Rare Diseases 2022

Aracnóide cyst: what é, symptoms, causes and treatment

Table of contents:

Aracnóide cyst: what é, symptoms, causes and treatment
Aracnóide cyst: what é, symptoms, causes and treatment

The arachnoid cyst is a benign lesion formed by cerebrospinal fluid, which develops between the arachnoid membrane and the brain. In rarer cases it can also form in the spinal cord.

These cysts can be primary or congenital when they are formed during the baby's development during pregnancy, or secondary, when they form throughout life due to trauma or infection, being less common.

Arachnoid cyst is usually not serious or dangerous, and should not be confused with cancer, and may even be asymptomatic. There are three types of arachnoid cysts:

  • Type I: small and asymptomatic;
  • Type II: are medium and cause temporal lobe displacement;
  • Type III: are large and cause displacement of the temporal, frontal, and parietal lobes.

What are the symptoms

Usually these cysts are asymptomatic and the person only discovers that they have the cyst when they undergo a routine exam or the diagnosis of some disease.

However, there are cases where arachnoid cysts have some risks and cause symptoms that depend on where they develop, their size or if they compress a nerve or any sensitive area of ​​the brain or spinal cord:

Cyst located in the brain Cyst located in the spinal cord
Headache Back pain
Dizziness Scoliosis
Nausea and vomiting Muscle weakness
Difficulty walking Muscle spasms
Unconsciousness Insensitivity
Hearing or vision problems Tingling in arms and legs
Balance problems Difficulty controlling the bladder
Development delay Difficulty controlling bowels

Possible causes

Primary arachnoid cysts are caused by abnormal growth of the brain or spinal cord during the baby's development.

On the other hand, secondary arachnoid cysts can be caused by various situations, such as injuries or complications to the brain or spinal cord, infection such as meningitis or tumors.

How the treatment is done

If the arachnoid cyst does not cause symptoms, no treatment is necessary, however, it should be monitored periodically using a CT scan or an MRI to see if it increases in size or if there is any change in morphology.

If the cyst causes symptoms, it should be evaluated to see if surgery is necessary, which is usually safe and produces good results. There are 3 types of surgeries:

  • Permanent drainage system, which consists of placing a permanent device that drains fluid from the cyst to the abdomen, in order to reduce pressure on the brain, which fluid is reabsorbed by the body;
  • Fenestration, which consists of making a cut in the skull to access the cyst, and in which incisions are made in the cyst so that the fluid is drained and absorbed by the surrounding tissues, thus reducing the pressure it exerts on the brain. Although it is more invasive than the previous system, it is more effective and definitive.
  • Endoscopic fenestration, which is an advanced technique that has the same benefits as fenestration, but is less invasive because it is not necessary to open the skull, being a quick procedure. In this procedure, an endoscope is used, which is a type of tube with a camera at the end, which drains the fluid from the cyst to the brain.

Thus, one should talk to the doctor, in order to understand which procedure is most appropriate for the type of cyst and the symptoms presented, in addition to factors such as age, location or size of the cyst, for example.

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