The following three cases highlight the potential serious consequences of trampolining.

A 27-year-old woman with good past health was admitted with left foot pain and swelling in July 2014. She fell with axial loading on an inverted and plantar-flexed left foot while trampolining. Physical examination showed bruising on the dorsum of her left foot with tenderness over the base of the first and second metatarsals. Range of movement was limited by pain. Subsequent X-ray showed widening of the Lisfranc joint with base avulsion (Fig a). Lisfranc fracture was diagnosed. Open reduction with screw and K-wire fixation were performed and a resting ankle-foot orthosis was given. On follow-up 2 weeks after surgery, sensation and circulation in the toes were good. Range of movement was still limited by pain, however. She was encouraged to move her ankle and toes, and to mobilise with heel-walking at 6 weeks postoperatively.

A 25-year-old swimming instructor with good past health was admitted for thoracolumbar back pain after jumping and falling from 1 metre while trampolining in August 2014. He landed on his upper back with his body flexed on a trampoline. On examination, there was local tenderness at the thoracolumbar junction. His power and sensation across L2 to S1 were normal, reflexes were present, and anal sensation and tone were intact. Lumbosacral spine X-ray showed collapsed T12 and L1 with local kyphosis of 25°. Computed tomographic scan was performed subsequently, detailing a two-column fracture of T12 and L1 with anterior wedging of 20% (Fig b). He was put on a rigid thoracolumbar orthosis for 8 weeks and prescribed analgesics. Close monitoring for further collapse was warranted. During follow-up, he had no complaints of pain or neurological symptoms. Follow-up X-ray of the lumbosacral spine was static.

A 22-year-old woman with good past health was admitted with left ankle pain and deformity after landing on a trampoline with plantar flexion and ankle inversion in August 2014. Physical examination revealed a deformed left ankle joint in medial rotation and plantar flexion. There was bruising over the left foot dorsum and marked tenderness over the whole ankle joint line. She could move her toes only slightly. Distal circulation was intact, but sensation was reduced over her left foot and toes. X-ray of the left ankle showed posterior talus dislocation without definite fracture (Fig c). Closed reduction was performed under sedation and a short leg slab was applied. Post-reduction X-ray showed a congruent ankle joint. Computed tomography showed no fracture. Magnetic resonance imaging of the left ankle showed small cortical fractures at the medial body of talus and posterior aspect of distal talus, complete tear of the calcaneofibular ligament and anterior talofibular ligament, and a partial thickness tear of the deep deltoid ligament. Immobilisation with a short leg cast is planned after oedema has subsided.

In Hong Kong, trampolining was once a part of school physical education classes since it improves motor control and increases physical activity.1 However, following a trampoline incident in 1991 that resulted in quadriplegia,2 its popularity dwindled. Since the opening of the first trampoline park in Hong Kong in late July 2014,3 an increase in the number of trampoline-related injuries requiring admission to our department has been noted. Eight trampoline-related admissions were observed in less than 2 months. It has been estimated that the incidence of injuries that required admission to our unit was 1.9 per 10 000.4 The reasons of admission included Lisfranc fracture, vertebral fracture, ankle dislocation, anterior cruciate ligament tear of the knee, and neck and back sprains (Table). All patients were previously healthy but had no trampolining experience when they attended the indoor trampoline park for recreation and injured themselves while landing on a trampoline mat. Physicians and the general public need to be aware that trampolining can result in significant injuries, leading to acute hospital admission or even early surgical attention.

In a New Zealand study, most trampoline injuries occurred on home trampolines.5 With its limited space, home trampolining is not popular in Hong Kong, thus there is a lack of local studies. Nonetheless since the recent opening of a trampoline park in our cluster, the awareness of trampoline-related injuries has risen rapidly. In less than 2 months, eight patients were admitted for trampoline-related injuries. Their age ranged from 22 to 48 years, with seven aged between 22 and 30 years. In overseas studies, the highest incidence of injury occurred in patients under 20 years of age.5 6 This is related to accessibility to home trampolines.

Nysted and Drogset1 evaluated a total of 551 injuries, among which 292 cases were secondary to awkward landing on the trampoline1 in comparison with seven out of eight cases observed locally. The second and third most common mechanism of injury was falling off the trampoline and collision with another person, respectively.1 Falling off the trampoline is not possible in our setting since there are multiple interconnected trampolines that are levelled with a padded ground. The fourth commonly reported injury was caused by performing a somersault (11%)1 on the trampoline which was the cause of injury in our eighth patient. In another study by Alexander et al,7 a similar trend is seen. A majority of injuries (42%) were due to landing badly on the trampoline. Injuries from the frame/springs, presence of multiple jumpers, and getting on/off constituted 19%, 10% and 2% of all trampoline injuries, respectively. In short, serious injuries can happen even when landing on a soft surface such as a trampoline mat where participants may be less cautious.

In our report, there was a lack of injuries involving the upper extremities, contrary to the findings of overseas studies. This could be skewed by the small sample size as well as the nature of trampolining; untrained adults tend to be more conservative and land axially on their feet. Hence the majority of our cases involved the lower extremities (50%), and is congruent with the findings of Hume et al5 and Nysted and Drogset1 (46% and 45%, respectively). Another important point to note is that injuries involving the spine are not uncommon (25%).

