to be light blue (Fig). His cyanosis resolved within 1 hour after treatment and blood oxygen saturation returned to normal without oxygen supplementation. The MetHb level dropped to 1% within 30 minutes after treatment. Mutation screen of cytochrome B5 reductase gene (CYB5R3) was negative for the patient and both parents.
 

Figure. Case 1: a 9-month-old boy with methaemoglobinaemia. (a) Chocolate brown blood taken after admission and (b) light blue urine after intravenous methylene blue treatment
 
A high urinary nitrate level of 315 mg/L (reference range, 41.0-55.6 mg/L) was detected. Toxicology showed high nitrate and nitrite content in the congee consumed by the infant, 150 mg/L and 47.7 mg/L, respectively. The uncooked vegetable Amaranthus remnant contained nitrate but at a safe level. Water used for cooking had come from a regular tap, not from a well that could otherwise have been a source of contamination.
 
The advised daily intake of nitrates and nitrites is 0 to 3.7 mg/kg and 0 to 0.07 mg/kg body weight, respectively. Our patient weighted 9.2 kg and his single-day consumption of nitrates and nitrites was 34 mg and 0.644 mg, respectively. When he consumed 200 g of congee, he consumed 31.8 mg of nitrates and 9.74 mg of nitrites in one meal. The prescribed advised daily intake is for adults; a lower limit should apply for children. The patient has been followed up for 5 years with no recurrence of methaemoglobinaemia.
 
Case 2
In November 2018, a 50-year-old man with a history of schizophrenia was admitted following massive zopiclone overdose. He had taken more than 100 tabs of the hypnotic of 7.5 mg each. There was no evidence of carbon monoxide inhalation. His presenting symptoms were dizziness, nausea, and reduced urine output. He was noted to be cyanotic and with oxygen saturation of 85% on 100% oxygen. During blood sampling, his blood was noted to be chocolate brown. Serum MetHb level was 40.3% initially. Methylene blue 70 mg (around 1 mg/kg) as a slow intravenous bolus was administered in the emergency department and 1 hour later serum MetHb level had fallen to 19.3%. Carboxyhaemoglobin was 3.8%. He was admitted to the adult intensive care unit and received a further dose of intravenous methylene blue 70 mg. His saturation improved to 96% on pulse oximetry on oxygen supplementation at 1 litre per minute. Repeat measurement of MetHb showed it to be <0.1%. Carboxyhaemoglobin level peaked at 10% and gradually decreased. Urine was deep green in colour after methylene blue treatment. He also developed acute kidney injury (creatinine level peaked at 1239 μmol/L) that required haemodialysis and a normochromic normocytic anaemia (trough haemoglobin level 6.2 g/dL). Haptoglobin level was low, indicative of haemolytic anaemia. Although evidence of oxidative haemolysis, such as Heinz bodies, was not documented on blood film examination, zopiclone-induced oxidative stress was probably the cause of haemolysis. Renal ultrasonography showed only mild renal parenchymal disease. His condition stabilised after an 11-day stay in the intensive care unit.
 
Retrospective analysis
To supplement the above cases, we searched through the computerised medical record system of our institution and identified all in-patients with International Classification of Diseases-9 code of 289.7, ‘Methemoglobinemia’, from January 2000 to December 2018. We identified 21 patients with acquired methaemoglobinaemia, aged 14 days to 67 years (Table). The most common cause was deliberate self-harm by overdosing with zopiclone. The most common clinical presentation was unexplained desaturation on pulse oximetry despite oxygen supplementation. Nine patients received methylene blue. One patient with coexisting glucose-6-phosphate dehydrogenase (G6PD) deficiency was given ascorbic acid. Response to methylene blue was prompt in all cases, with MetHb falling to a non-toxic level soon after treatment.
 

Table. Clinical features of patients with acquired methaemoglobinaemia
 
Discussion
Infants or young children may be more susceptible to methaemoglobinaemia as the haemoglobin enzymes, such as cytochrome-b5 MetHB reductase, are immature. As in Case 1, nitrates in vegetables can cause methaemoglobinaemia, and this underlying cause is preventable. Nitrates are commonly found in agricultural products and well water, and can be formed by bacteria from nitrates. Home-prepared vegetables should be avoided in infants younger than 3 months of age.1 Farmers should avoid excessive use of nitrate-containing products during vegetable production, as suggested by agricultural guidelines.2 Well water should be monitored for nitrate contamination. Nitrate content can be converted to nitrite due to improper storage in a flask. Nitrate can also be reduced to nitrite by nitrate reductase intrinsic to plants or bacteria. Thus, proper washing, cooking and storage of food rich in nitrates is essential.
 
Medication is a main cause of acquired methaemoglobinaemia. Zopiclone overdose accounted for a significant portion in our series. As a non-benzodiazepine hypnotic, zopiclone is widely prescribed. Massive zopiclone overdose is relatively more common in Hong Kong because it can be obtained without a prescription. Intentional overdose has been reported in those attempting suicide.3 Zopiclone is known to be associated with methaemoglobinaemia especially following massive overdose, and with haemolytic anaemia and kidney injury. The elevated carboxyhaemoglobin in Case 2 was possibly endogenous due to haemolysis, as metabolism of haem via haem oxidase produces one molecule of CO per molecule of haem degraded.4
 
Other substances that can lead to methaemoglobinaemia include dapsone, nitrogen, and alanine. They induce oxidative stress in erythrocytes. In susceptible subjects who lack antioxidative enzymatic activity, the ferrous ion in the haem group is oxidised to a ferric state, forming MetHb that is incapable of binding oxygen. The oxygen dissociation curve is shifted to the left; oxygen desaturation, around 85%, is common in methaemoglobinaemia. The underlying mechanism is related to the absorption of light wavelengths employed by emitter and detector of the pulse oximeter.
 
Clinical presentations of methaemoglobinaemia include both central and peripheral cyanosis, dizziness, headache, dyspnoea, and malaise. In extreme cases, coma or death may occur if MetHb exceeds 30% to 40%. G6PD deficiency can exacerbate the methaemoglobinaemia and concomitant haemolysis. Vigilance is needed for clinical diagnosis. Unexplained cyanosis or poor oxygen saturation should prompt clinicians to consider methaemoglobinaemia. Medication and dietary histories, chemical contacts, recent medical or dental procedures and occupational exposure are conducive to diagnosis. Treatment mainly depends on the level of MetHb. For low levels, no specific treatment is needed. Methylene blue is usually indicated if MetHb exceeds 20%. It acts as a cofactor to increase erythrocyte reduction of MetHb to haemoglobin in the presence of NADPH. Therapeutic response is usually prompt. In our series, MetHb level dropped in all cases to below 20% after a single dose of methylene blue. Methylene blue should be used with caution in patients with G6PD deficiency as haemolysis can result from repeated use. An excessive cumulative dose of methylene blue can also potentially induce haemolysis. Ascorbic acid, an antioxidant, may be used as an alternative, either orally or intravenously.5 It works by scavenging free radicals and protects cells against oxidative stress, acting as a co-factor for NADP reductase and directly reducing MetHb.
 
In conclusion, methaemoglobinaemia can affect a wide age range of patients and be due to a variety of agents. Effective treatment exists and the response is usually satisfactory.
 
Author contributions
Concept or design: All authors.
Acquisition of data: TT Chan, RSK Chang.
Analysis or interpretation of data: All authors.
Drafting of the manuscript: TT Chan, RSK Chang.
Critical revision for important intellectual content: All authors.
 
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
The authors have no conflicts of interest to disclose.
 
Funding/support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patients were treated in accordance with the Declaration of Helsinki, and provided informed consent for all treatments and procedures. The retrospective analysis of patient data was approved by the University of Hong Kong/Hospital Authority Hong Kong West Cluster institutional review board (Ref UW 19-205) and the requirement for patient consent for publication was waived.
 
References
1. Greer FR, Shannon M, American Academy of Pediatrics Committee on Nutrition, American Academy of Pediatrics Committee on Environmental Health. Infant methemoglobinemia: the role of dietary nitrate in food and water. Pediatrics 2005;116:784-6. Crossref
2. European Commission. Encouraging low-input farming in the EU. Available from: https://ec.europa.eu/info/food-farming-fisheries/sustainability/environmental-sustainability/low-input-farming. Accessed 8 Aug 2019.
3. Chan TY. Zopiclone induced methemoglobinemia and hemolytic anemia. Int J Clin Pharmacol Ther 2014;52:402-6. Crossref
4. Hampson NB. Carboxyhemoglobin elevation due to hemolytic anemia. J Emerg Med 2007;33:17-9. Crossref
5. Lee KW, Park SY. High-dose vitamin C as treatment of methemoglobinemia. Am J Emerg Med 2014;32:936. Crossref

Gas embolism and hyperbaric oxygen therapy: a case series

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Gas embolism and hyperbaric oxygen therapy: a case series
Jeffrey CW Chau, MB, BS, MRCS(Ed)1; Joe KS Leung, MB, ChB, FRCS1; WW Yan, FRCP, FHKCP2
1 Department of Accident and Emergency, Pamela Youde Nethersole Eastern Hospital, Hong Kong
2 Intensive Care Unit, Pamela Youde Nethersole Eastern Hospital, Hong Kong
 
Corresponding author: Dr Jeffrey CW Chau (drjhealthcare@gmail.com)
 
 Full paper in PDF
 
Case report
Patient 1
A 79-year-old man presented with left-sided weakness, drowsiness and dysphasia following left atrial appendage occlusion implantation in a cardiac intensive care unit. A sudden drop in systolic blood pressure to 40 mmHg was noted. Echocardiogram and angiogram revealed no obvious coronary artery disease. Computed tomography (CT) of the brain showed no major vessel occlusion or gas pocket. A new CT of the brain showed more established infarct and oedema. Four sessions of hyperbaric oxygen therapy (HBOT) were conducted in accordance with United States Navy Treatment Tables (USNTT)1: two USNTT6 and two USNTT5.
 
