Idiopathic childhood occipital epilepsy of Gastaut

C P Panayiotopoulos MD PhD (Dr. Panayiotopoulos of St. Thomas' Hospital has no relevant financial relationships to disclose.)
Jerome Engel Jr MD PhD, editor. (Dr. Engel of the David Geffen School of Medicine at the University of California, Los Angeles, has no relevant financial relationships to disclose.)
Originally released October 18, 1993; last updated July 12, 2016; expires July 12, 2019

This article includes discussion of idiopathic childhood occipital epilepsy of Gastaut, childhood epilepsy with occipital paroxysms, Gastaut type of benign childhood occipital epilepsy, idiopathic childhood occipital epilepsy, idiopathic childhood occipital lobe epilepsy, late onset benign childhood epilepsy with occipital paroxysms, late onset benign childhood occipital epilepsy. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.

Overview

Idiopathic childhood occipital epilepsy of Gastaut is a purely occipital epileptic syndrome that manifests with frequent and brief visual seizures of elementary visual hallucinations, blindness, or both. Postictal headache is common. Interictal EEG shows occipital paroxysms that are activated by the elimination of fixation and central vision (fixation-off sensitivity) or just occipital spikes; rarely, it may be normal. The syndrome is often misdiagnosed as basilar migraine or migraine with visual aura. Conversely, structural (symptomatic) epilepsies may imitate this syndrome. Misdiagnosis with Panayiotopoulos syndrome may occur if symptoms are not properly assessed. Prognosis is usually good, with remission of seizures and normalization of the EEG by the late teenage years. In this update, the author details developments in this idiopathic childhood occipital epilepsy and provides clues for its proper differential diagnosis in relation to migraine, structural occipital epilepsies, and Panayiotopoulos syndrome.

Key points

 

• Idiopathic childhood occipital epilepsy of Gastaut is purely occipital epilepsy with onset usually in late childhood and in the early teenage years.

 

• It manifests mainly with typical visual seizures of elementary visual hallucinations that are usually of brief duration.

 

• Seizures may be very frequent and on a daily basis.

 

• Postictal headache occurs in one third of patients, and it is often indistinguishable from migraine headache.

 

• EEG often shows occipital spikes or occipital paroxysms, which, when they occur, show fixation-off sensitivity. However, some patients have consistently normal EEG.

 

• Misdiagnosis with migraine is a common clinical problem.

 

• Prognosis is good in half of patients.

 

• Treatment with appropriate antiepileptic medication, and mainly with carbamazepine, is often needed.

Historical note and terminology

Gibbs and Gibbs documented that on EEG “. . . seizure foci in one or both occipital lobes are most commonly found in young children. Occipital foci tend to disappear in adult life, and the subsidence of the electroencephalographic abnormality is usually accompanied by a cessation of seizures” (Gibbs and Gibbs 1952). Peak age at first discovery of occipital foci was 4 to 5 years, and they could occur in children without seizures. Gibbs and Gibbs also described an 8.5-year-old boy with “onset of attacks 2 months before the recording, consisting of blindness, followed by holding both hands to eyes, rolling up of eyes, and loss of consciousness. . . severe headache after attack. . . no convulsions at any time” (Gibbs and Gibbs 1952). EEG showed independent bilateral occipital spikes. Although similar cases were later reported by other authors, the recognition of idiopathic childhood occipital epilepsy of Gastaut was delayed. This was motivated by a report by Camfield and colleagues of 4 adolescents with EEG occipital paroxysms on closed eyes whose clinical features were interpreted as basilar migraine causing seizures (Camfield et al 1978). Panayiotopoulos questioned the diagnosis of basilar migraine and reported 4 children with occipital paroxysms activated by elimination of central vision and fixation (fixation-off sensitivity); 2 of them had what is now known as Panayiotopoulos syndrome, 1 had what is now known as idiopathic childhood occipital epilepsy of Gastaut, and 1 had symptomatic occipital epilepsy (Panayiotopoulos 1980; Panayiotopoulos 1981).

Video: Occipital paroxysms activated by elimination of central vision and fixation
Image: Occipital paroxysms with eyes open and closed in a lit room (EEG)
Image: Occipital paroxysms with eyes open and closed in total darkness (EEG)
Image: Occipital paroxysms with fixation on and off with eyes open (EEG)
Subsequently, Gastaut retrospectively identified 36 patients with occipital paroxysms and widely reported them as “a new type of epilepsy: benign partial epilepsy of childhood with occipital spike-waves” (Gastaut 1982; Gastaut and Zifkin 1987). The 1989 International League Against Epilepsy (ILAE) classification recognized this syndrome as “childhood epilepsy with occipital paroxysms” (Commission 1989). This has been renamed as “late-onset childhood occipital epilepsy (Gastaut type)” in the ILAE reports (Engel 2001; Engel 2006; Berg et al 2010; Commission on Classification and Terminology of the International League Against Epilepsy 2014). This was based on reports by Fejerman and colleagues (Fejerman 1996; Caraballo et al 1997), rightly proposing that this “Gastaut type-occipital epilepsy (late onset)” is different from Panayiotopoulos syndrome.