Regarding the types of injury, fractures constituted a significant proportion of injuries in the studies of Nysted and Drogset1 and Chalmers et al8 (36% and 68%, respectively), and was also the case in our study (37.5%). A small proportion of local injuries were dislocation, which is observed in the same studies.1 8

In addition to regular maintenance and a readily available first-aid kit, a number of measures can be taken that may lower the injury rates. Most importantly, participants should be verbally briefed by the facility provider about the risks and dangers of trampoline use.9 For example, only one participant should be on a trampoline mat at any given time.9 Black and Amadeo10 emphasised the importance of multiple jumpers as a risk factor for injuries due to the elastic recoil generated by a larger person jumping on the mat.

In order to familiarise participants with the elasticity of a trampoline, trampolines of lower elasticity should be provided for warm-up. This is a common practice in formal training,11 and may reduce the chance of awkward landing due to motor incoordination. Another suggestion is to restrict beginners from performing complex movements such as somersaults and flips.9 To achieve this, the provider may provide a separate area for advanced participants. It is important to note that padding to cover frames has not been shown to reduce injuries.7 Injury rates should be monitored8 closely by the provider so that the effectiveness of safety measures can be evaluated.

Injuries that did not require hospital admission were not included, such as those in patients who presented to general practitioners or who were discharged from the emergency department. Furthermore, this report can only include cases that occurred up to the time of writing. This may underestimate the problem and lead to inaccurate interpretation. It is also difficult to draw comparisons with epidemiological data from other countries where the majority of injuries arise from home trampoline use and not from trampoline parks. Lastly, although trampolining may be perceived as a dangerous physical activity, this may not be the case; the risk of injury is not high compared with other physical activities.

We thank Dr Siu-ho Wan for encouragement, guidance, and assistance throughout the preparation of the case reports.

1. Nysted M, Drogset JO. Trampoline injuries. Br J Sports Med 2006;40:984-7. Crossref

2. Tang SP. I want euthanasia [In Chinese]. Hong Kong: Joint Publishing (HK) Co Ltd; 2007.

3. South China Morning Post. Hong Kong’s first trampoline park, Ryze, is bound to be fun. Available from: http://yp.scmp.com/news/sports/article/90339/hong-kongs-first-trampoline-park-ryze-bound-be-fun. Accessed 4 Sep 2014.

4. South China Morning Post. Trampoline centre Ryze proves a summer hit with Hong Kong youth. Available from: http://www.scmp.com/news/hong-kong/article/1565201/trampoline-centre-ryze-proves-summer-hit-hong-kong-youth. Accessed 26 Feb 2014.

5. Hume PA, Chalmers DJ, Wilson BD. Trampoline injury in New Zealand: emergency care. Br J Sports Med 1996;30:327-30. Crossref

6. Hammer A, Schwartzbach AL, Paulev PE. Trampoline training injuries—one hundred and ninety-five cases. Br J Sports Med 1981;15:151-8. Crossref

7. Alexander K, Eager D, Scarrott C, Sushinsky G. Effectiveness of pads and enclosures as safety interventions on consumer trampolines. Inj Prev 2010;16:185-9. Crossref

8. Chalmers DJ, Hume PA, Wilson BD. Trampolines in New Zealand: a decade of injuries. Br J Sports Med 1994;28:234-8. Crossref

9. Council on Sports Medicine and Fitness, American Academy of Pediatrics, Briskin S, LaBotz M. Trampoline safety in childhood and adolescence. Pediatrics 2012;130:774-9. Crossref

10. Black BG, Amadeo R. Orthopedic injuries associated with backyard trampoline use in children. Can J Surg 2003;46:199-201.

11. USA Gymnastics. Basic trampoline—the beginning steps. Available from: https://usagym.org/pages/home/publications/technique/2000/3/basictrampoline.pdf. Accessed 8 Sep 2014.

A 20-year-old man who worked as a car mechanic and enjoyed good health presented to United Christian Hospital in Hong Kong in August 2013 after collapsing suddenly at work. Ventricular arrhythmia was detected by ambulance men and defibrillation was performed 3 times with an automated external defibrillator. He was then transferred to the emergency department of the same hospital where he was observed to have persistent ventricular tachycardia and fibrillation. Advanced cardiac life support was continued, repeated defibrillation was performed and spontaneous circulation was restored 53 minutes later when he was then intubated.

Initial electrocardiogram after successful resuscitation showed diffuse ST elevation over the chest leads (Fig 1). Echocardiogram revealed poor left ventricular systolic function with global hypokinesia. Ad-hoc cardiac catheterisation was carried out. There was no coronary lesion and the patient was transferred to the intensive care unit (ICU) for therapeutic hypothermia.

On arrival in ICU, the patient had a high fever up to 39.7°C. Blood pressure was normal on low-dose inotropes and pulse rate was 140 beats/minute. Glasgow Coma Scale score was 2 for eye opening, 1 for verbal response, and 1 for motor response. His pupils were equal and reactive, and bilateral plantar reflexes were equivocal. Frothy sputum was evident from the endotracheal tube but physical examination was otherwise unremarkable.

Initial blood tests revealed elevated white cell count (WCC) of 25.1 x 10⁹ /L (reference range [RR], 3.9-9.3 x 10⁹ /L), neutrophilia of 21.6 x 10⁹ /L (RR, 1.8-6.2 x 10⁹ /L), and normal lymphocyte count of 2.9 x 10⁹ /L (RR, 1.0-3.2 x 10⁹ /L). Haemoglobin level and platelet count were normal. He had mild renal and liver impairment with urea 8.2 mmol/L (RR, 2.8-8.1 mmol/L), and creatinine 138 µmol/L (RR, 62-106 µmol/L). Sodium and potassium levels were normal and alanine transferase (ALT) was 152 IU/L (reference level [RL], <41 IU/L). Creatinine kinase was 6439 IU/L (RR, 39-308 IU/L), and troponin I was 12 886 ng/L (RL, ≤14 ng/L). Initial urine toxic screening was negative. His first chest X-ray (CXR) showed right upper lobe consolidation, but repeated CXR the next morning showed almost complete resolution. Initial computed tomography (CT) of the brain was unremarkable.

