Arachnoid Cysts (Intracranial Cysts)
About Arachnoid Cysts
Arachnoid cysts are characterised by cerebrospinal sacs filled with fluid, and they can grow between the cranial base and the brain surface. They can also develop on the arachnoid membrane. In most cases, arachnoid cysts begin in infancy, but sometimes the onset is delayed until the teenage years.
What symptoms characterise arachnoid cysts?
The symptoms of an arachnoid cyst vary depending on the location and size of the cyst.
Small cysts
Small cysts normally show no symptoms, and are only discovered during diagnosis for other conditions.
Large cysts
Large cysts can cause deformation of the cranium or head enlargement (known as macrocephaly). These problems can produce symptoms such as:
- Seizures
- Headaches
- Disproportionate build up of the cerebrospinal fluid (hydrocephalus)
- Increased pressure within the cranium
- Delays in development
- Changes in behaviour
- Paralysis or weakness in one particular side of the body (hemiparesis)
- Lack of control in the muscles (ataxia)
Arachnoid cysts occur most commonly in males.
How are the cysts treated?
Treatment methods for arachnoid cysts depend upon the symptoms. When the symptoms require it, a shunt may be surgically placed to eliminate pressure from the cyst.
What is the prognosis for arachnoid cysts?
If left without treatment, arachnoid cysts can cause severe neurological damage permanently. This is due to the progression of the expanding cyst, or haemorrhage. However, when the cysts are treated, most patients recover very well.