Early infantile epileptic encephalopathy (EIEE) occurs in early infantile life, typically within the first three months and in many cases in the first two weeks after birth.
The characteristic clinical features include generalized or lateralized tonic spasms, which may occur hundreds of times a day, lasting up to ten seconds each. Other types of convulsions may also occur, such as focal motor seizures, hemiconvulsions or generalized tonic-clonic seizures.
These patients often die in the first year of life. Those who survive show mental and motor disability. The prognosis is dismal however the seizures are managed.
The diagnosis of Ohtahara syndrome is made on the basis of the clinical findings and the suppression-burst pattern on electroencephalography. A neuroimaging modality is advised to screen for structural abnormalities which are sometimes present in these patients. Metabolic conditions must also be screened for.
Early Life Epileptic Encephalopathies: A Personal and Scientific Persepctive
EIEE is an incurable condition at present, and the affected infants must be constantly supervised. Seizures are difficult to control. Some of the drugs used to treat them include benzodiazepines, sodium valproate, levetiracetam, phenobarbital, and zonisamide. None have been significantly successful.
A ketogenic diet which limits carbohydrates is sometimes of use in controlling seizures in this condition, as in some other intractable seizure disorders. This diet is high in fat and supplies adequate protein but very restricted carbohydrate intake.
Associated metabolic abnormalities must be corrected to limit the contribution of these disorders to the symptoms. Among these, supplementation with pyridoxine and biotin are known to be useful in Ohtahara syndrome if pyridoxine deficiency or biotinidase deficiency are detected. Pyridoxine (or vitamin B6) is a cofactor in many vital enzyme reactions involving the metabolism of amino acids, and of homocysteine in particular, as well as of carbohydrates, and lipids. It is also crucial for the synthesis of some neurotransmitters, proper immune function, and the synthesis of hemoglobin.
Biotinidase deficiency is an autosomal recessive condition associated with the inability to break down proteins, either ingested or from cells which are being broken down for recycling because of partial or complete lack of an enzyme needed to degrade biotin. Profound deficiency of the biotinidase enzyme results in seizures, hypotonic muscles, respiratory problems, loss of vision and hearing, ataxia of movement and balance, alopecia, and candidiasis. Treatment with biotin supplements must be continued lifelong in order to prevent or improve these features.
Some structural brain anomalies may also be amenable to surgical correction to improve the clinical features. These include hemimegalencephaly and cortical dysplasia, which are corrected by focal resection or hemispherectomy respectively.
The use of ACTH (adrenocorticotropic hormone) is also useful in a small number of patients, especially to delay the progression to West syndrome which occurs by about 2-6 months in many infants.