DESCRIPTION
Arachnoid cysts are cerebrospinal fluid covered by arachnoidal cells and collagen that may develop between the surface of the brain and the cranial base or on the arachnoid membrane, one of the three membranes that cover the brain and the spinal cord.
CAUSES
• The exact cause of arachnoid cysts is not known. Researchers believe that most cases of arachnoid cysts are developmental malformations that arise from the unexplained splitting or tearing of the arachnoid membrane.
• In some cases, arachnoid cysts occurring in the middle fossa are accompanied by underdevelopment (hypoplasia) or compression of the temporal lobe. The exact role that temporal lobe abnormalities play in the development of middle fossa arachnoid …show more content…
• On the other hand, a number of symptoms may result from large cysts:
Cranial deformation or macrocephaly (enlargement of the head), particularly in children
Cysts in the suprasellar region in children have presented as bobbing and nodding of the head called bobble-head doll syndrome.
• Cysts in the left middle cranial fossa have been associated with ADHD in a study on affected children.
Headaches. A patient experiencing a headache does not necessarily have an arachnoid cyst.
A study found 18% of patients with intracranial arachnoid cysts had non-specific headaches. The cyst was in the temporal location in 75% of these cases.
Seizures
Hydrocephalus (excessive accumulation of cerebrospinal fluid)
• Increased intracranial pressure
• Developmental delay
• Behavioral changes
• Nausea
PRECAUTIONS/PREVENTION
Most arachnoid cysts are asymptomatic and do not require treatment. Treatment may be necessary when symptomatic. A variety of procedures may be used to decompress (remove pressure from) the cyst.
• Surgical placement of a cerebral shunt.
• An internal shunt drains into the subdural