DefinitionBy Mayo Clinic staff
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|Chiari malformation type I|
Chiari malformation (kee-AHR-ee mal-for-MAY-shun) is a condition in which brain tissue protrudes into your spinal canal. It occurs when part of your skull is abnormally small or misshapen, pressing on your brain and forcing it downward. Chiari malformation is uncommon, but improved imaging tests have led to more frequent diagnoses.
The adult form, called Chiari malformation type I, develops as the skull and brain are growing. As a result, signs and symptoms may not occur until late childhood or adulthood. The most common pediatric form, called Chiari malformation type II, is present at birth (congenital).
Treatment of Chiari malformation depends on the form, severity and associated symptoms. Regular monitoring, medications and surgery are treatment options. In some cases, no treatment is needed.
- NINDS Chiari malformation information page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/chiari/chiari.htm. Accessed Sept. 23, 2010.
- Chiari malformation. American Association of Neurological Surgeons. http://www.aans.org/Patient%20Information/Conditions%20and%20Treatments/Chiari%20Malformation.aspx. Accessed Sept. 24, 2010.
- Syringomyelia. American Syringomyelia and Chiari Alliance Project. http://www.asap.org/index.php/disorders/syringomyelia/. Accessed Sept. 24, 2010.
- Developmental diseases of the nervous system. In: Ropper AH, et al. Adams and Victor's Principles of Neurology. 9th ed. New York, N.Y.: The McGraw-Hill Companies; 2009. http://www.accessmedicine.com/content.aspx?aID=3637082. Accessed Sept. 24, 2010.