Introduction: Hemiconvulsion-Hemiplegia (HH) has been described in patients following prolonged focal, often febrile convulsions and has heterogeneous aetiologies, ranging from structural brain disorders across to immune-mediated causes.^1,2 Here we describe a child with no apparent convulsion prior to the onset of a dense hemiplegia with imaging changes characteristic of HHE, whose condition improved dramatically following immunotherapy.  

Case history: A 7 year old boy with a recent febrile prodrome, presented with a dense right hemiplegia and progressive encephalopathy after a lucid 24 hour interval following a short spontaneously recovering event. He has a well controlled seizure disorder (diagnosed age 2) and his treatment had recently been stopped after 3 years of seizure freedom. His repeat neuroimaging 24 hours later following right sided focal seizures revealed left hemispheric oedema and left parieto-occipital restricted diffusivity. His electroencephalogram showed only attenuated left hemispheric cerebral rhythms. HH syndrome was considered despite the lack of hemiconvulsion due to the striking radiological features. Intravenous corticosteroids and immunoglobulins was commenced as an immune aetiology has been proposed.² He made a full motor recovery after 2 weeks and remains seizure free at 3 months follow-up, although gliotic changes in the temporal and occipital region are revealed on follow-up imaging. Metabolic, immune and genetic (CACNA1A) investigations undertaken have not revealed an aetiology to date.

Conclusion: HHE should be considered even in the absence of hemiconvulsion and the inflammatory response either primary or secondary may respond to early treatment.