Amoxicillin/clavulanate was started to cover aspiration pneumonia. Therapeutic hypothermia for neuroprotection and continuous veno-venous haemofiltration for acute kidney injury were commenced. On day 4 the patient developed convulsions and repeated CT brain showed diffuse cerebral oedema. An electroencephalogram showed diffuse encephalopathy compatible with severe hypoxic-ischaemic insult. The patient remained in a vegetative state and a tracheostomy was performed. He had repeated episodes of ventilator-associated pneumonia that were unresponsive to multiple regimens of antibiotics and finally succumbed on day 24 of admission.

Serology for viral studies was all negative. Nonetheless, paired serology for Mycoplasma pneumoniae on 26 August 2013 and 4 September 2013 showed a 4-fold decrease in antibody titres from 1:160 to 1:40, suggestive of recent M pneumoniae infection. Postmortem examination showed diffuse lymphocytic infiltrates and extensive myocardial necrosis within myocardial fibres (Fig 2). Reversetranscriptase polymerase chain reaction (RT-PCR) for M pneumoniae on bilateral lung tissue and myocardium were negative.

A 57-year-old security guard with a history of infrequent asthma attacks but no regular follow-up attended the emergency department of United Christian Hospital in September 2013 with fever, chills, and rigors. He also complained of a new-onset maculopapular rash over the trunk and limbs that developed 1 day prior to admission. He volunteered that he was constantly exposed to insect bites due to the close proximity of rural areas to his working environment.

After admission to the medical ward, he developed a high fever of 40.3°C. Blood pressure was normal and pulse rate was 110 beats/minute. Oxygen saturation could be maintained on low-flow oxygen. Physical examination of the cardiovascular system, chest, and abdomen was normal but a maculopapular rash compatible with erythema multiforme over the back, lower abdomen, and bilateral lower limbs was observed. No eschar could be seen.

Initial investigations revealed the following: elevated WCC at 22.1 x 10⁹ /L, neutrophilia of 21 x 10⁹ /L, and lymphopenia of 0.2 x 10⁹ /L. The haemoglobin level was 117 g/L (RR, 135-173 g/L) and platelet count was 79 x 10⁹ /L (RR, 160-420 x 10⁹ /L). The clotting profile was mildly deranged, with international normalised ratio of 1.3. He also had mild renal and liver impairment: creatinine 111 µmol/L, ALT 74 IU/L, and aspartate aminotransferase 101 IU/L. Initial CXR did not reveal any consolidative changes.

Amoxicillin/clavulanate was commenced but the patient’s condition deteriorated with development of septic shock that required high-dose inotropes, type I respiratory failure requiring high-flow oxygen, acute kidney injury, and disseminated intravascular coagulopathy despite change in antibiotic therapy to piperacillin/tazobactam and azithromycin soon after admission. He was transferred to ICU on day 3 of admission and required intubation due to aspiration. Antibiotics were changed to piperacillin/tazobactam and doxycycline. His condition gradually improved and he was successfully extubated and weaned off all inotropes. The skin rash also resolved spontaneously and repeated biochemistry tests revealed complete resolution of renal and liver derangement.

Skin biopsy was not performed. The Widal test and Weil-Felix tests were all negative. Paired serology of M pneumoniae showed a 4-fold rise in antibody titres from 1:<10 to 1:40, with confirmation of M pneumoniae infection. Viral serology for rubella and salmonella was not increased.

We report two cases of M pneumoniae infection that presented with extrapulmonary symptoms and no significant respiratory involvement. Mycoplasma pneumoniae usually infects the upper and lower respiratory tract. Up to 50% of patients develop only mild upper respiratory tract symptoms such as cough, sore throat, malaise, and only 3% to 10% of patients develop pneumonia.1

Approximately 25% of patients infected with M pneumoniae develop extrapulmonary complications. This can happen before, during, or after the onset of or even in the absence of respiratory symptoms.1 An autoimmune reaction has been suggested as the pathogenesis of many of these extrapulmonary complications.1 The presence of organisms at an extrapulmonary site, however, suggests that direct invasion is also an important mechanism.2 3

The extrapulmonary manifestations associated with M pneumoniae may be neurological, cardiac, dermatological, musculoskeletal, haematological, and gastro-intestinal.4 Of these, neurological and dermatological symptoms are recognised as among the most common extrapulmonary manifestations of M pneumoniae infection.1 4

A wide range of dermatological manifestations has been described in patients with M pneumoniae infection. Mild symptoms include a maculopapular or vesicular rash.5 Erythema multiforme and Stevens-Johnson syndrome have a strong association with M pneumoniae infection.4 6 7 8

The patient in case 2 presented with sepsis and erythema multiforme. He was not prescribed any medication associated with erythema multiforme. Since a list of infective causes of erythema multiforme had been excluded by serology tests, his skin manifestation was most likely due to M pneumoniae infection.

