Chiari Malformation

Chiari malformation (also called Arnold-Chiari malformation) is a rare congenital anomaly in which two parts of the brain, the brainstem and the cerebellum, are longer than normal and protrude down into the spinal canal.

Chiari malformation may be associated with many other anomalies including myelomeningocele, syringomyelia, and spina bifida. Hydrocephalus (increased intracranial pressure) may also occur.

In most cases, symptoms begin during infancy, however onset of symptoms may be delayed until adolescence or adulthood. Symptoms usually include vomiting, muscle weakness in the head and face, difficulty swallowing, and varying degrees of mental impairment. Paralysis of the arms and legs may also occur.

Adults and adolescents with Chiari malformation who previously were asymptomatic may show signs of progressive brain impairment as they grow older, such as involuntary, rapid, downward eye movements. Other symptoms include dizziness, headache, double vision, deafness, an impaired ability to coordinate movement, and episodes of acute pain in and around the eyes.

Children with Chiari malformation may require surgery to repair an existing myelomeningocele. Hydrocephalus may be treated with surgical implantation of a shunt to relieve increased pressure on the brain. Some adults with Chiari malformation may benefit from surgery to enlarge the opening in the back of the skull to relieve intracranial pressure.

Most patients who have surgery experience an improvement of their symptoms. Some patients may experience prolonged periods of relative stability. Infants with very severe malformations may have life-threatening complications.

Information provided by the
National Institute of Neurological Disorders and Stroke,
National Institutes of Health

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.