A child recovering from carbamazepine-induced SJS-TEN overlap — long case

Candidate instructions (10-minute long-case discussion)

You are the paediatric registrar on the ward. A 9-year-old girl was admitted three weeks ago with Stevens-Johnson syndrome-toxic epidermal necrolysis overlap, six weeks after starting carbamazepine for new-onset focal epilepsy. She presented with fever, painful red eyes, crusted bleeding lips, dusky target lesions and sheet-like detachment of about 12 percent of body surface area. She is now recovering — her skin is re-epithelialising and her oral intake is improving, but she still has ocular discomfort and photophobia. The examiner asks you to discuss her acute management, the severity assessment, the long-term sequelae and follow-up, and the family pharmacogenetic and drug-avoidance plan. [1]

Your tasks are: [1]

1. Outline the immediate acute management she should have received, including the single most important action. [10]
2. Explain the SCORTEN severity assessment and how it informed her disposition. [1]
3. Discuss the long-term sequelae she is at risk of and the follow-up she needs. [7]
4. Outline her lifelong drug-avoidance plan and the family HLA pharmacogenetic screening. [4]

You are not expected to manage her ongoing ophthalmology care independently — the ophthalmology team is involved, but you should explain its importance. [10]

Examiner discussion points

On the acute management. The examiner will expect the candidate to state that the single most important intervention was to stop the carbamazepine immediately and withdraw non-essential medicines, because earlier withdrawal improves survival. The supportive bundle should be named: cautious fluids at about two-thirds of a thermal-burn formula, early enteral nutrition, non-adherent wound care, analgesia, thromboprophylaxis, and targeted antibiotics only for proven infection. The candidate should explicitly state that IVIG, cyclosporine and corticosteroids have no proven survival benefit, that prophylactic antibiotics are not given, and that the skin is not debrided because it re-epithelialises. [9] [10]

On the severity assessment. The candidate should calculate a SCORTEN from the variables — age, malignancy, heart rate, detachment, urea, bicarbonate and glucose — and explain that a high score with detachment over 10 percent mandated admission to a burn unit or PICU. The mortality bands (about 3 percent at 0 to 1 up to 90 percent at 5 or more) and the day-one and day-three timing should be stated. [1]

On the long-term sequelae. The examiner will probe the ocular sequelae — dry eye, symblepharon, corneal scarring and visual loss — as the commonest and most disabling complication, and the need for ophthalmology follow-up for months regardless of apparent recovery, because late complications develop silently. Skin pigmentation change, nail dystrophy and mucosal strictures are also described, and the psychological burden of a near-fatal drug reaction and prolonged admission should be acknowledged. The candidate should arrange structured follow-up across dermatology, ophthalmology and psychology. [7] [10]

On the drug-avoidance and pharmacogenetic plan. The candidate should state that she must never receive carbamazepine again and should avoid cross-reactive aromatic anticonvulsants — phenytoin, lamotrigine and oxcarbazepine — with levetiracetam or valproate chosen for her ongoing seizure control. MedicAlert identification should be arranged, the culprit and the reaction documented in the chart and the patient record, and HLA-B15:02 screening offered to at-risk relatives (particularly those of Han Chinese, Thai, Malay, Filipino or Indonesian ancestry) before any aromatic anticonvulsant is prescribed. The family should understand that this is a lifelong prescribing-safety conversation, and that the relative risk for HLA-B15:02 carriers being given carbamazepine is what the screening prevents. [4] [3]

Model answer summary

The fellowship answer recognises that this child has survived a severe drug-induced mucocutaneous emergency whose acute management hinged on three things: stopping the culprit drug at once, grading severity with SCORTEN and admitting to a burn-capable setting, and protecting the eye from the first hours. The long-term plan protects her sight with prolonged ophthalmology follow-up, controls her seizures with a non-cross-reactive agent, and prevents recurrence in her relatives through HLA pharmacogenetic screening — because Stevens-Johnson syndrome and toxic epidermal necrolysis are not single episodes but lifelong prescribing-safety events for the child and the family. [4] [10]