Updated September 10, 2014.

Table of Contents
What is Chiari Malformation?
Is there any treatment?
What is the prognosis?
What research is being done?
Organizations

What is Chiari Malformation?
Arnold-Chiari Malformation is a condition in which the cerebellum portion of the brain protrudes into the spinal canal. It may or may not be apparent at birth. Arnold-Chiari I type malformation usually causes symptoms in young adults and is often associated with syringomyelia, in which a tubular cavity develops within the spinal cord.

Arnold-Chiari II type malformation is associated with myelomeningocele (a defect of the spine) and hydrocephalus (increased cerebrospinal fluid and pressure within the brain), which usually are apparent at birth. Myelomeningocele usually causes paralysis of the legs and, less commonly, the arms. If left untreated, hydrocephalus can cause mental impairment. Either type of Arnold-Chiari Malformation can cause symptoms of headache, vomiting, difficulty swallowing, and hoarseness.

Adults and adolescents who are unaware they have Arnold-Chiari I type malformation may develop headache that is predominantly located in the back of the head and is increased by coughing or straining. Symptoms of progressive brain impairment may include dizziness, an impaired ability to coordinate movement, double vision, and involuntary, rapid, downward eye movements.

Is there any treatment?
Infants and children with myelomeningocele may require surgery to repair protrusion of the meningeal sac into the spinal cord.

Hydrocephalus may be treated with surgical implantation of a shunt to relieve increased pressure on the brain. Some adults with Arnold-Chiari Malformation may benefit from surgery in which the existing opening in the back of the skull is enlarged.

What is the prognosis?
Infants with very severe malformations may have life-threatening complications. Most patients who have surgery experience a reduction in their symptoms. Some patients may experience prolonged periods of relative stability.

What research is being done?
Research supported by the NINDS includes studies to understand how the brain and nervous system normally develop and function and how they are affected by disease and trauma. These studies contribute to a greater understanding of congenital birth defects, such as Arnold-Chiari Malformation, and open promising new doors to potential treatments.

Organizations

American Syringomyelia Alliance Project (ASAP)
P.O. Box 1586
Longview, TX   75606-1586
info@asap.org
http://www.asap.org/
Tel: 903-236-7079 800-ASAP-282 (272-7282)
Fax: 903-757-7456

March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY   10605
askus@marchofdimes.com
http://www.marchofdimes.com/
Tel: 914-428-7100 888-MODIMES (663-4637)
Fax: 914-428-8203

National Organization for Rare Disorders (NORD)
P.O. Box 1968
(55 Kenosia Avenue)
Danbury, CT 06813-1968
orphan@rarediseases.org
http://www.rarediseases.org/
Tel: 203-744-0100 Voice Mail 800-999-NORD (6673)
Fax: 203-798-2291

Spina Bifida Association of America
4590 MacArthur Blvd. NW
Suite 250
Washington, DC 20007-4266
sbaa@sbaa.org
http://www.sbaa.org/site/c.gpILKXOEJqG/b.2016945/k.BE8D/Home.htm
Tel: 202-944-3285 800-621-3141
Fax: 202-944-3295

Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892

NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient's medical history.

Last updated December 03, 2004

Synonym: Arnold-Chiari Malformation
Table of Contents
What is Chiari Malformation?
Is there any treatment?
What is the prognosis?
What research is being done?
Organizations

What is Chiari Malformation?
Arnold-Chiari Malformation is a condition in which the cerebellum portion of the brain protrudes into the spinal canal. It may or may not be apparent at birth. Arnold-Chiari I type malformation usually causes symptoms in young adults and is often associated with syringomyelia, in which a tubular cavity develops within the spinal cord. Arnold-Chiari II type malformation is associated with myelomeningocele (a defect of the spine) and hydrocephalus (increased cerebrospinal fluid and pressure within the brain), which usually are apparent at birth. Myelomeningocele usually causes paralysis of the legs and, less commonly, the arms. If left untreated, hydrocephalus can cause mental impairment. Either type of Arnold-Chiari Malformation can cause symptoms of headache, vomiting, difficulty swallowing, and hoarseness.

Adults and adolescents who are unaware they have Arnold-Chiari I type malformation may develop headache that is predominantly located in the back of the head and is increased by coughing or straining. Symptoms of progressive brain impairment may include dizziness, an impaired ability to coordinate movement, double vision, and involuntary, rapid, downward eye movements.

Is there any treatment?
Infants and children with myelomeningocele may require surgery to repair protrusion of the meningeal sac into the spinal cord. Hydrocephalus may be treated with surgical implantation of a shunt to relieve increased pressure on the brain. Some adults with Arnold-Chiari Malformation may benefit from surgery in which the existing opening in the back of the skull is enlarged.

What is the prognosis?
Infants with very severe malformations may have life-threatening complications. Most patients who have surgery experience a reduction in their symptoms. Some patients may experience prolonged periods of relative stability.

What research is being done?
Research supported by the NINDS includes studies to understand how the brain and nervous system normally develop and function and how they are affected by disease and trauma. These studies contribute to a greater understanding of congenital birth defects, such as Arnold-Chiari Malformation, and open promising new doors to potential treatments.

Organizations

American Syringomyelia Alliance Project (ASAP)
P.O. Box 1586
Longview, TX   75606-1586
info@asap.org
http://www.asap.org/
Tel: 903-236-7079 800-ASAP-282 (272-7282)
Fax: 903-757-7456

March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY   10605
askus@marchofdimes.com
http://www.marchofdimes.com/
Tel: 914-428-7100 888-MODIMES (663-4637)
Fax: 914-428-8203

National Organization for Rare Disorders (NORD)
P.O. Box 1968
(55 Kenosia Avenue)
Danbury, CT 06813-1968
orphan@rarediseases.org
http://www.rarediseases.org/
Tel: 203-744-0100 Voice Mail 800-999-NORD (6673)
Fax: 203-798-2291

Spina Bifida Association of America
4590 MacArthur Blvd. NW
Suite 250
Washington, DC 20007-4266
sbaa@sbaa.org
http://www.sbaa.org/site/c.gpILKXOEJqG/b.2016945/k.BE8D/Home.htm
Tel: 202-944-3285 800-621-3141
Fax: 202-944-3295

Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892

NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient's medical history.

Last updated December 03, 2004