Patient 2
A 40-year-old woman was admitted to a surgical unit for suspected acute appendicitis. Urgent CT of the abdomen with contrast was performed, but approximately 60 mL of air was injected intravenously during the procedure and gas was evident in the right ventricle. Luckily, she was asymptomatic as the gas emboli had entered only the venous system and remained in the heart. One session of HBOT was conducted with USNTT6.
 
Patient 3
A 57-year-old woman underwent fine needle aspiration cytology under CT guidance for lung mass. The patient developed sudden onset bilateral anopia and left upper limb weakness during the procedure. Computed tomography brain and thorax identified a small gas embolism in the pulmonary vein with pulmonary haemorrhage. No obvious gas bubble was noted in the brain. A total of four sessions of HBOT were conducted with two USNTT6 and two USNTT5.
 
Patient 4
An 84-year-old man underwent CT-guided lung biopsy for right lung mass but experienced an acute deterioration in Glasgow Coma Scale (GCS) score. Urgent CT of the brain showed multiple acute gas emboli and confirmed the diagnosis of cerebral arterial gas embolism (AGE). On arrival at the HBOT centre, he had GCS of 13/15 and right limb weakness with power of 1/5 and 3/5, respectively. Two sessions of HBOT were conducted with USNTT6.
 
Patient 5
A 66-year-old man with biliary pancreatitis underwent urgent endoscopic retrograde cholangiopancreatography. After the procedure he developed left-sided weakness with limb power of 0/5 after 5 minutes. Urgent CT of the brain revealed branching gas densities at the sulcal space of his right frontal and parietal lobes (Fig 1). Two sessions of HBOT with USNTT6 were conducted and the patient’s symptoms considerably improved.
 

Figure 1. (a, b) A 66-year-old man with biliary pancreatitis developed left-sided weakness 5 minutes after urgent endoscopic retrograde cholangiopancreatography. Computed tomography of the brain revealed branching gas density in the right frontal and parietal lobes (arrows)
 
Patient 6
A 72-year-old man underwent CT-guided fine needle aspiration cytology for a lung lesion. The patient developed transient hypotension on needle removal and CT of the thorax revealed gas embolism in his left ventricle with no pneumothorax (Fig 2). The patient remained asymptomatic with no neurological deficit. Gas embolism had been introduced through the pulmonary circulation but remained in the heart, avoiding the complication of cerebral arterial occlusion. One session of HBOT was conducted with USNTT6.
 

Figure 2. (a, b) A 72-year-old man developed transient hypotension on needle removal after computed tomography–guided fine needle aspiration cytology for a lung lesion. Computed tomography of the thorax revealed gas density (arrows) evident in the left ventricle with no pneumothorax
 
Discussion
Gas embolism is a serious and life-threatening condition. It is usually iatrogenic and should be treated promptly to prevent serious complications such as cerebral AGE. It presents with sudden deterioration in neurological and haemodynamic status following risky medical procedures, most notably lung biopsy and cardiac interventions. This case report revealed six patients with gas embolism: five with AGE and one with venous gas embolism. Four patients with AGE manifested as cerebral AGE with neurological deficits such as limb weakness and anopia (Table).
 

Table. Patients treated with HBOT for cerebral arterial gas embolism
 
Rationale for using hyperbaric oxygen therapy
As soon as AGE is suspected, the patient should start receiving 100% high-flow oxygen and be placed in the right lateral decubitus position. The definitive treatment for AGE is HBOT with 100% oxygen, although no randomised controlled trials have been conducted to confirm its efficacy in this disease. Hyperbaric oxygen therapy “crushes” the bubbles with pressure, accelerates gas diffusion and bubble resolution with oxygen, oxygenates ischaemic tissue, reduces cerebral oedema, and decreases neutrophil adhesion to the endothelium.1 2 A retrospective study in France showed that the initial neurological symptoms were impaired consciousness (70%), focal motor deficits (60%), seizures (11%), visual disturbance (10%), dysarthria/aphasia (5%) and vertigo (5%). In all, 26% of patients were haemodynamically unstable and subject to hypotension, circulatory collapse, and cardiac arrest. Respiratory disturbances such as dyspnoea, cough or chest pain were present in 23% of patients.3
 
In a study of 45 patients with AGE, good neurological outcome was achieved in 27 (60%) of them.4 Time to receipt of HBOT was the only statistically significant factor predictive of a good outcome with mean delay 8.8 hours.4 Although probability of a good outcome is highest when HBOT is administered as soon as possible, a good response can still be obtained if treatment is delayed for longer than 24 hours.3 5 There is a tendency for patients with AGE to deteriorate after their initial apparent recovery; thus, early HBOT is still recommended for patients with a seemingly spontaneous recovery.6 Although identification of gas bubbles on CT of the brain is not a prerequisite to HBOT, early treatment can also attenuate leucocyte adherence to damaged endothelium and secondary inflammation that in turn facilitate the return of blood flow. However, gas bubbles can persist for several days, and many case reports have demonstrated the benefit of HBOT after delays ranging from hours to days. Complete recovery has been reported in one patient in whom treatment was delayed for 28 hours. In 2017, another patient who was deeply comatose with AGE recovered and was able to lead a functional life after HBOT had been delayed for 6 days.7 8 In our cases, all the patients were treated within 7 hours onset of symptoms. Most fully recovered except for Patient 1. The aetiology of neurological deterioration in Patient 1 was likely due to a combination of gas embolism, clots, and hypotension.
 
Hyperbaric oxygen therapy treatment tables
According to the United States Navy Diving Manual,9 USNTT6 is the standard initial compression therapy for AGE. It is a table with maximum pressure up to 2.8 atmospheres absolute (ATA) for 1 hour 15 minutes with slow depressurisation to 1.9 ATA lasting for 2.5 hours. Total treatment time is approximately 4 hours 45 minutes. There is no conclusive evidence that use of pressure higher than 2.8 ATA has any advantage. Use of pressure up to 6 ATA poses further risks to the patient and attending staff, including gas toxicity and decompression sickness. Typically, one to three hyperbaric treatments are required to treat AGE; the clinical condition should be monitored until there is no further stepwise improvement. There are reports that up to 10 treatments have been required to reach a stable condition.10 11
 
The USNTT5, which is a shorter treatment used to treat mild decompression sickness, may be used together with USNTT6 for AGE when prolonged treatment is required. This treatment table advises a maximum pressure up to 2.8 ATA for 45 minutes with slow depressurisation to 1.9 ATA for 30 minutes. Total treatment time is approximately 2 hours 15 minutes. According to the Royal Navy Diving manual,12 which is commonly used in Europe, RN62 Table is the standard to treat AGE. This treatment is similar to USNTT6 with a maximum pressure of 2.8 ATA.
 
Conclusion
Arterial gas embolism presents in highly variable ways with no pathognomonic signs or symptoms. It is uncommon to achieve complete consensus on the diagnosis, and it is common practice to err on the side of caution. Hyperbaric oxygen therapy should be initiated as early as possible although delayed treatment is also effective. Failure to administer treatment can result in long-term disability. Hyperbaric oxygen therapy should be considered for any suspected AGE.
 
Author contributions
Concept or design: JCW Chau.
Acquisition of data: JCW Chau.
Analysis or interpretation of data: JCW Chau.
Drafting of the manuscript: All authors.
Critical revision of the manuscript for important intellectual content: All authors.
 
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patients were treated in accordance with the Declaration of Helsinki. The patients provided informed consent for the treatment/procedures, and verbal consent for publication.
 
References
1. United States Navy. Diagnosis and treatment of decompression sickness and arterial gas embolism. In: US Navy Diving Manual. Revision 7. Vol 5. Available from: https://www.navsea.navy.mil/Portals/103/Documents/SUPSALV/Diving/US%20DIVING%20MANUAL_REV7.pdf?ver=2017-01-11-102354-393. Accessed 30 Sep 2020.
2. Grim PS, Gottlieb LJ, Boddie A, Batson E. Hyperbaric oxygen therapy. JAMA 1990;263:2216-20. Crossref
3. Blanc P, Boussuges A, Henriette K, Sainty JM, Deleflie M. Iatrogenic cerebral air embolism: importance of an early hyperbaric oxygenation. Intensive Care Med 2002;28:559-63.Crossref
4. Beevor H, Frawley G. Iatrogenic cerebral gas embolism: analysis of the presentation, management and outcomes of patients referred to The Alfred Hospital Hyperbaric Unit. Diving Hyperb Med 2016;46:15-21.
5. Massey EW, Moon RE, Shelton D, Camporesi EM. Hyperbaric oxygen therapy of iatrogenic air embolism. J Hyperb Med 1990;5:15-21.
6. Pearson RR, Goad RF. Delayed cerebral edema complicating cerebral arterial gas embolism: case histories. Undersea Biomed Res 1982;9:283-96.
7. Benson J, Adkinson C, Colier R. Hyperbaric oxygen therapy of iatrogenic cerebral arterial gas embolism. Undersea Hyperb Med 2003;30:117-26.
8. Perez MF, Ongkeko Perez JV, Serrano AR, Andal MP, Aldover MC. Delayed hyperbaric intervention in lifethreatening decompression illness. Diving Hyperb Med 2017;47:257-9 Crossref
9. United States Navy. US Navy Diving Manual. Revision 7. Vol 5: Diving medicine and recompression chamber operations. 2016. Available from: https://www.navsea.navy.mil/Portals/103/Documents/SUPSALV/Diving/US%20DIVING%20MANUAL_REV7.pdf?ver=2017-01-11-102354-393. Accessed 30 Sep 2020.
10. Vann RD, Butler FK, Mitchell SJ, Moon RE. Decompression illness. Lancet 2011;377:153-64.Crossref
11. Undersea & Hyperbaric Medical Society. UHMA Best Practice Guidelines: Prevention and Treatment of Decompression sickness and arterial gas embolism. Available from: https://www.uhms.org/images/DCS-AGE-Committee/dcsandage_prevandmgt_uhms-fi.pdf. Accessed 30 Sep 2020.
12. Royal Navy, Ministry of Defence. Diving Manual. HM Stationery Office, London; 1972.

