Arnold-Chiari Syndrome
(Arnold-Chiari Malformation; Type II Chiari Malformation; Cerebellomedullary Malformation Syndrome)
Definition
Arnold-Chiari syndrome is a defect in the formation of the cerebellum (the small, bottom portion of the brain) and brainstem. This defect can slow the flow of spinal fluid. In some cases, it is accompanied by a myelomeningocele, which is a form of spina bifida. There are three types of Chiari Syndrome, with different degrees of severity. Type 2 (Arnold Chiari syndrome) is the one associated with spina bifida.
Brain Stem and Cerebellum
Causes
Arnold-Chiari syndrome occurs during brain development before birth. The indented bony space in the lower rear of the skull is smaller than normal, so the cerebellum and brainstem are pushed downward. The reason the brain does not develop normally is not well understood.
Risk Factors
The following conditions are commonly associated with Arnold-Chiari syndrome, but are not thought to be a cause of the disorder:
- Spina bifida
- Hydrocephalus
Symptoms
Symptoms exhibited in infants may include:
- Vomiting
- Mental impairment
- Weakness
- Paralysis of the limbs
Symptoms in adolescents are usually milder and may include:
- Dizziness
- Fainting
- Weakness of the legs
- Headaches
- Double vision
- Deafness
- Swelling of the optic nerve region
- Rapid eye movement
- Lack of muscular coordination
- Uncontrolled shaking or trembling
- Walking problems
- Numbness or tingling in the extremities
Diagnosis
Your doctor will ask about symptoms and medical history, and perform a physical exam. He or she will also perform and MRI and/or CT scan to view the inside of the brain.
Cerebrospinal fluid (CSF) is a vital fluid that surrounds the brain and spine. Special studies to evaluate the flow of CSF may be performed.
Treatment
Talk with your doctor about the best treatment plan. Treatment options include the following:
Treatment of Symptoms
Depending on the symptoms associated with Arnold-Chiari syndrome, other treatments may be beneficial. For instance, physical or occupational therapy can help improve muscular coordination and trembling. In addition, braces or a wheelchair may be needed. Speech therapy may also be beneficial.
Prevention
There is no known way to prevent Arnold-Chiari syndrome. Parents of a child with this condition may benefit from genetic counseling.
March of Dimes Birth Defects Foundation
National Institute of Neurological Disorders and Stroke
Canadian Neurological Sciences Federation
Health Canada
Arnold-Chiari malformation. DynaMed website. Available at: http://dynamed102.ebscohost.com/Detail.aspx?id=115525. Accessed May 23, 2007.
Arnold-Chiari syndrome. Arkansas Spinal Cord Commission website. Available at: http://www.spinalcord.ar.gov/Publications/FactSheetsPDF/ArnoldChiari.pdf. Accessed May 23, 2007.
Chiari malformation. Comer Children’s Hospital University of Chicago at: http://www.uchicagokidshospital.org/online-library/content=P02592.
Chiari malformation information page. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/chiari/chiari.htm. Accessed May 23, 2007.
Kinsman SL. Chiari malformation. In: Gilman S, ed. MedLink Neurology. San Diego, CA: MedLink Corporation. Available at: http://www.medlink.com. Accessed August 10, 2007.
Chiari Malfomation Information Page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/chiari/chiari.htm. Accessed July 24, 2010.
Last reviewed September 2011 by Marjorie Bunch, 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.
