encephalocele

Encephalocele is a neural tube defect in which a portion of the brain and meninges herniates through a defect in the skull. If only the meninges protrude, the lesion is typically called a meningocele; when brain tissue is involved, it is an encephalocele.

The defect most often occurs in the occipital region, but frontal, parietal, or basal skull defects also occur. It results from incomplete neural tube closure during early embryogenesis, usually by the fourth week of gestation.

Clinical features and associated anomalies: At birth a sac protrudes through the scalp; size and contents vary. Many cases are associated with hydrocephalus, microcephaly, or other neural tube defects. Prenatal ultrasound can raise suspicion; fetal MRI can help assess brain involvement.

Diagnosis: Prenatal ultrasound may reveal a skull defect with a head sac; MRI provides detail on brain tissue and ventricle status. Postnatally, CT or MRI defines anatomy for surgical planning.

Management and prognosis: Treatment is multidisciplinary. Neonatal or early infancy surgical repair aims to close the skull defect and remove the sac, with tissue repositioning. Outcome depends on brain tissue involvement and associated anomalies; isolated meningoceles have better prognosis than encephaloceles with brain tissue and hydrocephalus.

Prevention and notes: Folate supplementation reduces risk of neural tube defects generally. Avoidance of known teratogens during pregnancy and management of maternal diabetes may lower risk.