Arnold-Chiari syndrome is a series of nervous system symptoms related to a deformity of the skull.
This condition is often present at birth, but can also develop later in life. Some people with 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 occurs with a myelomeningocele, which is a form of spina bifida or syringomyelia, which is fluid cavites in the spinal cord.
Brain Stem and Lower Brain
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There are no known risk factors for Chiari malformation. There may be a genetic connection in some families.
Symptoms in infants are due to pressure on the lower part of the brain and brainstem. They may include:
Symptoms in adolescents are usually milder and may include:
You will be asked about symptoms and medical history. A physical exam will be done. Imaging tests evaluate the brain and skull. These may include:
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 and the degree of pressure on the brain. For example:
Talk with your doctor about the best treatment plan for you.
American Syringomyelia and 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.uchicagokidshospital.org/online-library/content=P02592. Accessed February 12, 2014.
Chiari malformations. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated March 12, 2012. Accessed February 12, 2014.
Chiari malformation information page. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/chiari/chiari.htm. Updated December 30, 2013. Accessed February 12, 2014.
Hekman KE, Aliaga L, et al. Positive and negative predictors for good outcome after decompressive surgery for Chiari malformation type 1 as scored on the Chicago Chiari Outcome Scale. Nuerol Res. 2012;34(7):694-700.
Last reviewed January 2015 by Rimas Lukas, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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