hemimegalencephaly
Pronunciation: HEM-ee-meg-ah-lo-en-SEF-ah-lee
A rare malformation characterized by unilateral overgrowth of one cerebral hemisphere, often associated with intractable seizures and developmental delays.
Full Definition
Hemimegalencephaly is a congenital brain malformation involving abnormal overgrowth and dysplasia of one cerebral hemisphere. The affected hemisphere is enlarged with thickened cortex, abnormal gyral patterns, and often contains dysplastic tissue. This condition typically presents in infancy with severe, medically refractory seizures, developmental delays, and progressive neurological deterioration. The seizures often originate from the affected hemisphere and may require surgical intervention, including hemispherectomy, for seizure control.
Usage
Usage note: Often abbreviated as HME in clinical notes; associated with severe epilepsy requiring surgical management.
In Context
- "The infant's intractable seizures were secondary to left hemimegalencephaly identified on MRI." — Epilepsy surgery evaluation
- "Hemispherectomy was considered for seizure control in this case of hemimegalencephaly." — Neurosurgical consultation