Background and aims Acute necrotizing encephalopathy in childhood (ANEC) is a disease characterised by acute encephalopathy and radiological features of bilateral thalamic necrosis. Medium and long term morbidity is not well described. We describe the mortality and morbidity outcomes in our paediatric cohort with this disease.

Methods This is a retrospective ten-year series. Children aged one month to 18 years diagnosed with ‘ANEC’ were collated from Neurology and Radiology databases.

18 fulfilled clinical criteria of acute encephalopathy. All were scored with Mizuguchi’s radiological checklist by two paediatric neurologists and one radiologist. 11 cases scored unlikely were excluded.

Data analysis focused on discharge and follow-up outcomes.

Results 7 patients were analysed. The median age was 3.7 years. All were previously well with normal development. All had impaired consciousness at presentation with preceding fever and prodrome. Typical radiology showed bilateral thalamic involvement with/without areas of haemorrhage and necrosis. Causative organisms included Influenza A H1N1, Human Herpes Virus 6 and Metapneumovirus. All were treated with steroids, immunoglobulin or both.

Outcomes were evaluated at discharge and follow-up and divided into good or poor (including death). One passed away from brainstem death. All had neurological deficit at discharge: 50% mildly affected; 50% severely affected. 00% in the former group restored normal neurological function on follow-up. In the latter, two responded well to rehabilitation but one remained severely impaired.

Conclusions ANE mortality at our institution is 14%. Morbidity of survivors at discharge is 100%. Long term follow up morbidity however, improves to 50% with half achieving normal neurological function at follow up.