Prevalence
Negligible today because of improved emergency care for status epilepticus. 0.06% in the American Collaborative Perinatal Project.

Age at onset
5 months to 4 years; peak at 6 months to 2 years.

Sex
Males = females.

Neurological and mental state
Usually normal prior to the onset of insult.

Etiology
Central nervous system (CNS) infection such as herpes encephalitis. A few may be traumatic or vascular. Frequently no cause is found. High family incidence of febrile seizures.

Clinical manifestations
Sudden unilateral clonic convulsions that last for hours or days if not appropriately treated. Consciousness may be intact. Post-convulsive flaccid hemiplegia follows in all cases; it lasts for more than 7 days and is permanent in more than 80%. The face is always involved and aphasia is present if the dominant side is affected. These signs distinguish acquired post-convulsive from congenital hemiplegia.

Diagnostic procedures
Should include CSF examination. Brain imaging, if possible, should precede lumbar puncture. In the acute stage, there is usually edema in the affected hemisphere. Later, a rather characteristic, uniform hemiatrophy appears. SPECT shows hyperperfusion in the acute stage followed later by hypoperfusion.

Inter-ictal EEG
EEG is not important at the acute stage, although grossly abnormal in the affected hemisphere.

Ictal EEG
Focal discharges of slow waves and spikes. There is no consistent relation between clonic convulsions and EEG discharges.

Prognosis
Depends on cause and speed of effective acute management. Focal seizures appear within 1 to 5 years in 80% of the patients. Secondarily generalized tonic-clonic seizures and often convulsive status epilepticus are common. Learning difficulties are probably the rule. Seizures are usually intractable to anti-epileptic medication.

Management options*
Immediate seizure control (treating status epilepticus with benzodiazepines) and treatment of the underlying illness are essential. Drug treatment is needed for focal epilepsy.

Hemispherectomy is beneficial.

*Expert opinion, please check FDA-approved indications and prescribing information

This page was adapted from:

The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos

Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007

Reviewed and revised June 2008 by Steven C. Schachter, MD