Cardiac involvement is regarded as an uncommon complication of M pneumoniae infection.1 Pericarditis, myocarditis or pericardial effusion with or without tamponade effect have been described.1 It is more commonly found in adults than in paediatric patients.9 Fortunately, the outcome is generally good. Only a minority of patients had long-term sequelae and mortality is rare.10

Myocarditis associated with M pneumoniae infection that presents with ventricular arrhythmia as in case 1 is rare. We excluded other common causes of ventricular arrhythmia by initial blood tests, toxic screening, cardiac catheterisation, and CT brain. A 4-fold decrease in antibody titre of paired sera confirmed recent M pneumoniae infection. Autopsy results showed lymphocytic myocarditis. It is plausible, although not confirmative, that M pneumonia–associated myocarditis due to direct invasion of M pneumoniae cannot be shown by RT-PCR. Other differential diagnoses of lymphocytic myocarditis such as viral myocarditis were excluded by viral serology.

In addition to the diverse clinical manifestations, clinicians should also be aware of widespread macrolide resistance of M pneumoniae in Asia, including Hong Kong.11 High rates of macrolide resistance of up to 70% to 80% have been reported in China and Japan.12 13 14 Prompt adjustment of antibiotics to cover atypical pathogens is essential to successful treatment, as in our second patient. Consideration of alternatives such as doxycycline or fluoroquinolones as empirical treatment of atypical pathogens in areas with high rates of resistance may be appropriate.14

In conclusion, although M pneumoniae most commonly presents with respiratory tract symptoms, extrapulmonary manifestations are not uncommon. Clinicians should be aware of variable clinical presentations of M pneumoniae and macrolide resistance in our locality.

1. Waites KB, Talkington DF. Mycoplasma pneumoniae and its role as a human pathogen. Clin Microbiol Rev 2004;17:697-728. Crossref

2. Kasahara I, Otsubo Y, Yanase T, Oshima H, Ichimaru H, Nakamura M. Isolation and characterization of Mycoplasma pneumoniae from cerebrospinal fluid of a patient with pneumonia and meningoencephalitis. J Infect Dis 1985;152:823-5. Crossref

3. Saïd MH, Layani MP, Colon S, Faraj G, Glastre C, Cochat P. Mycoplasma pneumoniae–associated nephritis in children. Pediatr Nephrol 1999;13:39-44. Crossref

4. Sánchez-Vargas FM, Gómez-Duarte OG. Mycoplasma pneumoniae—an emerging extra-pulmonary pathogen. Clin Microbiol Infect 2008;14:105-17. Crossref

5. Baum SG. Mycoplasma pneumoniae infection in adults. Available from: http://www.uptodate.com/contents/mycoplasma-pneumoniae-infection-in-adults? source=search_result&search=Mycoplasma+pneumoniae+infection+in+adults.&selectedTitle=1%7E116. Accessed Aug 2015.

6. Vanfleteren I, Van Gysel D, De Brandt C. Stevens-Johnson syndrome: a diagnostic challenge in the absence of skin lesions. Pediatr Dermatol 2003;20:52-6. Crossref

7. Vargas-Hitos JA, Manzano-Gamero MV, Jiménez-Alonso J. Erythema multiforme associated with Mycoplasma pneumoniae. Infection 2014;42:797-8. Crossref

8. Rock N, Belli D, Bajwa N. Erythema bullous multiforme: a complication of Mycoplasma pneumoniae infection. J Pediatr 2014;164:421. Crossref

9. Formosa GM, Bailey M, Barbara C, Muscat C, Grech V. Mycoplasma pneumonia—an unusual cause of acute myocarditis in childhood. Images Paediatr Cardiol 2006;8:7-10.

10. Paz A, Potasman I. Mycoplasma-associated carditis. Case reports and review. Cardiology 2002;97:83-8. Crossref

11. Ho PL, Wong SY, editors. Reducing bacterial resistance with IMPACT—Interhospital Multi-disciplinary Programme on Antimicrobial ChemoTherapy. 4th ed. Hong Kong SAR: Centre for Health Protection; 2012.

12. Yin YD, Cao B, Wang H, et al. Survey of macrolide resistance in Mycoplasma pneumoniae in adult patients with community-acquired pneumonia in Beijing, China [in Chinese]. Zhonghua Jie He He Hu Xi Za Zhi 2013;36:954-8.

13. Eshaghi A, Memari N, Tang P, et al. Macrolide-resistant Mycoplasma pneumoniae in humans, Ontario, Canada, 2010-2011. Emerg Infect Dis 2013;19(9). doi: 10.3201/eid1909.121466. Crossref

14. Okada T, Morozumi M, Tajima T, et al. Rapid effectiveness of minocycline or doxycycline against macrolide-resistant Mycoplasma pneumoniae infection in a 2011 outbreak among Japanese children. Clin Infect Dis 2012;55:1642-9. Crossref

Click here to watch a video clip showing robotic-assisted laparoscopic Mitrofanoff appendicovesicostomy

The da Vinci Surgical System for robotic-assisted laparoscopic surgery was approved by the US Food and Drug Administration in 2000.1 Since its introduction, various types of operations have been successfully performed by robotic-assisted laparoscopic surgery. This technique, however, is limited by its lack of flexibility in the operative field and the size of paediatric patients. Therefore, its use is mainly confined in adult patients. Here, we describe the use of robotic-assisted laparoscopic Mitrofanoff appendicovesicostomy in a paediatric patient with detrusor underactivity and sensory neuropathy.

In September 2009, a 12-year-old girl with hereditary sensory neuropathy presented to Queen Mary Hospital with overflow incontinence. She had a rare hereditary sensory neuropathy, which resulted in no pain sensation and no sensation of bladder fullness. As well as sensory neuropathy, she had mild mental retardation, and studied in a special school.