According to the ILAE Commission diagnostic manual of the epilepsies (Commission on Classification and Terminology of the International League Against Epilepsy 2014):

Childhood occipital epilepsy (Gastaut type). Late onset childhood occipital epilepsy (Gastaut type) is a self-limiting childhood epilepsy with onset in later childhood. Seizures are usually easily controlled, and remission of seizures occurs within 2 to 4 years from onset.

 

Note. Self-limiting refers to there being a high likelihood of seizures spontaneously remitting at a predictable age.

Clinical context. This syndrome is characterized by onset of seizures between 15 months and 19 years of age (peak 8 to 9 years of age). Remission occurs in 50% to 60% of patients within 2 to 4 years after onset. A dramatic response to carbamazepine is seen in more than 90% of patients. Both sexes are equally affected. Antecedent and birth history is normal. Head size and neurologic examination are usually normal. Development and cognition is normal, although mild cognitive impairment has been described.

 

Caution. Epileptic encephalopathy with continuous spike-and-wave during sleep can occur as a comorbid disorder. Consider a sleep EEG in cases that develop cognitive deterioration.

Seizures.

Mandatory seizures. Seizures with visual aura occur from awaken states. These have rapid onset and are brief (typically seconds, most less than 3 minutes, rarely up to 20 minutes), and they are frequent without treatment. Typically, elementary visual phenomena occur, which are described as small multi-colored circles that are seen in the peripheral vision, increasing in area of the visual field involved and moving horizontally to the other side. This may be followed by deviation of the eyes or turning of the head (to the side ipsilateral to the hemisphere of seizure onset).

Other occipital features may occur, including ictal blindness, complex visual hallucinations, visual illusions (eg, of occipital movement), orbital pain, eyelid fluttering or repetitive eye-closure, ictal headache, or nausea and vomiting. Postictal headache is common (seen in 50%) and may be associated with nausea and vomiting (10%, especially if seizure networks are in the nondominant hemisphere).

The seizure may spread outside the occipital lobe, resulting in hemiparesthesia, dyscognitive features (14%), a hemiclonic (43%), or bilateral convulsion (13%).

Typical absence seizures may occur in some patients after the onset of occipital seizures.

 

Caution. If seizures with dyscognitive features are frequent or complex visual hallucinations occur with affective aura, consider structural brain abnormality.

Background EEG. The background EEG is normal.

Interictal. Occipital spike or spike-and-wave is seen in the interictal EEG of the majority of patients with this syndrome but may only occur in the sleep EEG. Centrotemporal, frontal, or generalized spike-and-wave may coexist (seen in 20% of cases).

 

Caution. Epileptic encephalopathy with continuous spike-and-wave during sleep can occur as a comorbid disorder. Consider a sleep EEG in cases that develop cognitive deterioration.

Activation. Fixation-off sensitivity (facilitation of epileptiform discharges with elimination of central vision) is seen in 20% to 90% of patients. Giant somatosensory spikes may occur. EEG abnormality is enhanced by sleep deprivation and by sleep. It is debated whether a response to intermittent photic stimulation can be seen in this syndrome or is exclusionary.

Ictal. At ictal onset, there is a reduction in the usual background occipital spike or spike-and-wave with the sudden appearance of occipital faster rhythms with spikes of low amplitude. There may be slower spike-and-wave during oculo-clonic seizures or ictal blindness.

Imaging. Neuroimaging is normal. High resolution MRI is required to exclude structural brain abnormality.

Genetics.

 

Pattern of inheritance

Unknown, there may be hereditary and environmental factors involved.

 

Known genes

There are no known genes.

 

Family history of seizures/epilepsy

A family history of febrile seizures or epilepsy is common (seen in up to a third of cases), and a family history of migraine is also reported (9% to 16% of cases).

 

Differential diagnosis

• Focal seizures due to structural brain abnormality
• Celiac disease, epilepsy, and cerebral calcification syndrome (check anti-gliadin antibodies)

Migraine with visual aura. For extensive reviews of idiopathic childhood occipital epilepsy of Gastaut, see the following references (Panayiotopoulos 1999b; Panayiotopoulos 2002; Panayiotopoulos 2010; Fejerman and Caraballo 2007; Caraballo et al 2008; Caraballo et al 2009; Gobbi et al 2008; Panayiotopoulos et al 2008; Panayiotopoulos et al 2012; Vigevano et al 2013).

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