Prevalence
Very small; 1 case annually in specialized centers.

Age at onset
1 to 10 years; peak at 5 to 6 years.

Sex
Males = females.

Neurological and mental state
Normal.

Etiology
Unknown. Chronic viral infection? Abnormal immune response to viral infection? Autoimmune disorder unrelated to infection?

Clinical manifestations
Three stages:

  • First stage with simple focal motor or somatosensory seizures or with epilepsia partialis continua (60%), complex focal seizures without automatisms or secondarily generalized tonic-clonic seizures (GTCS). Seizures deteriorate in weeks or months. Hemiparesis is initially post-ictal and later permanent.
  • In the second stage (3 months to 10 years from onset), seizures become longer, more frequent, and widespread. Neurological and mental deficits: hemiparesis, hemihypesthesia, hemianopia, intellectual/language impairment.
  • In the third stage, seizure severity and progression of deficits burn out.

Diagnostic procedures
No specific diagnostic procedure or abnormality. At onset, all functional and structural tests may be normal. It is the progression and the localization that may be consistent with this diagnosis.

CSF: non-specific abnormalities in half of patients. Oligoclonal or monoclonal banding may be found.

Serial CT brain scan and preferably MRI: progressive hemiatrophy, usually starting in the temporo-insular region.

Magnetic resonance spectroscopy: decreased relative N-acetylaspartate signal intensity over the affected hemisphere.

Functional brain imaging – single photon emission computed tomography (SPECT) and positron emission tomography (PET): inter-ictal hypoperfusion and hypometabolism in the affected side, which worsens with progression of the disease and may be abnormal at a stage that MRI is normal. Ictally, there is regional hyperperfusion corresponding to the epileptogenic region.

Inter-ictal EEG
Normal initially but gradually deteriorates to severe unilateral abnormalities (slow waves, poverty of physiological rhythms). Inter-ictal multifocal spikes, sharp waves in nearly all EEGs.

Ictal EEG
Multifocal onset. Focal motor seizures may occur without concomitant EEG changes. Conversely, ictal EEG paroxysms may frequently occur without discernible clinical manifestations. Epilepsia partialis continua often lacks clinico-EEG correlations.

Prognosis
Devastating, with intractable seizures and fixed neurological deficits.

Differential diagnosis
Initially focal seizures and later encephalitis.

Management options*
Seizures are refractory to AEDs. Intravenous immunoglobulin, steroids, and plasma exchange give equivocal results.

Functional hemispherectomy.

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

This section 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. The Educational Kit on Epilepsies was produced through an unrestricted educational grant from UCB Pharma SA.

UCB Pharma SA assumes no responsibility of the views expressed and recommended treatments in these volumes.

Authored by: C. P. Panayiotopoulos MD PhD FRCP on 1/2005
Reviewed by: Steven C. Schachter MD on 6/2008
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