She presented with overflow incontinence, difficulty in initiating voiding, long voiding time, and large volume of post-void residual urine. The results of investigations—including renal function test, ultrasound of the urinary system, and magnetic resonance imaging of the lumbosacral spine—were normal. Video urodynamics revealed poor bladder sensation despite high detrusor pressure, low voiding detrusor pressure, and incomplete emptying. The overall impression was detrusor underactivity.

The initial treatment plan was for transurethral clean intermittent urinary catheterisation (CIC) to be performed regularly by the patient’s caregiver. Because of the patient’s mental status and uncooperability, however, she could not tolerate CIC. After thorough discussion, the patient’s parents agreed to the patient undergoing Mitrofanoff appendicovesicostomy.

The operation was performed in a Trendelenburg position. A 12-mm camera port was placed at the circumumbilical position. Two 8-mm working ports were placed one each at the left lower quadrant and right upper quadrant. A 5-mm assistant port was placed at the epigastric area, mainly for bowel retraction and passing sutures (Fig).

Preoperative intravenous antibiotics of amoxicillin-clavulanic acid 30 mg/kg were administered. A urinary catheter was inserted under aseptic conditions. The appendix was mobilised with its mesentery. However, the appendix and its mesentery appeared to be relatively short (appendix was approximately 6 cm and mesentery was approximately 4 cm) in this patient so the right colon was mobilised en bloc up to the hepatic flexure to create mobility of the appendix and its mesentery.

Initial mobilisation of the right colon and bladder was performed with conventional laparoscopy. The robotic system was docked in to perform the anastomosis between the bladder and appendix.

The urinary bladder was partially infused with normal saline via the urinary catheter. The tip of the appendix was opened and an 8-French infant feeding tube was inserted to ease manipulation of the appendix. The detrusor muscle was incised and opened by electrocautery at the supero-anterior aspect of the urinary bladder. Appendicovesicostomy was performed with 5/0 vicryl in an interrupted manner. The other end of the appendix was retrieved at the right lower quadrant of the abdominal wall. A V flap was created and the stoma was fashioned with 5/0 vicryl. The infant feeding tube was kept in situ as a stent. The whole operation took 555 minutes (9.25 hours).

The patient’s recovery was complicated by urinary tract infection with extended-spectrum beta-lactamase–producing Escherichia coli. Intravenous meropenem 20 mg/kg every 8 hours was initiated for 14 days. The infant feeding catheter was removed and the technique of CIC was taught to the patient’s caregiver.

The continence outcome was good as reported by the patient’s caregiver. There was no urine leak from the stoma or urethra. The technique of CIC with an 8-French catheter 4 times a day was performed uneventfully by the patient’s caregiver until around 6 months after the operation, when examination under anaesthesia and cystogram found mild stenosis of the stoma. Serial dilatation of the stoma site was suggested. There is no urine leak until the bladder reaches 400 mL in capacity. At 3-year follow-up, the patient’s caregiver can catheterise the bladder with ease and the patient has both stomal and urinary continence.

The Mitrofanoff procedure was described in 1980.2 It uses the appendix to create a channel from the urinary bladder to the skin surface. This procedure has helped many patients who cannot tolerate urethral catheterisation over the past three decades. The procedure, however, was done via a conventional open surgery approach until 1993, when Jordan and Winslow3 described the technique of laparoscopic-assisted appendicovesicostomy. Despite the benefit of minimally invasive surgery, this technique has not become popular. In 2004, Pedraza et al4 and Hsu and Shortliffe5 described the use of the robotic-assisted technique in creating an appendicovesicostomy. Since then, a few case reports or case series6 7 8 have described this technique. This is largely attributed to the delicacy of the appendiceal blood supply and challenging intracorporeal anastomosis. The surgical robot offers three-dimensional visualisation, downscaling of surgeons’ tremor and hand movements, range of motion resembling that of the human wrist, and increased degrees of freedom.

The benefits of applying robotic technology for this procedure are greatest at two stages: first when dissecting the appendiceal blood supply and second when recreating a circumferential sealed anastomosis joining the appendix and bladder. Maintaining the blood supply to the appendix is one of the most important steps for avoiding cutaneous stomal stenosis and scarring. The challenge of making an intracorporeal watertight anastomosis may also be an important reason for the scarce reports of the pure laparoscopic approach for this technique. In view of this, there is no doubt that the surgical robot has a fine ability to mimic the open procedure without introducing a large unsightly abdominal incision.

On the other hand, the operative field is limited with the robotic system. This created a problem for this patient, as the appendix and its mesentery was short. The robotic machine was docked towards the feet of the patient and the targeted area of interest was at the pelvis and right lower quadrant. During mobilisation of the upper part of the right colon, crowding of instruments was encountered. As the port was placed as shown in the Figure, the operative field was fixed in the right lower quadrant. For mobilisation of the right colon, the operative field moved from the right lower quadrant to the right upper quadrant. The robotic instruments were not sufficiently flexible for the different surgical fields required for this patient, so we reverted to conventional laparoscopic mobilisation of the right colon. This necessitated more time to redock the whole system back to perform the appendicovesicostomy anastomosis. This is one of the drawbacks of the robotic-assisted Mitrofanoff procedure.

The short-term and mid-term outcomes of this patient are good. She recovered well and became fully mobilised on day 3 after operation. The continence outcome of this patient is good, and the caregiver also found this helpful for doing CIC for this patient.

The robotic-assisted laparoscopic Mitrofanoff procedure is a feasible and safe operation. The technique has the advantage of performing the delicate anastomosis between the appendix and the bladder intracorporeally. Lack of flexibility when changing the surgical field is the major drawback. The robotic-assisted laparoscopic Mitrofanoff procedure can produce a smaller scar and better cosmetic outcome.