Isolated hereditary diffuse palmoplantar keratoderma in Hong Kong Chinese patients: a case series

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Isolated hereditary diffuse palmoplantar keratoderma in Hong Kong Chinese patients: a case series
PT Yu, MB, BS, FHKAM (Paediatrics)1; Stephanie Ho, MB, ChB, FHKAM (Paediatrics)1; SC Ng, MB, BS, FHKAM (Medicine)2; FM Lo, MB, BS, FHKAM (Paediatrics)1; HM Luk, MB, BS, FHKAM (Paediatrics)1
1 Clinical Genetic Service, Department of Health, Hong Kong
2 Social Hygiene Clinic, Department of Health, Hong Kong
 
Corresponding author: Dr HM Luk (luksite@gmail.com)
 
 Full paper in PDF
 
Case report
Patient 1
A 26-year-old man presented with a history of hyperhidrosis of the palms and soles since age 6 months. He subsequently developed progressive palmoplantar hyperkeratosis. He enjoyed otherwise good past health. His parents were non-consanguineous and there was no significant family history. Physical examination revealed bilateral symmetrical thick waxy hyperkeratosis of the palms and soles with well-demarcated transgradient margins and focal macerated erosions over the palms. Knuckle pads were observed on the dorsum of the proximal interphalangeal joints of the fingers and toes (Fig 1). There were no associated ectodermal manifestations, brachydactyly, nail abnormality or deformity. There was no insolate lesion over the elbows or knees. Medical exome sequencing identified homozygous pathogenic variants in NM_020427.2(SLURP1) c.147_150delCTGC, p.Cys50*. The molecular diagnosis of Meleda disease [MIM #248300] was confirmed.
 

Figure 1. Clinical photographs of the dermatological features of three patients with palmoplantar keratoderma (PPK). (a-d) Patient 1, 26-year-old man. Bilateral thick waxy hyperkeratosis of the palms and soles with well-demarcated transgradient margins and focal macerated erosions over the palms. (b, d) Knuckle pads are evident on the dorsum of the proximal interphalangeal joints of the fingers and toes. (e-h) Patient 2 65-year-old woman. Diffuse yellowish to erythematous PPK with transgradiens over bilateral palms and soles. Tapering of the fingertips with mutilating features such as flexion contracture of the fingers and cutaneous syndactyly are evident. There is also total nail dystrophy of all nails. (i-l) Patient 3, 18-year-old woman. Clinical appearance of Nagashima-type PPK: mild bilateral diffuse erythematous palmoplantar hyperkeratosis extending to the dorsal surfaces of the hands and feet with well-demarcated borders
 
Patient 2
A 65-year-old woman presented with a history of diffuse hyperkeratosis of bilateral palms and soles since early infancy. She otherwise enjoyed good past health. Her parents were first-degree cousins and her younger brother had similar dermatological features. Skin biopsy revealed non-epidermolytic keratoderma. Physical examination showed diffuse yellowish to erythematous palmoplantar keratoderma (PPK) with transgradiens over bilateral palms and soles and well-demarcated margins. The fingers were mutilating with camptodactyly and cutaneous syndactyly. There was total nail dystrophy of all fingernails and toenails but no insolate lesions over the elbows or knees (Fig 1). Whole exome sequencing revealed homozygous likely pathogenic variants in SLURP1 NM_020427.2(SLURP1) c.256G>A, p.Gly86Arg. The molecular diagnosis of Meleda disease [MIM #248300] was confirmed.
 
Patient 3
An 18-year-old woman presented with mild bilateral diffuse erythematous palmoplantar keratosis extending to the dorsal surfaces of the hands and feet since early infancy (Fig 1). There was no associated systemic involvement and no significant family history. Skin biopsy (Fig 2) revealed marked compact orthokeratosis, focal parakeratosis, mild hypergranulosis, acanthosis and psoriasiform epidermal hyperplasia, as well as mononuclear inflammatory infiltrate in the dermis.
 

Figure 2. Histology of skin biopsy from Patient 3 showing (a) marked compact orthokeratosis (closed arrows), acanthosis and psoriasiform epidermal hyperplasia (open arrows), and focal parakeratosis (arrowheads) [haematoxylin and eosin, ×25], and (b) mild hypergranulosis (closed arrow) and mononuclear inflammatory infiltrate (arrowheads) in the dermis (haematoxylin and eosin, ×100)
 
Medical exome sequencing identified biallelic pathogenic variants in NM_001040147.2(SERPINB7):c.169-1G>A, p.? and c.522dup, p.Val175Cysfs*46. The molecular diagnosis of PPK, Nagashima type [MIM #615598] was confirmed.
 
Discussion
Hereditary PPK is a heterogeneous group of disorders characterised by marked hyperkeratosis of the palms and soles due to a defect in cornification. It can occur in isolation or in association with other ectodermal defects or extracutaneous manifestations. Molecular studies are sometimes crucial to reach an accurate subtype classification as there are significant overlapping clinical features and heterogeneity among different types of hereditary PPK. Depending on the morphology of the lesions, PPK is classified into three major patterns: diffuse, focal (areata or striata), and punctate. Although precise figures of incidence are lacking, PPK is generally perceived to be rare. In Asia, the most frequent type of PPK is Nagashima PPK, with an estimated prevalence of 3.1 per 10 000 population.1 This article summarises the clinical features and molecular findings in three Chinese individuals with isolated diffuse hereditary PPK recruited from a single centre and highlights the significance of genetic testing in reaching an accurate classification and diagnosis.
 
Meleda disease (also known as Mal de Meleda) has an autosomal recessive pattern of inheritance and is characterised by an early onset of bilateral, diffuse, well-demarcated thick and waxy PPK in a glove and stocking pattern. It is rare, with a prevalence of 1:100 000.2 Palmoplantar erythema can be evident from early infancy and tends to progress to thick hyperkeratosis as an affected individual ages. Meleda disease is commonly associated with hyperhidrosis and nail anomalies such as koilonychia, onychogryphosis, and subungual hyperkeratosis. Anomalies of the digits, including pseudoainhum, contracture, tapering of digits, knuckle pads and fifth-finger dysplasia have been reported. Oral manifestations including lower-lip angular cheilitis, high arch palate and perioral erythema can be variably present. Skin biopsy is characterised by histological findings of hyperkeratosis and acanthosis in the epidermis without evidence of epidermolysis.2 SLURP-1 was subsequently identified to be responsible for Meleda disease in 2001 by Fischer et al.3 SLURP-1 is involved in regulation of inflammation and keratinocyte apoptosis. Treatment options include oral retinoids, topical keratolytics, and surgical excision of hyperkeratosis followed by placement of a full-thickness skin graft. Infection is treated with antibacterials and antifungals, with some centres advocating the use of prophylactic topical antifungals due to a susceptibility to tinea infection.
 
Nagashima-type PPK (NPPK) is probably the most common form of PPK among patients of Asian ethnicity. It was initially described by Nagashima4 in 1977. Biallelic mutations of SERPINB7 were found to be causative of NPPK in 2013.5 The hyperkeratosis is non-progressive after puberty and has milder clinical features when compared with Meleda disease. It is characterised by diffuse mild erythematous non-mutilating palmoplantar hyperkeratosis that can transform into a spongy white appearance after immersion in water. The dorsal surface of the hands and feet, ankles, Achilles tendon area, elbows and knees can be involved. Palmoplantar hyperkeratosis occurs in isolation without associated ectodermal or extracutaneous manifestations. Histological findings are unremarkable with orthohyperkeratosis, acanthosis and mild perivascular inflammatory infiltration of lymphocytes in the upper dermis.1 A nonsense c.796C>T founder mutation in SERPINB7 has been reported to be prevalent in Chinese patients with NPPK,1 but c.169-1G>A in Patient 3 is novel to the literature. No curative treatment is available but topical application of gentamicin has been investigated and appears promising.6
 
Conclusion
We have reported three cases of PPK that illustrate the clinical phenotype and molecular findings of this particular subgroup of genodermatoses. Molecular investigations may be warranted for accurate diagnosis of PPK and to determine its inheritance, and may be beneficial in reproductive management within the family.
 
Author contributions
All authors contributed equally to the concept or design of the study, acquisition of the data, analysis or interpretation of the data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
The authors have no conflicts of interest to disclose.
 
Acknowledgement
The authors thank Dr WC Siu for preparing the histology photographs.
 
Funding/support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patients were treated in accordance with the Declaration of Helsinki. The patients provided written informed consent for all treatments and procedures, and for publication of this report.
 
