Clinical Aspects of Hemimegalencephaly by Means of a Nationwide Survey

Abstract

We surveyed Japanese patients with hemimegalencephaly by means of a questionnaire. Clinical findings, including intellectual and motor function levels and epileptic symptoms, were investigated. All 44 patients (28 males and 16 females) with hemimegalencephaly were sporadic. Sixteen patients had underlying neurocutaneous syndromes. The number of patients with right-sided hemimegalencephaly ( n = 29) was almost twice that of patients with left-sided hemimegalencephaly ( n = 15). Forty-one patients had mental retardation and hemiparesis and 14 patients were bedridden. All patients had epileptic seizures, which first appeared within a month in 18 cases and within 6 months in 11 cases. In 42 patients, magnetic resonance imaging revealed both cortical and white-matter abnormalities in the affected hemisphere. Antiepileptic drugs were not very effective. Fifteen patients were surgically treated. Eleven patients underwent functional hemispherectomy, which resulted in fairly good seizure control and improved development. There is a correlation between the onset of epilepsy and the degree of clinical severity of motor deficit and intellectual level. Neither underlying disorders nor laterality of the affected side was related to the degree of clinical severity. ( J Child Neurol 2005;20:337—341).

Epilepsy Related to Developmental Tumors and Malformations of Cortical Development

“…Clinically, HME is associated with developmental delay and severe epilepsy with onset typically within the first few months of life [227][228][229][230][231]. Epilepsy is often resistant to pharmacological treatment, requiring surgical intervention to remove or functionally disconnect the epileptogenic area within the affected hemisphere [232].…”

“…Epilepsy is often resistant to pharmacological treatment, requiring surgical intervention to remove or functionally disconnect the epileptogenic area within the affected hemisphere [232]. HME can occur as an isolated malformation or associated with several syndromes [230,231,233,234]. A large spectrum of central nervous system structural abnormalities have been reported, including cases variously defined as "hemimegalencephaly", "focal megalencephaly" "lobar dysplasia", or "localized megalencephaly", in which the abnormalities are detected only over a partial area of one hemisphere [235][236][237].…”

Hemimegalencephaly: Prenatal Diagnosis and Outcome

“…The major clinical features in affected children are mental retardation, developmental delay, psychomotor deficits, progressive hemiparesis, and intractable epilepsy [2,7] . Marked hyperexcitability of the dysplastic cortex usually results in a catastrophic epileptic syndrome in patients with this entity.…”

“…In rare cases, there is hypertrophy of the ipsilateral brain stem and cerebellum [4,5] . There are an isolated form and a syndromic form, in which cutaneous disorders may be observed [6,7] .…”

Neurological manifestations of Proteus syndrome – review of the literature

“…Causative factors were angiolipomatous hamartomas, significant scoliosis, spinal stenosis due to bony abnormalities, tethered cord and multiple meningiomas [24][25][26][27][28]. It was observed in a few cases that even substantial spinal cord lymphangiolipoma infiltration and adipose tissue invasion of the vertebral column had not resulted in any neurological deficit [29,30].…”