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Arachnoid Cysts Information Page

Synonym(s): Intracranial Cysts


Updated: January 3, 2005


Table of Contents
What are Arachnoid Cysts?
Is there any treatment?
What is the prognosis?
What research is being done?

What are Arachnoid Cysts?
Arachnoid cysts are cerebrospinal fluid-filled sacs that may develop between the surface of the brain and the cranial base or on the arachnoid membrane - one of the 3 membranes that cover the brain and the spinal cord. Most cases begin during infancy, however onset may be delayed until adolescence. Symptoms of an arachnoid cyst are related to the cyst size and location. Small cysts are usually asymptomatic and are discovered only incidentally. Large cysts may cause cranial deformation or macrocephaly (enlargement of the head), producing such symptoms as headaches, seizures, hydrocephalus (excessive accumulation of cerebrospinal fluid), increased intracranial pressure, developmental delay, and behavioral changes. Other symptoms may include hemiparesis (weakness or paralysis on one side of the body) and ataxia (lack of muscle control). Arachnoid cysts most often occur in males.

Is there any treatment?
Treatment for arachnoid cysts is symptomatic. When symptoms warrant, the surgical placement of a shunt may be required to decompress (remove pressure from) the cyst.

What is the prognosis?
Untreated, arachnoid cysts may cause permanent severe neurological damage due to the progressive expansion of the cyst(s) or hemorrhage (bleeding). With treatment most individuals with arachnoid cysts do well.

What research is being done?
The NINDS supports research on brain and nervous system disorders such as arachnoid cysts. The goal of this research is to increase scientific understanding of these disorders and to find ways to prevent and treat them.

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

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

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