References
1. Yin J, Xu G, Wang H, et al. New and recurrent SERPINB7 mutations in seven Chinese patients with Nagashima-type palmoplantar keratosis. J Invest Dermatol 2014;134:2269-72. Crossref
2. Perez C, Khachemoune A. Mal de Meleda: a focused review. Am J Clin Dermatol 2016;17:63-70. Crossref
3. Fischer J, Bouadjar B, Heilig R, et al. Mutations in the gene encoding SLURP-1 in Mal de Meleda. Hum Mol Genet 2001;10;875-80. Crossref
4. Nagashima M. Palmoplantar keratosis. In: Miura O, Ochiai K, editors. Handbook of Human Genetics [in Japanese]. Vol 9. Tokyo: Igaku Shoin; 1977: 23-7.
5. Kubo A, Shiohama A, Sasaki T, et al. Mutations in SERPINB7, encoding a member of the serine protease inhibitor superfamily, cause Nagashima-type palmoplantar keratosis. Am J Hum Genet 2013;93:945-56. Crossref
6. Ohguchi Y, Nomura T, Suzuki S, et al. Gentamicin-induced readthrough and nonsense-mediated mRNA decay of SERPINB7 nonsense mutant transcripts. J Invest Dermatol 2018;138:836-43. Crossref

Acute flaccid paralysis associated with enterovirus D68 infection: a case report

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Acute flaccid paralysis associated with enterovirus D68 infection: a case report
Wilson YK Chan, FHKAM (Paediatrics)1,2; Stella HY Chim, FHKAM (Paediatrics)2; Donald ML Tse, FHKAM (Radiology)3; PL Ho, FHKAM (Pathology)4
1 Department of Paediatrics and Adolescent Medicine, Hong Kong Children’s Hospital, Hong Kong
2 Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, Hong Kong
3 Department of Diagnostic Radiology, Queen Mary Hospital, and St Teresa’s Hospital, Hong Kong
4 Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
 
Corresponding author: Dr Wilson YK Chan (wykchan@hku.hk)
 
 Full paper in PDF
 
Case report
In July 2017, a 28-month-old boy presented to a private outpatient clinic with a 2-day history of fever and coryzal symptoms (Table). He had enjoyed good past health and his family history was unremarkable. On clinical examination, he was noted to have respiratory distress and tachycardia. Plain radiograph of the chest (CXR) showed perihilar haziness but no consolidation. He was transferred to Queen Mary Hospital, Hong Kong, to exclude myocarditis in view of elevated serum troponin in blood taken in the private clinic. On admission, he was noted to have diffuse crepitations and wheeze suggestive of pneumonitis. Nebulised salbutamol, hypertonic saline, and intravenous cefotaxime were administered. Complete blood count revealed neutrophilia, normal liver and renal function, and normal creatine kinase level. Venous blood gas showed no acidosis. Troponin was high initially but then gradually normalised. Echocardiogram showed no features of myocarditis. Nasopharyngeal aspirate and throat swab test results were positive for enterovirus (EV)/rhinovirus ribonucleic acid (RNA) using reverse transcriptase-polymerase chain reaction (RT-PCR) detection method. EV71 RNA was not evident. Nasopharyngeal aspirate for mycoplasma, throat swab and blood culture were all negative. He then developed progressive respiratory distress with increased cough and high fever up to 40°C on day 7 of illness and CXR showed worsening of bilateral perihilar haziness. In view of the progressive respiratory failure, the child was admitted to the paediatric intensive care unit 2 days later (day 9).
 

Table. Timeline of clinical course, investigation results, treatment, and management of the index case
 
On admission to paediatric intensive care unit, he was noted to have generalised muscle weakness with a weak voice and an inability to sit up. Gag reflex and jerks were preserved. He was then intubated and ventilated under sedation. On reassessment, chest auscultation revealed decreased air entry over the left side, corresponding to the left lower zone collapse evident on CXR. He was prescribed piperacillin-tazobactam and levofloxacin. On day 10, throat swab culture grew only commensals while endotracheal aspirate revealed scanty growth of alpha-haemolytic streptococci with negative fungal smear and culture, and RT-PCR identified EV/rhinovirus. Broncho-alveolar lavage was also performed but results were unremarkable: Pneumocystis jiroveci (carinii), smear and culture for bacteria, fungus and acid-fast bacilli, and RT-PCR for cytomegalovirus, herpes simplex virus, Mycoplasma, Legionella, were all negative. Urine culture was negative for Legionella antigen.
 
On day 11, the patient exhibited paradoxical breathing on weaning of sedation along with hypotonia and paralysis of four limbs. Urgent sagittal T2-weighted magnetic resonance imaging of spine (day 11) showed mild T2 hyperintensity with mild expansion within the central portion of the cervical cord from C3 to C6 (Fig). No intraspinal mass or collection could be seen. Neurology examination was performed on day 12. Creatine kinase was normal and anti-acetylcholine receptor and anti-aquaporin-4 were negative. Eye examination the following day showed no evidence of optic neuritis. Immunoglobulin G and immunoglobulin M of anti-gangliosides were all negative. Lumbar puncture revealed normal cerebrospinal fluid level of glucose and protein. Total cell count was 100 × 106/L with predominantly (80%) neutrophils. Cerebrospinal fluid culture was negative for viruses, including EV, herpes simplex virus or varicella-zoster virus. Cerebrospinal fluid levels of oligoclonal protein and immunoglobulin G were unremarkable. The working diagnosis was transverse myelitis affecting cervical cord C3 to C6. He was prescribed pulse methylprednisolone 30 mg/kg for 5 days (day 12 to 16) followed by a tapering oral dose of prednisolone together with intravenous immunoglobulin 2 g/kg over 2 days (day 16 and 17). He was also treated with therapeutic plasma exchange with 1.5-times plasma volume for five courses over 2 weeks (day 22, 24, 26, 30, 32). His condition gradually improved and he was extubated (day 47) after 38 days of invasive ventilation. The child was successfully discharged from the paediatric intensive care unit after 2 months (day 64) and achieved full neurological recovery with intensive training by physiotherapists. Subsequent review by a microbiologist using gene sequencing of initial specimens obtained on day 3 of admission to Queen Mary Hospital revealed EV-D68 RNA in nasopharyngeal aspirate, endotracheal aspirate and stool samples. Samples remained positive for 4 weeks (day 30, during acute deterioration warranting intensive care unit admission) and were negative after 6 weeks (day 55). The definitive diagnosis was EV-D68-associated acute flaccid paralysis (AFP) although EV-D68 was not present in the cerebrospinal fluid and plasma/serum samples were not tested for EV-D68 by RT-PCR.
 

Figure. Axial (a) and sagittal (b) images on T2-weighted magnetic resonance imaging of spine showing mild T2 hyperintensity with mild expansion within central portion of cervical cord from C3 to C6
 
Discussion
Acute flaccid paralysis is defined by the World Health Organization as a clinical syndrome of diverse aetiology characterised by acute-onset limb weakness or paralysis with varying degrees of autonomic and somatic nervous system dysfunction that reaches maximum severity over a period of days or weeks in a child younger than 15 years of age.1 It is a diagnosis of exclusion. In 1962, a new strain of EV, EV-D68, was identified in Berkeley, California. In 2014, EV-D68 outbreaks were reported in 20 countries including the United States, Canada, Europe, and Asia with a total of over 2000 cases. This corresponded to an increased global incidence of AFP.2 A casual association between EV-D68 and AFP is supported by Bradford Hill criteria.3 Despite public health attempts in 1988 to eliminate AFP through the Global Polio Eradication Initiative4 and roll-out of the oral polio vaccine5 to prevent vaccine-associated poliomyelitis, the emergence of EV-D68-associated AFP has become a significant cause of neurological deficits in children since 2014. Owing to its impact on the healthcare system, a comprehensive literature review and further detailed studies are warranted. This is the first case encountered in our department. It is important for clinicians in Hong Kong to be alert for the disease.
 
As a newly emerging disease manifestation, a high index of suspicion and clinical awareness is advocated to facilitate earlier recognition and diagnosis through appropriate investigations, and presumably, improved clinical outcomes. The optimum treatment strategy has yet to be defined and preventive strategies are still being developed. Local and international notification systems as well as comprehensive surveillance are suggested since disease outbreaks may occur at any time and may have a serious impact on affected children.
 
Author contributions
Acquisition of data: WYK Chan, SHY Chim, DML Tse.
Analysis or interpretation of data: WYK Chan, DML Tse, PL Ho.
Drafting of the manuscript: WYK Chan.
Critical revision of the manuscript for important intellectual content: All authors.
 
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The parents of the patient gave consent for publication.
 
References
1. Bitnun A, Yeh EA. Acute flaccid paralysis and enteroviral infections. Curr Infect Dis Rep 2018;20:34. Crossref
2. Holm-Hansen CC, Midgley SE, Fischer TK. Global emergence of enterovirus D68: a systematic review. Lancet Infect Dis 2016;16:e64-75. Crossref
3. Messacar K, Asturias EJ, Hixon AM, et al. Enterovirus D68 and acute flaccid myelitis-evaluating the evidence for causality. Lancet Infect Dis 2018;18:e239-47. Crossref
4. World Health Organization. Global Polio Eradication Initiative. 2018. Available from: http://polioeradication.org/where-we-work/polio-endemic-countries/. Accessed 24 Mar 2018.
5. World Health Organization. Global Polio Eradication Initiative. Circulating vaccine-derived poliovirus. 2018. Available from: http://polioeradication.org/polio-today/polio-now/this-week/circulating-vaccine-derived-poliovirus/. Accessed 24 Mar 2018.

Diagnostic dilemma between skull base osteomyelitis and nasopharyngeal carcinoma: a case series

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Diagnostic dilemma between skull base osteomyelitis and nasopharyngeal carcinoma: a case series
KY Wong, MB, ChB; KC Wong, FRCSEd (ORL), FHKCORL
Department of Ear, Nose and Throat, Pamela Youde Nethersole Eastern Hospital, Hong Kong
 
Corresponding author: Dr KY Wong (wky053@ha.org.hk)
 
 Full paper in PDF
 
Case report
Skull base osteomyelitis (SBO) is a rare and life-threatening complication of otorhinological infection. The anatomical location of the disease and clinical features allow it to mimic nasopharyngeal carcinoma (NPC): a malignancy that is endemic in Southeast Asia. Suspicious clinical or radiological findings warrant prompt histological investigation for confirmation. Misdiagnosis of either entity can lead to devastating consequences of late treatment and disease progression. Our centre identified four cases of SBO between 2019 and 2020, all of which mimicked NPC at presentation. The caveats encountered during the diagnostic process are highlighted here.
 