1. Meadows M. Computer-assisted surgery: an update. Available from: http://web.archive.org/web/20090301135726/http://www.fda.gov/fdac/features/2005/405_computer.html. Accessed 9 Jul 2015.

2. Mitrofanoff P. Trans-appendicular continent cystostomy in the management of the neurogenic bladder [in French]. Chir Pediatr 1980;21:297-305.

3. Jordan GH, Winslow BH. Laparoscopically assisted continent catheterizable cutaneous appendicovesicostomy. J Endourol 1993;7:517-20. Crossref

4. Pedraza R, Weiser A, Franco I. Laparoscopic appendicovesicostomy (Mitrofanoff procedure) in a child using the da Vinci robotic system. J Urol 2004;171:1652-3. Crossref

5. Hsu TH, Shortliffe LD. Laparoscopic Mitrofanoff appendicovesicostomy. Urology 2004;64:802-4. Crossref

6. Storm DW, Fulmer BR, Sumfest JM. Laparoscopic robot-assisted appendicovesicostomy: an initial experience. J Endourol 2007;21:1015-8. Crossref

7. Thakre AA, Yeung CK, Peters C. Robot-assisted Mitrofanoff and Malone antegrade continence enema reconstruction using divided appendix. J Endourol 2008;22:2393-6. Crossref

8. Willie MA, Zagaja GP, Shalhav AL, Gundeti MS. Continence outcomes in patients undergoing robotic assisted laparoscopic mitrofanoff appendicovesicostomy. J Urol 2011;185:1438-43. Crossref

A 29-year-old woman with a known history of bipolar affective disorder and paranoid schizophrenia admitted to our hospital because of relapse of psychiatric symptoms in June 2011. She had no significant medical illness. Her medication included quetiapine fumarate and sodium valproate but was changed to haloperidol decanoate depot injection, trihexyphenidyl, and clozapine following hospitalisation. Clozapine was commenced at 50 mg once per day and gradually stepped up to 400 mg once per day. One week later she developed fever but had no respiratory or urinary symptoms. She remained conscious and alert with stable vital signs. Physical examination revealed no significant abnormality and preliminary investigations showed normochromic and normocytic anaemia with haemoglobin level of 87 g/L, white cell count of 11.8 x 10⁹ /L (eosinophils 15.1%; absolute count 2.3 x 10⁹ /L), and serum creatinine of 229 µmol/L (baseline serum creatinine 1 week ago, 39 µmol/L). Her liver enzymes, lactate dehydrogenase, and haptoglobin were all within normal range. Chest radiograph showed clear lung fields. She was empirically given amoxicillin/clavulanic acid but treatment was complicated by gastro-intestinal side-effects such as vomiting and diarrhoea. The antibiotics were stopped immediately and the symptoms subsided. Clozapine was further titrated up to 700 mg once per day with consequent improvement in her mental state. Nonetheless, fever persisted with further deterioration in renal function (serum creatinine rose to 356 µmol/L). Autoimmune markers including anti–nuclear antibody, anti–neutrophil cytoplasmic antibodies, and anti–glomerular basement membrane antibody were all within normal range. Urinalysis revealed the presence of red blood cells and eosinophils but urine culture showed no bacterial growth. The 24-hour urine protein was 1.18 g. Ultrasound of the urinary system showed normal-sized kidneys with no hydronephrosis. Ultrasound-guided renal biopsy was performed and the histology showed features of tubulointerstitial nephritis with eosinophil-rich interstitial infiltrates and occasional granulomas (Fig). The likely diagnosis was drug-induced acute interstitial nephritis (AIN). Clozapine was withheld, fever subsided afterwards and renal function gradually returned to normal 4 weeks following cessation of clozapine.

Drug-induced AIN is not uncommon. Common nephrotoxic drugs include non-steroidal anti-inflammatory drugs (NSAIDs) and antibiotics such as aminoglycosides and vancomycin. Although amoxicillin/clavulanic acid remains a possible culprit in this case for AIN, the short duration of amoxicillin/clavulanic acid use and sequence of events are more suggestive of clozapine-induced AIN.

Acute interstitial nephritis is defined as an immune-mediated condition characterised by the presence of inflammation and oedema in the tubulointerstitium of the kidneys. It accounts for 15% to 27% of biopsy-proven acute kidney injury. Acute interstitial nephritis is most commonly drug-induced although the cause may also be infective, autoimmune, or idiopathic.1 2 3 4 5 The classic triad—fever, skin rash, and eosinophilia—is only present in 5% to 10% of patients with AIN.2 3 4 5 As a result, a high level of clinical suspicion is essential since around 40% of patients with AIN eventually required dialysis.2 A detailed drug history, especially herbal medicine which is common in our locality, recreational drugs and radio-contrast, are important for diagnosis. Other history including water exposure and animal contact (pets or stray animals) can help exclude or confirm several infective causes such as Legionnaires’ disease and leptospirosis. Systemic manifestations of vasculitis should also be specifically looked for during physical examination.

