ARACHNOID CYSTS - Watsons Health


An arachnoid cyst is a cyst that occurs in the space between your brain, or spinal column, and your arachnoid membrane. Oftentimes, this cyst develop in your head and it will grow between your brain and skull or in pockets around your brain called ventricles.

Arachnoid cysts are usually filled with cerebrospinal fluid (CSF). CSF is a naturally occurring protective fluid that surrounds your brain and spinal column. The walls of an arachnoid cyst don’t allow this fluid to drain into your CSF system, causing it to accumulate inside.

Arachnoid cyst in children are usually congenital, or present at birth. These are called primary arachnoid cyst and the most common type. On the other hand, secondary arachnoid cyst develops later in life.

Arachnoid cysts are usually have no signs and symptoms (asymptomatic). In that case, most people who have an arachnoid cyst don’t realize it until they’re examined for other issues, such as head injuries.

In some cases, arachnoid cysts do cause symptoms. These depends on the location and size of the cyst. For example, symptoms may develop if you have a cyst that presses on nerves or sensitive areas of your brain or spinal cord. If it’s located in your brain, the cyst may produce one or more of the following symptoms:

  • Headache
  • Dizziness
  • Nausea
  • Vomiting
  • Lethargy
  • Seizures
  • Problems Hearing, Seeing, or Walking
  • Balance Issues
  • Developmental Delay
  • Dementia

If it’s located in your spinal column, it may cause symptoms such as:

  • Back Pain
  • Scoliosis
  • Muscle Weakness or Spasms
  • Lack of Feeling or Tingling in Your Arms or Legs
  • Problems Controlling Your Bladder or Bowels

Contact your doctor if you develop these symptoms.


The doctor will likely order imaging tests if he or she suspects someone is having an arachnoid cyst. For example, they may use CT and MRI scans to look at your brain or spine.



Your doctor may advise you to leave your arachnoid cyst untreated if it’s not causing any symptoms or other complications. However, your doctor will likely monitor the cyst over time to watch for potential growth or other changes. They may recommend treatment if the cyst begins to cause problems.

If you have an arachnoid cyst in your brain that’s causing symptoms, your doctor will likely drain it. They may recommend one of two procedures:

  • First procedure– The doctor will make a small incision near the cyst and insert an endoscope with a small camera on the end. This endoscope is used to gently open the cyst, allowing the fluid inside to drain into your CSF system, where it will be redistributed through your body. This procedure is called fenestration.
  • Second procedure-The doctor will insert a shunt into the cyst. This will allow the fluid inside to drain to another part of your body, such as your belly.

If you have a symptomatic cyst in your spinal column, your doctor may recommend surgery to remove it completely. If that’s not feasible, they may use fenestration or shunting to drain it.

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