Case 1
An 81-year-old diabetic man presented to our department with left middle ear effusion. Endoscopy revealed vague bulging over the left nasopharynx with obliteration of the left fossa of Rosenmuller. Gadolinium-enhanced magnetic resonance imaging (MRI) showed enhancing signal intensities in the left nasopharynx involving multiple skull base structures (Fig). Multiple biopsies yielded only benign results. Tissue culture grew methicillin-sensitive Staphylococcus aureus. Blood test results revealed elevated inflammatory markers including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). His plasma Epstein–Barr virus (EBV) DNA level was 0 copies/mL. The final diagnosis was SBO and the patient was treated accordingly with a good response.
 

Figure. Patient 1. Gadolinium-enhanced magnetic resonance image showing enhancing signal intensities in the left nasopharynx involving multiple skull base structures, including the left fossa of Rosenmuller (long arrow), left prevertebral muscle (short arrow), and left carotid canal (open arrow)
 
Case 2
A 76-year-old man presented with left-sided headache and left jaw pain with a recent history of lower molar tooth extraction. Physical examination revealed left otitis media with effusion, and tongue and uvula deviation. Endoscopy showed a vague swelling over the left nasopharynx. The MRI images indicated locally invasive NPC, involving the clivus and ipsilateral skull base foramina. The patient underwent multiple biopsies including under general anaesthesia with computed tomography (CT) navigation. Blood ESR and CRP levels were elevated and tissue cultures grew Candida, Pichia, and Lactobacillus. All results indicated inflammation only. The patient was treated with a prolonged course of meropenem and antifungal medication with a favourable clinical response. His headache and inflammatory markers improved, and interval MRI showed reduced signal intensities at the skull base.
 
Case 3
A 71-year-old man was referred to our clinic for persistent left otalgia, headache, and facial pain. Initial endoscopy demonstrated bulging of the left nasopharynx and left cord palsy. Computed tomography and subsequent MRI revealed a neoplastic process in the left nasopharynx with invasion of the parapharyngeal space and skull base. Prominent retropharyngeal lymph nodes were suggestive of nodal spread. Multiple biopsies were carried out, once with MRI navigation via a transsphenoidal approach towards the clivus. Results were all benign. His plasma EBV DNA level was 0 copies/mL. Cultures grew methicillin-resistant S aureus and Corynebacterium. White cell count and blood ESR and CRP levels were elevated. A prolonged course of meropenem was prescribed with consequent improvement of symptoms and reducing trend of inflammatory markers. The 3-month interval MRI demonstrated reduced enhancement of skull base structures.
 
Case 4
A 59-year-old man with poorly controlled diabetes underwent left mastoidectomy for malignant otitis externa. After surgery, he complained of persistent left temporal headache and dysphagia. Pathology from the operation was suggestive of inflammation only. Endoscopy revealed bulging of the left nasopharynx and left cord palsy. Computed tomography showed left otomastoiditis whilst MRI demonstrated an aggressive process with extensive involvement of skull base structures. Nasopharynx biopsies failed to confirm malignancy. Cultures were positive for methicillin-resistant S aureus, Staphylococcus spp, and Klebsiella. His plasma EBV DNA was 0 copies/mL. White cell count and blood ESR and CRP levels were elevated. After 6 weeks of treatment with meropenem and vancomycin, his headache resolved, inflammatory markers normalised, and tissue culture results from a new biopsy were negative.
 
Despite the apparent clinical resolution, interval MRI 8 weeks after cessation of treatment showed disease progression. There was new right-sided contrast enhancement in the nasopharynx with extension to the right carotid space, hypoglossal canal, and petrous apex. The patient was soon re-hospitalised with right temporal headache and bilateral vocal cord palsy. Transsphenoidal CT-guided biopsy was performed on the clivus and overlying mucosa and results were still benign. Culture results were similar to those previously and inflammatory markers were again elevated. He was given a second course of antibiotics and had a prompt clinical response.
 
Discussion
Three patients were referred to our department with intractable headache, facial pain, or otalgia, some of the most common presenting complaints of SBO along with cranial nerve deficits.1 These differ markedly to those of NPC: blood-stained nasal discharge, unilateral conductive hearing loss, and cervical lymphadenopathy. Cranial nerve palsies suggest local invasion. Singh et al2 recommend that SBO be suspected if patients with treated malignant otitis externa present with persistent headache, otitis media with effusion, and cranial nerve deficits without a mucosal lesion in the nasopharynx, but there are no internationally recognised diagnostic criteria and recommendations differ.
 
The diagnostic dilemma occurs in the physical findings on initial examination. A unilateral otitis media with effusion in Southeast Asian adults (Cases 1 and 2) is presumed to be NPC until proven otherwise. Endoscopic findings of a bulging nasopharynx further raise the alarm, even in the absence of an obvious mucosal lesion. At this point, regardless of co-morbidities, symptoms, presence or absence of nerve palsies, efforts should be made to confirm or exclude mucosal or submucosal malignancy before settling on a diagnosis of SBO.
 
The key to differentiating malignancy from infection is the result of tissue biopsy. Simple bedside punch biopsies of the visibly abnormal mucosa are usually adequate to obtain histological confirmation of NPC. In our cases, only vague bulging of the nasopharynx was evident. Negative results led to more invasive procedures to obtain deeper samples or down to the clivus. There is no established recommendation for use of intraoperative image-guided biopsy in this regard. This method attempted to maximise the yield of abnormal tissue to exclude with certainty any presence of malignancy.
 
Negative plasma EBV DNA level, in view of its high negative predictive value for endemic NPC, is another reason to exclude NPC. Inflammatory markers were raised in all our patients. Serial blood ESR level is also a useful marker for disease monitoring as it rapidly normalises with disease resolution3 but rises again with disease relapse.
 
Imaging played a key diagnostic role. Although CT can detect osseous destruction, these bony changes are a rather late phenomenon. In comparison, MRI offers higher soft tissue resolution, allowing delineation of anatomical location and soft tissue involvement.3 The MRI images in our cases typically showed gadolinium-enhanced signals at the nasopharynx, involving the clivus, petrous apex, skull base foramina, and parapharyngeal spaces on T1-weighted images. Images were suggestive of neoplasm, described by radiologists as “space occupying lesions” and “aggressive lesions with erosion/invasion of surrounding structures”. This further highlights the importance of histological correlation.
 
In conclusion, SBO is a rare disease that can masquerade as NPC. Although the two diseases warrant entirely different treatment modalities, it remains difficult to confidently differentiate one from the other during diagnosis. A holistic consideration of the patient’s clinical picture, and histological and microbiological results are essential for correct diagnosis.
 
Author contributions
All authors contributed to the design, acquisition of data, analysis of data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
All patients were treated in accordance with the Declaration of Helsinki. All patients provided informed consent for all procedures and for the publication of non-identifiable information.
 
References
1. Sokołowski J, Lachowska M, Karchier E, Bartoszewicz R, Niemczyk K. Skull base osteomyelitis: factors implicating clinical outcome. Acta Neurol Belg 2019;119:431-7. Crossref
2. Singh A, Al Khabori M, Hyder MJ. Skull base osteomyelitis: diagnostic and therapeutic challenges in atypical presentation. Otolaryngol Head Neck Surg 2005;133:121‑5. Crossref
3. van Kroonenburgh AM, van der Meer WL, Bothof RJ, van Tilburg M, van Tongeren J, Postma AA. Advanced imaging techniques in skull base osteomyelitis due to malignant otitis externa. Curr Radiol Rep 2018;6:3. Crossref

Anaphylaxis after surgical excision of subcutaneous infection with parasitic Dirofilaria: a case report

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Anaphylaxis after surgical excision of subcutaneous infection with parasitic Dirofilaria: a case report
Brian WC Luk, MB, BS; CN Cheung, MB, ChB, FHKAM (Orthopaedic Surgery); YF Chan, MB, BS, FHKAM (Orthopaedic Surgery)
Department of Orthopaedics and Traumatology, Pok Oi Hospital, Hong Kong
 
Corresponding author: Dr Brian WC Luk (lukwingchung@gmail.com)
 
 Full paper in PDF
 
Case report
In January 2018, a 21-year-old man with good past health presented with a 2-week history of left forearm painless lump. He had no fever. The lump was 30 mm in diameter with no evidence of inflammation. Preoperative diagnosis was a sebaceous cyst and preoperative blood tests were not routinely performed.
 
Surgical excision was performed under local anaesthesia with lidocaine and application of a tourniquet. Intra-operatively, a whitish-yellowish 25-mm subcutaneous nodule surrounded by dense adhesions without a definite border was removed. The nodule was firm and multi-lobulated with multiple feeding vessels. Although en bloc excision with a 5-mm margin was attempted, the dense fibrous mass was partially breached during dissection due to scarring.
 
After tourniquet release, the patient developed flushing, dizziness, diarrhoea, hypotension, and sinus tachycardia. He had no respiratory distress but the clinical diagnosis was anaphylactic shock. He was stabilised with fluid resuscitation and intravenous adrenaline. Laboratory tests showed an elevated white blood cell count (WBC) at 13.6 × 109/L (reference range: 3.9-10.7 × 109/L), neutrophil predominance at 85.9% (reference: 38%-76%), and low eosinophil count of only 0.027 × 109/L (reference: <0.45 × 109/L) and 0.2% of total WBC. Blood tests were otherwise unremarkable. Serum mast cell tryptase level was 46.2 μg/L immediately after surgery but dropped to 3.3 μg/L after 24 hours. Erythrocyte sedimentation rate or C-reactive protein were not measured. The patient remained well and was discharged home the next day.
 
