MRI with contrast demonstrates leptomeningeal angioma and white matter abnormalities thought to be due to chronic hypoxia and atrophy. Angiomas produce venous engorgement and, presumably, stasis within the involved areas, which are thought to result in hypoxia. Patients present with seizures, hemiparesis, stroke-like episodes, headaches, mental retardation, and learning disabilities. Seizures are the most common associated neurologic abnormality, occurring in 75% of patients, and develop because of ischemic injury to the brain. Many children with Sturge-Weber syndrome are intellectually normal, and seizures are well controlled with standard anticonvulsants. However, progressive ischemia of the underlying brain develops in some children with Sturge-Weber syndrome, resulting in hemiparesis, hemianopia, intractable focal seizures, and cognitive impairment. Hemispherectomy has been proposed for individuals with unilateral disease whose seizures are difficult to control. Intellectual and motor outcome seems improved, compared with ongoing anticonvulsant drug treatment, but the surgical risks and sequelae of the procedure are considerable. Pulse dye laser surgery is the most promising therapeutic option for cosmetic management of the facial nevus flammeus. Expert ophthalmologic management of glaucoma is required. Endocrinology evaluations are also necessary, as these patients often have growth hormone deficiency and/or hypothyroidism.
Central nervous system malformations include disorders of spinal cord and neural tube formation, structure specification (neuronal migration, gray matter), brain growth and size, and skull growth and shape.
The precursor of the nervous system is the neural plate of the embryonic ectoderm, which develops at 18 days of gestation. The neural plate gives rise to the neural tube, which forms the brain and spinal cord, and neural crest cells, which form the peripheral nervous system, meninges, melanocytes, and adrenal medulla. The neural tube begins to form on day 22 of gestation. The rostral end forms the brain, and the caudal region forms the spinal cord. The lumen of the neural tube forms the ventricles of the brain and the central canal of the spinal cord. Most brain malformations are produced by a variety of injuries occurring during a vulnerable period of gestation. Precipitating factors include chromosomal, genetic, and metabolic abnormalities; infections (toxoplasmosis, rubella, cytomegalovirus, herpes); and exposure to irradiation, certain drugs, and maternal illness during pregnancy.