Prevalence
~5% to 10% of epilepsies, both in neurosurgical series and demographic studies.

Age at onset
Any age. Idiopathic occipital epilepsy appears in late childhood.

Sex
Males = females.

Neurological and mental state
Normal or abnormal depending on etiology.

Etiology
Symptomatic, cryptogenic, idiopathic, or metabolic. Symptomatic causes are congenital, residual, or progressive (malformations of cortical development, vascular, neoplastic, metabolic, hereditary, congenital, inflammatory, parasitic infections). Metabolic or other derangement such as eclampsia may have a particular predilection for the occipital lobes. There is an association between coeliac disease and occipital lobe epilepsy. Occipital seizures may be the first manifestation of Lafora disease or mitochondrial disorders.

Clinical manifestations
The cardinal symptoms are mainly visual and oculomotor. Visual symptoms are (1) elementary and less often complex visual hallucinations; (2) blindness; (3) visual illusions; and (4) palinopsia. Ictal oculomotor symptoms are (1) tonic deviation of the eyes (pursuit-like than oculotonic); (2) oculoclonic or nystagmus; and (3) repetitive eyelid closure or eyelid fluttering.

Elementary visual hallucinations mainly consist of multicolored circular patterns that develop fast in sec and they are usually brief for several sec to rarely 1 to 3 min.

Seizures may spread to anterior regions, generating symptoms from the temporal, parietal, and frontal lobes and secondarily hemiconvulsions or generalized convulsions.

Typically post-ictal headache often indistinguishable from migraine occurs in 1/3 to 1/2 of patients.

Frequent, sometimes many per day, and often in multiple clusters.

Timing
Predominantly diurnal.

Diagnostic procedures
MRI for all patients. Hematology, biochemistry, screening for metabolic disorders, molecular DNA analysis, or even skin or other tissue biopsy may be needed for cases of undetermined cause.

Inter-ictal EEG
Background of symptomatic cases is usually abnormal, with posterior lateralized slow waves, asymmetrical alpha and photic following, and often unilateral occipital spikes.

Background of idiopathic cases is normal, often with occipital spikes or occipital paroxysms.

Ictal EEG
Occipital paroxysmal fast activity, fast spiking, or both; brief occipital flattening may occur prior to this.

1/3 of occipital seizures do not show appreciable changes.

Prognosis
Frequency, severity, and response to treatment vary considerably from good to intractable or may be progressive, depending mainly on the underlying cause.

Differential diagnosis
Migraine, normal phenomena, and psychogenic or other causes unrelated to seizures. Migraine visual aura is fundamentally different from visual seizures.

Management options*
AEDs indicated for focal seizures. Carbamazepine, levetiracetam and lamotrigine are the drugs of first choice. Neurosurgery for severe symptomatic cases may be selectively effective.

*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

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