HEMICONVULSION-HEMIPLEGIA-EPILEPSY SYNDROME (HHE)

OVERVIEW

Hemiconvulsion-hemiplegia-epilepsy syndrome (HHE) is a rare epilepsy syndrome. It is characterised by an acute febrile focal motor (clonic) status epilepticus followed immediately by hemiplegia in an infant or young child. Acute imaging shows abnormality in one hemisphere of the brain - initially edema that later evolves to atrophy. Later, the child develops chronic drug-resistant focal seizures.

Clinical context

This syndrome typically begins before 4 years of age, affecting males and females equally. Antecedent and birth history is normal. Prior development and neurological examination are normal. There is an acute phase with a prolonged focal status epilepticus that is followed immediately by hemiparesis. The majority of children are left with a permanent motor deficit. However, this deficit may be minimal or resolve in 20%. Aphasia may also be present acutely in up to one quarter of cases if the dominant hemisphere is involved. Later in the chronic phase, focal seizures emerge and are typically drug-resistant, but may be treated with surgery (e.g. hemispherotomy). Many children are also left with variable degrees of intellectual impairment.