The patient had no known history of allergy and skin allergy test for exposed agents including lidocaine was negative. On further questioning, he revealed regular contact with horses located in a countryside barn but no contact with other animals. He reported skin erythema (Fig 1) prior to swelling onset but had presumed this was due to a mosquito bite.
 

Figure 1. Clinical photograph of a 21-year-old patient with dirofilariasis showing the development of skin swelling on the left proximal volar forearm after the onset of erythema
 
Microscopy of the nodule revealed a piece of fibro-fatty tissue with mixed inflammatory cell infiltrate and dense eosinophilic infiltrate (Fig 2a), and a 0.72 mm × 0.29 mm fragment of degenerated parasite rimmed by foamy histiocytes (Fig 2b). There was no evidence of malignancy. The surgical margin measured from the edge of the surrounding granulomatous inflammation to the closest edge of the excised specimen was 0.82 mm. Further molecular study by polymerase chain reaction and DNA sequencing based on Filarioidea cytochrome oxidase subunit I (cox1) and specific 12S ribosomal RNA (12S rRNA) gene revealed the parasite to be Dirofilaria hongkongensis.1
 

Figure 2. Histopathological results from the same patient showing (a) degenerated parasite with ghost outline of the muscular layer and tubular structure, measuring 0.72 mm × 0.29 mm (haematoxylin and eosin, ×100) and (b) mixed inflammatory cell infiltrate with dense eosinophilic infiltrate (haematoxylin and eosin, ×400)
 
The patient remained symptom-free and differential WBC and C-reactive protein were normal at 6 months after surgery. No antiparasitic therapy was deemed necessary by microbiologists.
 
Discussion
Dirofilaria hongkongensis has been proposed as a novel species causing zoonotic filariasis in humans and is a possible cause of unresolved subcutaneous nodules in Hong Kong.2 This is the first reported case worldwide of anaphylactic shock following excision of subcutaneous dirofilariasis in a human.
 
Zoonotic filariae are transmitted to humans through the bite of an infected arthropod such as mosquitoes. However, they cannot grow to maturity in accidental hosts such as humans.3 The pathogenesis is localised foreign body reaction around a moribund parasite. The absence of a host inflammatory response in the asymptomatic period suggests death of the worm due to an unfavourable host environment, rather than host immunity.3 Asymptomatic survival and growth of the parasite may continue for ≥6 months. The lesion becomes clinically noticeable due to granulomatous reaction with tissue scarring and can present as a subcutaneous or ocular lesion, and rarely as lymphadenopathy and nodules in deeper tissues such as the lungs. In our patient, the subcutaneous dirofilariasis presented as a painless lump in his forearm, without any symptoms or signs of inflammation. The patient reported some skin erythema prior to the onset of the swelling. The erythema could have been caused by a mosquito bite, which is a possible route of parasite transmission. The absence of pain, warmth, or erythema over the mass would suggest the parasite did not trigger a significant inflammatory response in our patient. After the parasite’s death, the remaining material could be shielded off from the host tissue by a dense fibrous tissue envelope, producing a lump which was otherwise asymptomatic.
 
Careful history taking may reveal exposure to animals. Subcutaneous infections are small (0.5-1.5 cm) and discrete. Pain or sense of a moving worm may be present. Blood tests for eosinophilia and elevated inflammatory markers might be useful, but the absence of systemic inflammation is common3 and blood test results may be unremarkable. In our patient, blood tests were not taken preoperatively, as the clinical impression of the mass was a sebaceous cyst, with the absence of signs of inflammation. Postoperative blood tests showed neutrophilia instead of eosinophilia, but the results were likely affected by the anaphylaxis.
 
Among around 40 species of Dirofilaria, D immitis and D repens account for most cases of infection in humans. Dirofilaria immitis is commonly known as “dog heartworm” and has a cosmopolitan distribution. Hou et al4 reported seropositivity in 30.6% of stray dogs and 15.6% of domestic dogs in north-eastern China. Wang et al5 reported a 0% to 7.4% seroprevalence in dogs in coastal cities in south-eastern China. Dirofilaria repens is prevalent worldwide including Southeast Asia. Dirofilaria hongkongensis was first proposed as a distinct species in 2012, following three cases of human infection.2 In stray dogs in Hong Kong, the seroprevalence of D hongkongensis is 3%,2 and that of D immitis is 10%.6
 
Molecular study in nucleotide sequencing of cytochrome oxidase subunit 1 (cox1) gene and the 12S ribosomal RNA (12S rRNA) gene is useful in the identification of Dirofilaria species, taking reference from GenBank data. The cox1 gene and 12S rRNA gene specific to D hongkongensis were identified (GenBank accession number NC_031365). Simpler diagnostic tests would be less reliable; for example, morphological identification depends on the quality of histopathological specimen, and in our case only parasitic fragments were found. Retrospective molecular study could also be performed on the stored specimen for epidemiological studies.
 
Parasitic materials are foreign antigens that may trigger a type I immunoglobulin E–mediated hypersensitivity reaction. Dirofilaria immitis extract can result in shock and elevated plasma histamine level in dogs,7 while hydatid cyst (Echinococcus spp) rupture has been associated with anaphylactic shock.8 We believe the partial breach of the parasitic tissue envelope during our surgical dissection led to contact of parasitic material with host tissue. This contact, in turn, caused the hypersensitivity reaction and anaphylactic shock in our patient.
 
We recommend complete en bloc excision of lesions suspected to be caused by dirofilariasis to prevent anaphylaxis, especially when surgeons encounter dense adhesions or multiple feeding vessels. Further study is required to ascertain the necessary margin of excision to avoid inadvertent breakage of the tissue envelope. Up to 75.4% of parasitised humans experience chronic urticaria.9 In our patient, the capsule was breached during dissection and sudden allergen release may have triggered the anaphylactic cascade. Antiparasitic medication is likely unnecessary if the parasite can be removed intact.
 
Anaphylactic shock can cause sudden haemodynamic collapse. It is characterised by acute onset of hypotension after allergen exposure, or the combination of cutaneous, cardiopulmonary or gastrointestinal manifestations.10 The importance of routine monitoring, timely detection and cardiopulmonary stabilisation cannot be overemphasised. Plasma tryptase or histamine level may serve as a diagnostic adjunct in doubtful cases. Fluid resuscitation, supplemental oxygen, and epinephrine injection are indicated as effective treatments of anaphylactic shock.
 
Author contributions
All authors contributed to the concept of study, acquisition and analysis of data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patient was treated in accordance with the Declaration of Helsinki. The patient provided verbal informed consent for publication of this de-identified case report, including clinical photos.
 
References
1. Dang TC, Nguyen TH, Do TD, et al. A human case of subcutaneous dirofilariasis caused by Dirofilaria repens in Vietnam: histologic and molecular confirmation. Parasitol Res 2010;107:1003-7. Crossref
2. To KK, Wong SS, Poon RW, et al. A novel Dirofilaria species causing human and canine infections in Hong Kong. J Clin Microbiol 2012;50:3534-41. Crossref
3. Eberhard ML. Zoonotic filariasis. In: Guerrant R, Walker D, Weller P, editors. Tropical Infectious Diseases: Principles, Pathogens, and Practice. 3rd ed. New York: Elsevier; 2011: 750-8. Crossref
4. Hou H, Shen G, Wu W, et al. Prevalence of Dirofilaria immitis infection in dogs from Dandong, China. Vet Parasitol 2011;183:189-93. Crossref
5. Wang J, Zhu X, Ying Z, et al. Prevalence of Dirofilaria immitis infections in dogs and cats in Hainan Island/Province and three other coastal cities of China based on antigen testing and PCR. J Parasitol 2019;105:199-202. Crossref
6. Wong SS, Teng JL, Poon RW, et al. Comparative evaluation of a point-of-care immunochromatographic test SNAP 4DX with molecular detection tests for vector-borne canine pathogens in Hong Kong. Vector Borne Zoonotic Dis 2011;11:1269-77. Crossref
7. Kitoh K, Katoh H, Kitagawa H, Nagase M, Sasaki N, Sasaki Y. Role of histamine in heartworm extract-induced shock in dogs. Am J Vet Res 2001;62:770-4. Crossref
8. Khanna P, Garg R, Pawar D. Intraoperative anaphylaxis caused by a hepatic hydatid cyst. Singapore Med J 2011;52:e18-9.
9. Minciullo PL, Cascio A, Gangemi S. Association between urticaria and nematode infections. Allergy Asthma Proc 2018;39:86-95. Crossref
10. Simons FE, Ardusso LR, Bilò MB, et al. World allergy organization guidelines for the assessment and management of anaphylaxis. World Allergy Organ J 2011;4:13-37. Crossref

Combined interstitial laser cauterisation of placental anastomosis and intrauterine intracardiac transfusion following monochorionic co-twin demise: a case report

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Combined interstitial laser cauterisation of placental anastomosis and intrauterine intracardiac transfusion following monochorionic co-twin demise: a case report
PW Hui, MD, FRCOG; Mimi TY Seto, MB, BS, FHKAM (Obstetrics and Gynaecology); KW Cheung, MB, BS, FHKAM (Obstetrics and Gynaecology
Department of Obstetrics and Gynaecology, Queen Mary Hospital, Hong Kong
 
Corresponding author: Dr PW Hui (apwhui@hku.hk)
 
 Full paper in PDF
 
Case report
Single fetal demise in monochorionic pregnancy is associated with significant morbidity and mortality of the co-twin. We report the case of a 36-year-old nulliparous woman with unexpected single fetal demise in a monochorionic twin pregnancy diagnosed at 15 weeks and 4 days. She had been well since her last normal scan at 13 weeks and 3 days and no discordance in crown rump length or nuchal translucency thickness had been evident. Non-invasive prenatal testing for common aneuploidy screening was negative.
 
