What are arachnoid cysts?

Arachnoid cysts are sacs occupied by cerebrospinal fluid that are found amidst the spinal cord or brain and the arachnoid membrane.

  • Primary – these are already present at birth and form due to developmental irregularities in the spinal cord and brain during the early weeks of gestation
  • Secondary – these develop from a head injury, tumor, meningitis or as an issue after brain surgery.

The symptoms and when they start is usually based on the site and size of the cyst. Generally, individuals with the cysts end up with symptoms before the age of 20 and particularly during the initial year, yet some do not have any symptoms.


The symptoms and when they start is usually based on the site and size of the cyst.

What are the indications?

The usual indications of arachnoid cysts that develop around the brain include:

  • Nausea
  • Headache
  • Seizures
  • Vomiting
  • Hearing and visual disturbances
  • Vertigo
  • Issues with walking and balance

As for the cysts that form around the spinal cord, it causes compression of the nerve roots and spinal cord itself which triggers symptoms such as:

  • Progressing back and leg pain
  • Tingling or numbness in the arms or legs

Management of arachnoid cysts

Treatment usually depends on the site and size of the cyst. For a small-sized cyst that does not disrupt the surrounding tissues and there are no symptoms, the doctor will refrain using any treatment.

In the previous years, shunts are used by the doctor to drain out of the fluid. With the availability of microneurosurgical techniques and endoscopic tools, minimally invasive surgery is possible. During such procedures, the doctor might decide to surgically remove the membranes of the cyst or open it to allow drainage of fluid into the cerebrospinal fluid to be absorbed.