Symptoms vary depending on the size and location of the arachnoid cyst and can go undetected for years. Small cysts – and even many large ones – often exist without causing symptoms. However, if the cyst grows large enough it can put pressure on surrounding parts of the brain and spinal cord, resulting in the onset of symptoms.
Most common symptoms include:
- Nausea and/or vomiting
- Behavioral changes
- Hearing and vision problems
- Balance problems while walking or standing
- Weakness or paralysis on one side of the body
Causes of an arachnoid cyst
While a definitive cause is unknown, most arachnoid cysts are present at birth and believed to be the result of developmental abnormalities. Several familial or hereditary conditions – such as Cockayne syndrome and Menkes syndrome –increase potential risk. Researchers believe arachnoid cysts form when the arachnoid membrane surrounding the brain suddenly splits or tears, trapping cerebrospinal fluid.
In adults, arachnoid cysts occur four times more often in men than in women and can form as a result of brain surgery or in conjunction with a brain tumor, infection or injury.