Ultrasound showed demise of one twin and scalp oedema and ascites in the surviving co-twin. Cardiothoracic ratio was elevated to 0.59 and tricuspid regurgitation was seen. Peak systolic velocity (PSV) of the middle cerebral artery (MCA) was increased to 2.18 multiples of median (MoM; 45.1 cm/s) and diastolic flow in the umbilical artery was absent. Cord insertion was velamentous and an arterial anastomosis was identified along the placental surface from the surviving twin to the placental cord insertion of the miscarried twin (Fig 1a and b).
 

Figure 1. Ultrasound images showing the presence of arterial placental anastomosis from the surviving twin to placental cord insertion of the miscarried twin, laser cauterisation and intracardiac transfusion. (a) Placental cord insertion of miscarried twin; (b) arterial vessel running from surviving twin to placental cord insertion of miscarried twin; (c) laser cauterisation of arterial anastomotic vessel; and (d) intracardiac transfusion with needle directed to right ventricle
 
The couple were counselled extensively on management options that included termination of pregnancy, conservative management, or active intrauterine interventions. Within 24 hours, the patient opted to undergo rescue transfusion for fetal anaemia and interstitial laser cauterisation of the placental anastomosis. Interstitial laser cauterisation was performed using an 18G spinal needle inserted transplacentally under ultrasound guidance to the anastomotic artery close to the cord insertion of the miscarried twin. A 780-μm laser fibre was advanced to 3 mm beyond the needle tip. Cauterisation was started with a 20-W diode laser and stepped up to 40 W for 100 s. Fetal heart pulsation was checked intermittently and was normal throughout. Cessation of blood flow was confirmed by colour Doppler ultrasonography (Fig 1c).
 
Intracardiac transfusion was performed the next day via a 22G needle directed to the fetal right ventricle (Fig 1d). Before the transfusion, haemoglobin was 4.2 g/dL and haematocrit was 10.5%. Transfusion of 4.5-mL O positive blood with haematocrit of 80% and irradiated for cytomegalovirus was uneventful. No bradycardia or pericardial effusion occurred. After the transfusion, haemoglobin was 12.6 g/dL and haematocrit was 37.2%. The MCA PSV was 48.7 cm/s (2.35 MoM) before the laser cauterisation and 50 cm/s (2.39 MoM) before the transfusion. It was reduced to 0.9 MoM after the transfusion. Other workup for fetal hydrops was negative.
 
The patient was monitored by weekly ultrasound for level of MCA PSV MoM and resolution of hydrops. Ascites disappeared 5 days after transfusion and MCA PSV was 1.3 MoM. Subcutaneous oedema subsided 1 week later and cardiothoracic ratio improved to 0.56. Fetal magnetic resonance imaging and detailed echocardiography at 22 weeks of gestation showed no abnormality. A loop of prominent bowel was noticed after 23 weeks of gestation. This was progressively dilated to 1.72 cm at 33 weeks of gestation. Peristalsis was present and bowel atresia was suspected. The patient went into preterm labour at 34 weeks and 2 days, delivering a baby boy weighing 1960 g. An area of cauterisation on the placental surface was evident next to the cord insertion of the miscarried twin (Fig 2).
 

Figure 2. Photograph of placenta showing an area of cauterisation (arrow) next to cord insertion of miscarried twin
 
Neonatal laparotomy on day 1 showed type 4 intestinal atresia. Resection of multiple atretic segments of the small bowel and primary anastomosis were performed. A second laparotomy was required on day 34 for resection of rectal atresia. Bowel function returned to normal afterwards. The baby had grade 1 intraventricular haemorrhage that resolved spontaneously and at age 5 months he had reached the appropriate developmental milestones.
 
Discussion
Single twin demise occurs in monochorionic pregnancies with twin-twin transfusion syndrome (TTTS) and selective intrauterine growth restriction but may also occur unexpectedly in pregnancies with no obvious complications.1 Feto-fetal haemorrhage through the placenta anastomosis leads to acute hypovolaemia and results in fetal anaemia, cerebral damage or death of the co-twin.1 2 Bowel and renal complications have also been reported.3 4 The present case illustrates successful intervention with a combination of interstitial laser to a placental anastomosis and intracardiac transfusion for a fetus at 15 weeks of gestation following monochorionic co-twin demise. The risk of co-twin demise and neonatal death is increased significantly in cases of single intrauterine fetal death in monochorionic pregnancies before 28 weeks.5 The surviving fetus is also at risk of other morbidity secondary to feto-fetal haemorrhage and hypoperfusion. Neurological damage affects almost 20% of co-twin survivors especially in fetuses demonstrating signs of fetal anaemia.1 6 This can be assessed by measuring MCA PSV.7 A value >1.55 MoM is suggested to be associated with a fivefold increase in the relative risk of cerebral injury.1
 
Rescue intrauterine transfusion has been proposed for an anaemic monochorionic survivor.8 The optimal timing of transfusion and impact on overall long-term outcome remain debatable. Feto-fetal haemorrhage may continue after intrauterine transfusion. It is, therefore, rational to conduct a sonographic search for placental anastomosis and perform cauterisation to cease further feto-fetal haemorrhage prior to intrauterine transfusion. In this case, an arterial vessel running towards the placental cord insertion of the miscarried twin was identified. With the presence of this anastomosis, rescue transfusion for the surviving fetus was unlikely to be effective as fetal anaemia could persist. Interstitial laser has been reported in cauterisation of feeding vessels in chorioangioma, fetal hyperechogenic lung lesion, and sacrococcygeal teratoma.9 Adopting the principle of intrauterine laser ablation in TTTS, a laser fibre was inserted via a 18G spinal needle transplacentally to cauterise this vessel under ultrasound guidance. A fetoscopic approach was not considered in view of the early gestation with an anterior placenta and absence of polyhydramnios. The energy requirement was guided by generation of an echogenic area around the fibre tip encompassing the vessel and cessation of blood flow on Doppler ultrasound.
 
Intracardiac fetal transfusion was performed because of the early gestation and difficult intravascular assess. This technique was first introduced in the late 1980s.10 Experience was gathered mainly from transfusing fetuses that were anaemic due to rhesus isoimmunisation or parvovirus infection reported as early as 16 weeks of gestation.11 12 13 Transient fetal bradycardia, haemopericardium, pericardial tamponade, and asystole are known complications.10 11 12
 
To the best of our knowledge, this is the first report of successful rescue of an anaemic co-twin survivor in a monochorionic pregnancy by combining laser to placental anastomosis and intracardiac transfusion as early as 15 weeks of gestation. Time was required for blood product preparation and also allowed the fetus to establish a new circulatory equilibrium following laser therapy when the ongoing transfusion was completed. It is of interest to note that fetal ascites may be an early presentation of bowel complications secondary to in-utero anaemia.3 Mesenteric ischaemia in monochorionic twins has been postulated to be related to haemodynamic alteration in case of co-twin demise, hypoperfusion, and/or hyperviscosity in TTTS or thromboembolic phenomenon after laser ablation. Ascites might also be an indication of circulatory insufficiency even in the absence of severe fetal anaemia. Evidence of transient cardiac failure has been reported after single fetal death in monochorionic twins and immediate intrauterine transfusion has been advocated to restore the circulatory volume.2
 
This case did not have features of TTTS although ascites, cardiomegaly, and tricuspid regurgitation were noted after co-twin demise and before intrauterine intervention. Although fetal anaemia was ascertained and hypovolaemic shock was likely present, it is not always possible to determine whether the ascites is secondary to circulatory insufficiency or bowel complications. As well as treating fetal anaemia, intrauterine transfusion may also correct circulatory insufficiency and restore cardiac function. The prompt intervention in this fetus led to complete resolution of the ultrasound abnormalities and possibly improved the neurological outcomes. The fetus required further monitoring for bowel complications that might only become obvious at a later stage of gestation.
 
In managing co-twin demise in a monochorionic pregnancy, assessment of the survivor requires detailed ultrasound examination to search for placental anastomosis, as well as an immediate assessment for signs of fetal anaemia and bowel or haemodynamic complications. Early laser cauterisation of placental anastomosis to control feto-fetal haemorrhage is an option combined with rescue intrauterine transfusion to prevent anaemia and circulatory insufficiency in the surviving twin.
 
Author contributions
All authors contributed to the concept of the study, acquisition of the data, and analysis of the data, and critical revision of the manuscript for important intellectual content. PW Hui drafted the manuscript. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patient was treated in accordance with the Declaration of Helsinki and provided informed consent for all procedures.
 
