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What are arachnoid cysts?
Added Previous answer is good... Can occur anywhere between surface of the inner brain 'cover' to arising in the spinal cord; like all cysts they are fluid-filled 'bubbles/bal…loons" that usually --but not always-- put pressure on the brain or spinal cord and cause worsening/permanent nerve damage. There are basically two different types of subarachnoid cysts: either present at birth, and sometimes demonstrate neurological symptoms before the age of 20 years old... Or can be as a result of brain trauma... Not all of these cysts require surgical intervention... just those causing symptoms. With todays minimally invasive "microsurgical" techniques, neurosurgeons are really a lot more successful in removing the "sac" that must be removed to prevent the recurrence of the cyst. Refer to the website: http://www.ninds.nih.gov/disorders/arachnoid_cysts/arachnoid_cysts.htm for a complete review of what you should know about this disease process... Gordon Answer 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. (MORE)