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.

Arnold-Chiari Syndrome

(Arnold-Chiari Malformation; Type II Chiari Malformation; Cerebellomedullary Malformation Syndrome)
by Krisha McCoy, MS
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.

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:

Symptoms

Symptoms exhibited in infants may include:

  • Mental impairment
  • Paralysis of the limbs
  • Vomiting
  • Weakness

Symptoms in adolescents are usually milder and may include:

  • Deafness
  • Dizziness
  • Double vision
  • Fainting
  • Headaches
  • Lack of muscular coordination
  • Numbness or tingling in the extremities
  • Rapid eye movement
  • Swelling of the optic nerve region
  • Uncontrolled shaking or trembling
  • Walking problems
  • Weakness of the legs
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:

Surgery

Surgery is usually required to correct any obstruction in the brain.

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.

Last reviewed: September 2010 by Rimas Lukas, MD.

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