References
1. Lanna MM, Consonni D, Faiola S, et al. Incidence of cerebral injury in monochorionic twin survivors after spontaneous single demise: long-term outcome of a large cohort. Fetal Diagn Ther 2020;47:66-73. Crossref
2. Iwagaki S, Takahashi Y, Chiaki R, Asai K, Matsui M, Katsura D. Case of resuscitation from cardiac failure by intrauterine transfusion after single fetal death in monochorionic twin pregnancy. J Obstet Gynaecol Res 2019;45:2105-10. Crossref
3. Tan LN, Cheung KW, Philip I, Ong S, Kilby MD. Isolated ascites in a monochorionic twin after fetoscopic laser ablation is not necessarily secondary to recurrence or anaemia: bowel complications in twin-to-twin transfusion syndrome after fetoscopic laser ablation. Fetal Diagn Ther 2019;45:285-94. Crossref
4. Genova L, Sueters M, van Steenis A, Oepkes D, Steggerda SJ, Lopriore E. Renal failure after single fetal demise in monochorionic twins: incidence and description of a case. Fetal Diagn Ther 2014;35:302-5. Crossref
5. Mackie FL, Rigby A, Morris RK, Kilby MD. Prognosis of the co-twin following spontaneous single intrauterine fetal death in twin pregnancies: a systematic review and metaanalysis. BJOG 2019;126:569-78. Crossref
6. Mackie FL, Morris RK, Kilby MD. Fetal brain injury in survivors of twin pregnancies complicated by demise of one twin: a review. Twin Res Hum Genet 2016;19:262-7. Crossref
7. Senat MV, Loizeau S, Couderc S, Bernard JP, Ville Y. The value of middle cerebral artery peak systolic velocity in the diagnosis of fetal anemia after intrauterine death of one monochorionic twin. Am J Obstet Gynecol 2003;189:1320-4. Crossref
8. Quarello E, Stirnemann J, Nassar M, et al. Outcome of anaemic monochorionic single survivors following early intrauterine rescue transfusion in cases of feto-fetal transfusion syndrome. BJOG 2008;115:595-601. Crossref
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11. von Kaisenberg CS, Grebe S, Schleider S, Kuhling-von Kaisenberg H, Venhoff L, Meinhold-Heerlein I. Successful intrauterine intracardiac transfusion in monochorionic twins affected by parvovirus B19. Fetal Diagn Ther 2007;22:420-4. Crossref
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Novel diaphragmatic reconstruction technique for recurrent diaphragmatic hernia: a case report

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Novel diaphragmatic reconstruction technique for recurrent diaphragmatic hernia: a case report
Teddy HY Wong, MRCS; Simon CY Chow, FRCS; Peter SY Yu, MRCS; Jacky YK Ho, FRCS; Rainbow WH Lau, FRCS; Innes YP Wan, FRCS; Randolph HL Wong, FRCS
Division of Cardiothoracic Surgery, Department of Surgery, Prince of Wales Hospital, Hong Kong
 
Corresponding author: Dr Randolph HL Wong (wonhl1@surgery.cuhk.edu.hk)
 
 Full paper in PDF
 
Case report
A 51-year-old lady with a history of congenital diaphragmatic hernia repair during infancy presented to the emergency department with increasing abdominal pain and repeated vomiting. Posteroanterior chest plain radiograph revealed dilated small bowel loops in the right thoracic cavity. Computed tomography scan revealed two closely related small bowel loops trapped within a narrow hernia neck orifice across the diaphragm, suggestive of closed loop intestinal obstruction (Fig 1). Blood test results revealed metabolic acidosis and elevated lactate level.
 

Figure 1. Computed tomography showing large right diaphragmatic hernial defect (blue arrow)
 
Emergency laparotomy via a subcostal incision revealed a right-sided large diaphragmatic defect with bowel herniating into the thoracic cavity. Transabdominal reduction of the bowel was difficult owing to adhesion of bowel to the lung so an additional posterolateral thoracotomy was performed by a cardiothoracic team. Adhesiolysis was performed and the small bowel freed and reduced to the abdominal cavity via the transthoracic approach. Examination through the thoracotomy revealed minimal residual diaphragmatic tissue (Fig 2a). Primary closure was not possible and repair with a patch posed a technical challenge in the absence of sufficient residual diaphragmatic tissue to enable secure anchorage. For the anterolateral portion, multiple pledgetted 3-O sutures were passed through the intercostal space for anchorage (Fig 2b). A neo-diaphragm was reconstructed using a porcine dermal collagen implant of size 150 mm × 200 mm × 1 mm (PermacolTM; Medtronic, Minneapolis [MN], United States). The patch was then parachuted down to cover the defect and secured. A 4-cm flutter-valve patch was directed downwards and medially to avoid suturing and injury to the oesophagus and inferior vena cava (Fig 2c). We believe this design permits peristalsis of oesophageal content without causing stricture while also preventing future intestinal herniation.
 

Figure 2. Schematic diagram illustrating the novel diaphragmatic reconstruction. (a) Visual examination through the thoracotomy revealed the ribcage (black arrow) and residual diaphragmatic tissue (black arrowheads). (b) Multiple pledgetted 3-O sutures were passed through the intercostal space for anchorage of the anterolateral portion. Oesophagus is indicated by black arrow. (c) A 4-cm flutter-valve patch was directed downwards and medially to avoid suturing and injury to the reconstructed oesophagus and inferior vena cava. Inset: Alternate view showing downward flutter valve (yellow arrow)
 
Postoperatively the patient was prescribed total parenteral nutrition for 10 days and gradually tolerated a normal diet. A computed tomography scan at 10 days after surgery confirmed an intact neo-diaphragm with no recurrence of hernia. The patient was discharged home 13 days after surgery. She was well at follow-up examinations at 1 month and 12 months after surgery. Chest plain radiograph confirmed no recurrence of hernia (Fig 3).
 

Figure 3. Chest plain radiographs of the patient (a) before and (b) after surgical repair of the diaphragmatic hernia with neo-diaphragm
 
Discussion
Diaphragmatic hernia is a rare but serious condition associated with respiratory and gastrointestinal complications and increased mortality.
 
Surgical repair is the gold standard treatment to prevent complications. However, patients with a previously repaired congenital diaphragmatic hernia are more prone to respiratory complications during childhood and occasionally develop recurrences.1 However, the long-term success rate of repair is good with patients surviving well into adulthood with a normal life expectancy.
 
Surgical options for repair include a primary repair and a patch repair. A patch repair is associated with higher risks of complications and recurrence.2 However, for a hernia with large defects in which a primary repair is not possible, repair with surgical mesh (xenograft or synthetic) is an effective and safe method.3 In conventional patch repair, the hernia sac is repositioned and resected. The hernia defect is sized and the Permacol trimmed to cover the defect. The flap is then fixed to the remaining rim of diaphragmatic tissue with absorbable sutures.4 The lack of an adequate rim of tissue in our patient presented a unique challenge for construction of the neo-diaphragm relative to most instances of diaphragmatic hernia where a remnant of diaphragmatic tissue is present for anchorage. Although the pleura and adjacent chest wall offer good support for anchoring the neo-diaphragm posteriorly and anterolaterally, there is often a lack of strong tissue medially with consequent substantial risk of inadvertent injury to the oesophagus if sutures are placed too deeply. Travers et al5 reported an incidence of oesophageal injury up to 3.9% in their series of surgical repair of para-oesophageal hernia using porcine dermal collagen biologic mesh (Permacol). Innovative designs in the creation of the neo-diaphragm have been reported, but most studies have been in paediatric patients.6 The technique described in this case report is novel and has not been reported elsewhere. The design of a flutter valve mechanism in the reconstruction of the medial aspect of the neo-diaphragm serves to create a tension-free repair near the mediastinum and oesophagus while also creating a seal to separate the pleural cavity from the abdominal contents. No sutures were applied near the oesophagus or the medial side of the neo-diaphragm. This technique avoids inadvertent visceral injury and is currently our preferred technique of neo-diaphragm construction in patients with a large diaphragmatic defect and insufficient rim.
 
In our case, we utilised the acellular dermal matrix Permacol for hernia repair. Permacol is a cross-linked graft comprised of acellular collagen matrix. Compared with other collagen-based implants, it offers long-lasting dimensional stability and avoids loss of tensile strength as well as increased tissue laxity resulting in lower rates of recurrence. Acellular dermal matrix is a developing technology and studies have shown promising results for its efficacy.7
 
In conclusion, repair of diaphragmatic hernia with a xenograft composed of dermal collagen implant and a medial flutter-valve design is safe and effective. It avoids inadvertent injury to mediastinal structures while allowing satisfactory prevention of recurrence of diaphragmatic herniation of intestines.
 
Author contributions
Concept or design: All authors.
Acquisition of data: All authors.
Analysis or interpretation of data: All authors.
Drafting of the manuscript: THY Wong, SCY Chow, RHL Wong.
Critical revision of the manuscript for important intellectual content: All authors.
 
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patient was treated in accordance with the tenets of the Declaration of Helsinki. The patient provided written informed consent for all treatments and procedures and consent for publication.
 
References
1. Jancelewicz T, Chiang M, Oliveira C, Chiu PP. Late surgical outcomes among congenital diaphragmatic hernia (CDH) patients: why long-term follow-up with surgeons is recommended. J Pediatr Surg 2013;48:935-41. Crossref
2. Jancelewicz T, Vu LT, Keller RL, et al. Long-term surgical outcomes in congenital diaphragmatic hernia: observations from a single institution. J Pediatr Surg 2010;45:155-60. Crossref
3. Kuhn R, Schubert D, Wolff St, Marusch F, Lippert H, Pross M. Repair of diaphragmatic rupture by laparoscopic implantation of a polytetrafluoroethylene patch. Surg Endosc 2002;16:1495. Crossref
4. Lingohr P, Galetin T, Vestweber B, Matthaei H, Kalff JC, Vestweber KH. Conventional mesh repair of a giant iatrogenic bilateral diaphragmatic hernia with an enterothorax. Int Med Case Rep J 2014;7:23-5. Crossref
5. Travers HC, Brewer JO, Smart NJ, Wajed SA. Diaphragmatic crural augmentation utilising cross-linked porcine dermal collagen biologic mesh (Permacol) in the repair of large and complex para-oesophageal herniation: a retrospective cohort study. Hernia 2016;20:311-20. Crossref
6. Loff S, Wirth H, Jester I, et al. Implantation of a cone-shaped double-fixed patch increases abdominal space and prevents recurrence of large defects in congenital diaphragmatic hernia. J Pediatr Surg 2005;40:1701-5. Crossref
7. Buinewicz B, Rosen B. Acellular cadaveric dermis (AlloDerm): a new alternative for abdominal hernia repair. Ann Plast Surg 2004;52:188-94. Crossref

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