engleski

Hemimegalencephaly and Epilepsy.

Introduction: Hemimegalencephaly (HME) is a rare congenital disorder of cortical formation with hamartomatous overgrowth of all or a part of a cerebral hemisphere. HME is divided into three forms: isolated, syndromic (associated with a variety of syndromes typically including hemihypertrophy of the ipsilateral part of the body) and total HME (hemihypertrophy also involves the brain stem and cerebellum). The consequences of asymmetric brain development are contralateral hemiparesis, developmental delay and intractable epilepsy. Recent studies have demonstrated the association of HME with the mutations of AKT3, PK3CA and mTOR genes. mTOR pathway activation causes excitability of neurons, which explains the occurrence of epilepsy in patients with HME. Methods: This small case-series includes six children with different types of HME and epilepsy treated in the Children’s Hospital Zagreb. Results: Out of the six children (3 male and 3 female), three had isolated HME, with the onset of convulsions in the first days of life. In 2/3 (with tonic seizures and a “burst-supression” pattern in EEG) there was Ohtahara syndrome and the third child (with persistent myoclonic and tonic seizures) had extreme megalencephalia with hypertrophy of right hemisphere and accelerated head growth dynamics of 1 cm per week. Two children had syndromic HME (Klippel- Trénaunay-Weber and Epidermal nevus syndrome) and one child (with myoclonic seizures) had total HME, with hemihypertrophy of cerebellum and brain stem. All our patients had refractory epilepsy, psychomotor retardation, and contralateral hemiparesis. Conclusion: In patients with HME treatment is targeted to the control of epilepsy, which can be difficult to manage medically. In refractory cases, hemispherectomy or new therapy with mTOR inhibitors should be considered.

hemimegalencephaly ; epilepsy

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