There are no specific signs and symptoms to differentiate drug-induced AIN from other causes of AIN. Fever is present in around 30% of patients with drug-induced AIN3 5 and it typically occurs within 2 weeks of initiation of a new drug.3 Skin rash, usually of morbilliform or maculopapular appearance, is found in only 15% to 50% of patients, depending on the type of medication.3 5 One retrospective review showed that around 45% of patients have arthralgia, and 15% and 21% of patients have dysuria and loin pain, respectively.5 Eosinophilia is thought to have great diagnostic value in drug-induced AIN as it signifies a hypersensitivity reaction although the degree and frequency of eosinophilia vary with different medications.4 Methicillin-induced AIN is associated with eosinophilia in 80% of cases while AIN due to NSAID is less commonly associated with eosinophilia, which is only around 35% of cases.4 However, the presence of eosinophilia can also be found in infections, especially those caused by helminths, allergic diseases such as asthma and eczema, and even malignant conditions such as lymphoma and carcinoma of the colon. Like eosinophilia, the presence of eosinophiluria is neither sensitive nor specific for drug-induced AIN. The sensitivity ranges from 63% to 91%, and specificity from 52% to 94%.3 4 Other conditions such as lower urinary tract infection, pyelonephritis, prostatitis, acute tubular necrosis, glomerulonephritis, and urinary schistosomiasis can also result in eosinophiluria.3 Other parameters from urine samples may also provide clues for drug-induced AIN. Proteinuria is present in 93% of patients but only 2.5% have a nephrotic range of proteinuria.2 Haematuria is usually microscopic and is present in 60% to 80% of cases while gross haematuria is only present in 5% of patients.2 Renal biopsy can confirm the diagnosis of AIN by demonstrating inflammation and oedema of the renal interstitium and tubulitis.2 3 4 5 The presence of a considerable number of eosinophils in the interstitium will point to a diagnosis of drug-induced AIN, while an abundance of neutrophils is suggestive of an infective cause.3

As drug-induced AIN is idiosyncratic and not dose-dependent, the mainstay of treatment is cessation of the causative agents. Nonetheless, not all patients experience complete recovery despite withdrawal of the index medication. Neither the severity of renal failure, the extent of interstitial involvement (including fibrosis), nor the severity of tubulitis predicts the clinical outcome.2 3 4 5 More established prognostic factors are the duration of renal failure and creatinine level 6 to 8 weeks after diagnosis.4 Some studies advocate the use of corticosteroid to hasten recovery and prevent progression to chronic kidney disease6 but these studies have usually been small and retrospective.2 3 4

Since 1999, 10 cases of clozapine-induced AIN have been described.6 7 8 Among these patients, the ages ranged from 24 to 69 years, and six were male. In patients who presented within 2 weeks of commencing clozapine, 80% exhibited a hypersensitivity reaction. In those who presented late, symptoms developed up to 3 months after starting clozapine. Fever was present in 80% but, surprisingly, none reported skin rash or arthralgia. Proteinuria was detected in 80% of cases, but only four patients had red blood cells in the urine. Eosinophilia was present in half of the patients only. Four patients had the diagnosis of AIN confirmed by histology. A phenomenon is observed wherein the effect of clozapine on the kidney can be potentiated by the concomitant use of antibiotics, especially those that are known to have higher risks of interstitial damage, such as the penicillin derivatives.6 In our patient, the temporal relationship between the initiation of clozapine and the development of acute kidney injury matched the time frame described in the literature. In addition, the presence of fever, eosinophilia, and eosinophiluria also raised the possibility of clozapine-induced AIN, subsequently confirmed by histology. The renal function of our patient also improved spontaneously after removing the index medication.

In conclusion, this case highlights the rare but important potential side-effect of clozapine. In addition to monitoring cell counts, regular monitoring of renal function is recommended after initiation of clozapine. Early involvement of nephrologists can provide early recognition of this entity with prompt investigation and treatment.

1. Bellomo R, Kellum JA, Ronco C. Acute kidney injury. Lancet 2012;380:756-66. Crossref

2. Praga M, González E. Acute interstitial nephritis. Kidney Int 2010;77:956-61. Crossref

3. Perazella MA, Markowitz GS. Drug-induced acute interstitial nephritis. Nat Rev Nephrol 2010;6:461-70. Crossref

4. Rossert J. Drug-induced acute interstitial nephritis. Kidney Int 2001;60:804-17. Crossref

5. Clarkson MR, Giblin L, O’Connell FP, et al. Acute interstitial nephritis: clinical features and response to corticosteroid therapy. Nephrol Dial Transplant 2004;19:2778-83. Crossref

6. Kanofsky JD, Woesner ME, Harris AZ, Kelleher JP, Gittens K, Jerschow E. A case of acute renal failure in a patient recently treated with clozapine and a review of previously reported cases. Prim Care Companion CNS Disord 2011;13:PCC.10br01091.

7. An NY, Lee J, Noh JS. A case of clozapine induced acute renal failure. Psychiatry Investig 2013;10:92-4. Crossref

8. Mohan T, Chua J, Kartika J, Bastiampillai T, Dhillon R. Clozapine-induced nephritis and monitoring implications. Aust N Z J Psychiatry 2013;47:586-7. Crossref

Optic nerve aplasia is a very rare congenital anomaly that is typically unilateral, and is characterised by congenital absence of the optic nerve, central retinal vessels, and retinal ganglion cells.1 Bilateral cases are exceedingly rare. Various ocular anomalies are associated with it.

A female infant weighing 3225 g was born to a 26-year-old G1P1 female at full term via caesarean section because the umbilical cord was around the neck. She was found to have left microphthalmos on routine postnatal check-up in December 2013 in Hong Kong, at the age of 3 months. Family history was negative for ocular or other birth defects. Her mother was a housewife, with no history of any major illness during the pregnancy and antenatal workup was unremarkable. Physical examination was unremarkable with normal development for her age.

