Ohtahara Syndrome. Early infantile epileptic encephalopathy with bursts-suppression pattern.
Incidence
The prevalence and incidence are unknown.
Clinical Characteristics
Ohtahara syndrome is a rare form of severe epileptic encephalopathy. It manifests with tonic spasms and suppression burst EEG patterns which occur during wakefulness and sleep. Onset may occur before birth in utero or up to 3 months of age. It tends to occur during the first 10 days of life. Tonic spasms which may be either generalized and symmetrical or lateralized can last up to 10 seconds and may occur in clusters. The child may also have focal motor seizures or hemiconvulsions. Rarely the child may have a generalized tonic clonic seizure. Myoclonic seizures are rare. It is considered an epileptic syndrome. The most common etiology is a brain malformation. Some cases have been secondary to Aicardi syndrome and other disorders. Rarely, metabolic disorders have also been cited as causes. Half of the patients die in infancy or childhood. The patients who survive develop severe mental and neurological deficits. Seizures are intractable. Psychomotor development deteriorates rapidly. The patients may become inactive with spastic diplegia, hemiplegia, tetraplegia, ataxia or dystonia. Often there is evolution to West syndrome at age 4–6 months and later into Lennox-Gastaut. The EEG may show the gradual disappearance of the suppression–burst pattern and the emergence of hypsarrhythmia within 3–6 months from onset. It may later progress to show the slow spike-wave EEG patterns of Lennox–Gastaut syndrome if the child reaches the age of 2-3 years. Phenobarbital may reduce the number of seizures. However, the seizures are usually intractable and usually do not respond to antiepileptic medications. Adrenocorticotropic hormone therapy has not shown any benefit. An excellent response to zonisamide was reported in a single case. A short-lived beneficial effect of vigabatrin (Sabril) has been reported. There is a case reported of a good response to vitamin B6. Newer drugs have not been tested. Neurosurgery in focal cerebral dysplasia is sometimes beneficial.
Precipitants
Sleep deprivation can provoke a seizure.
Provocation Tests
EEG is mandatory to make the diagnosis.
Diagnostic Procedures
It is a clinical - EEG diagnosis. EEG is necessary to make the diagnosis. If imaging studies are negative, metabolic screening is mandatory. Some metabolic disorders, such as glutaric aciduria and mitochondrial disorders and others, can also produce cerebral malformations.