(Arnold-Chiari Malformation; Type II Chiari Malformation; Cerebellomedullary Malformation Syndrome)
Arnold-Chiari syndrome is a series of nervous system symptoms.
This condition is often present at birth, but can also develop later in life. Some people with very mild forms of this syndrome may never know they have the condition. For others it can be more severe. These severe forms will need treatment.
Arnold-Chiari syndrome is caused by a problem in the back of the skull. The skull should have an indented space in the back of the head. The rear lower part of the brain and the brainstem are in this space. In some people, this indented skull space does not develop well. This is called Chiari malformation. The space inside the skull is too small for the brain. As a result, the brain and brain stem are pushed downward. It blocks the flow of fluid from the brain to the spinal column.
The problem with the skull develops before birth. It is not clear why it happens. In some cases, it is accompanied by a myelomeningocele, which is a form of spina bifida.
There are no known risk factors for Chiari malformation. There may be a genetic connection in some families.
Symptoms in infants may include:
Symptoms in adolescents are usually milder and may include:
Your doctor will ask about your symptoms and medical history. A physical exam will be done. Your doctor may also need detailed images of the brain and skull. The pictures may be taken with:
Special studies may also be done to evaluate the flow of fluid around your brain and spinal cord.
Treatment will be based on individual symptoms. For example:
The malformation may also block the flow of fluid in the brain and spine. Surgery may be needed to correct the flow of fluid. Surgery may also be done to release compression of the brain.
Talk with your doctor about the best treatment plan for you.
There is no known way to prevent Arnold-Chiari syndrome. Genetic counseling may help parents of a child with this condition to determine the risk in future children.
American Syringomyelia & Chiari Alliance Project
National Institute of Neurological Disorders and Stroke
Canadian Neurological Sciences Federation
Chiari malformation. Comer Children’s Hospital website. Available at: http://www.uchicag... . Accessed May 21, 2013.
Chiari malformations. EBSCO DynaMed website. Available at: http://dynamed102.ebscohost.com/Detail.aspx?id=115525 . Updated March 12, 2012. Accessed May 21, 2013.
Chiari malformation information page. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/chiari/chiari.htm . Updated April 18, 2013. Accessed May 21, 2013.
Last reviewed May 2013 by Rimas Lukas, MD; Michael Woods, MD