Eye examination of the infant at 4 months revealed left microphthalmos, and a left convergent squint with no definite visual following. The left pupil did not react to light stimulation and a persistent pupillary membrane was evident. Coloboma of the left optic disc was suspected. Fundus examination showed whitish choroidal atrophy with a flat optic disc on the left side. Right eye examination including fundus examination was unremarkable as were all blood tests and urinalysis.

Magnetic resonance imaging performed at 4 months revealed left microphthalmos, with no recognisable left optic nerve. The right optic nerve was present and normal in size. The optic chiasm was seen and slightly deviated towards the right side, likely related to the absence of the left optic nerve (Fig 1). Bilateral optic tracts and optic radiations were symmetrical. The septum pellucidum and corpus callosum were intact and all other cerebral and ocular structures were unremarkable (Fig 2).

Aplasia of the optic nerve is a rare congenital anomaly that is typically unilateral. It occurs sporadically in an otherwise healthy person without sexual or racial predilection,2 or any evidence of an inherited factor.

Prenatal history is usually normal, but the possible influence of external factors such as episodes of viral infection in the first trimester,3 acetone exposure, or smoking during pregnancy4 cannot be excluded.

The pathogenesis of optic nerve aplasia remains unclear although it was first described 140 years ago. Scheie and Adler5 suggested that the defect in aplasia was failure of the mesoderm to enter the fetal fissure and provide vascularisation of the retina and nerve tissue. Weiter et al6 doubted the defective mesodermal development, since the dural sheath (a mesodermal derivative) was present in the majority of their cases. Instead, they suggested that the ventral invagination of the optic vesicle causes nerve fibre misdirection and secondary atrophy. Yanoff et al7 postulated a primary failure of the ganglion cell to develop and send out axons, resulting in a lack of induction of mesodermal ingrowth including a lack of retinal blood vessel development. Hotchkiss and Green8 agreed that failure of mesodermal induction was secondary to third-order neuronal defect in the ganglion cell layer.

Plain X-ray can demonstrate a small optic foramen on the side of aplasia.9 Computed tomographic scan may show the globe and orbit on the affected side to be smaller than the normal side. Magnetic resonance imaging will show the absence of optic nerve on the affected side. The chiasm and lateral geniculate body may also appear small.10

Histopathological findings in optic nerve aplasia include the absence of ganglion cells and their axons as well as the absence of retinal vessels.7

According to many previous statements, aplasia of the optic nerve is a part of hypoplasia of the optic spectrum. According to an analysis performed by Alqahtani,2 of 42 cases in the literature, 29 were genuine aplasia of the optic nerve, while the remainder were hypoplastic optic nerve.

Unilateral aplasia of the optic nerve is often present in malformed eyes, with no abnormality in brain tissue. Possible malformations of the eye include microphthalmos, cataract, retinal dysplasia, coloboma of the iris and ciliary body, iris hypoplasia, malformation of the chamber angle, and persistent hyperplastic primary vitreous.11 No light perception is present in the affected eye and light stimulation elicits no direct or consensual pupillary response. Light stimulation of the normal eye results in a direct or consensual pupillary response.11 Possible malformation of the central nervous system includes hydranencephaly, orbital meningoencephalocele, and anencephaly.5 6

The prognosis of optic nerve aplasia is poor. There is no specific treatment and blindness occurs in the affected eye. Management of such cases is directed towards identifying any associated ophthalmological or neurological problems. Cavallini et al12 recommended ocular prosthesis in patients with associated microphthalmos, to enable normal development of the orbit, at least for aesthetic purposes.

Optic nerve aplasia should be suspected in a patient who presents with unilateral microphthalmos that is associated with the absence of central retinal vessels and ganglion cells. Magnetic resonance imaging is useful to screen for other associated intracranial abnormality.

1. Blanco R, Salvador F, Galan A, Gil-Gibernau JJ. Aplasia of the optic nerve: report of three cases. J Pediatr Ophthalmol Strabismus 1992;29:228-31.

2. Alqahtani J. Optic nerve aplasia: a case report and literature review. J Pediatr Neurosci 2008;3:150-3. Crossref

3. Ginsberg J, Bove KE, Cuesta MG. Aplasia of the optic nerve with aniridia. Ann Ophthalmol 1980;12:433-9.

4. Barry DR. Aplasia of the optic nerves. Int Ophthalmol 1985;7:235-42. Crossref

5. Scheie HG, Adler FH. Aplasia of the optic nerve. Arch Ophthalmol 1941;26:61-70. Crossref

6. Weiter JJ, McLean IW, Zimmerman LE. Aplasia of the optic nerve and disk. Am J Ophthalmol 1977;83:569-76. Crossref

7. Yanoff M, Rorke LB, Allman MI. Bilateral optic system aplasia with relatively normal eyes. Arch Ophthalmol 1978;96:97-101. Crossref

8. Hotchkiss LH, Green WR. Optic nerve aplasia and hypoplasia. J Pediatr Ophthalmol Strabismus 1979;16:225-40.

9. Little LE, Whitmore PV, Wells TW Jr. Aplasia of the optic nerve. J Pediatr Ophthalmol 1976;13:84-8.

10. Margo CE, Hamed LM, Fang E, Dawson WW. Optic nerve aplasia. Arch Ophthalmol 1992;110:1610-3. Crossref

11. Howard MA, Thompson JT, Howard RO. Aplasia of the optic nerve. Trans Am Ophthalmol Soc 1993;91:267-76; discussion 276-81.

12. Cavallini GM, Forlini M, Gramajo AL, et al. Optic nerve aplasia and microphthalmos: a case report. J Genet Syndr Gene Ther 2013;4:175. Crossref