An arachnoid cyst is a fluid-filled sac that develops in the meninges, the membranes that surround the brain and spinal cord. Arachnoid cysts are the most common type of brain cyst, and they are usually harmless. However, in some cases, they can cause symptoms such as headaches, seizures, and vision problems.
Types of Arachnoid Cysts
There are two main types of arachnoid cysts:
Congenital arachnoid cysts: These cysts are present at birth. They are thought to develop when there is a defect in the development of the meninges.
Acquired arachnoid cysts: These cysts develop later in life. They can be caused by a variety of things, including head injuries, infections, and tumors.
Symptoms of Arachnoid Cysts
Most people with arachnoid cysts do not have any symptoms. However, in some cases, cysts can grow large enough to cause pressure on the brain or spinal cord. This can lead to symptoms such as:
Headaches: Headaches are the most common symptom of arachnoid cysts. They are often worse when the person bends over or stands up quickly.
Seizures: Seizures can occur in people with arachnoid cysts, but they are not very common.
Vision problems: Vision problems can occur if the cyst is located near the optic nerves. These problems can include blurred vision, double vision, and loss of peripheral vision.
Weakness or numbness on one side of the body: Weakness or numbness on one side of the body can occur if the cyst is located near the motor cortex, the part of the brain that controls movement.
Speech problems: Speech problems can occur if the cyst is located near the speech center in the brain.
Personality changes: Personality changes can occur if the cyst is located near the frontal lobes of the brain.
Diagnosis of Arachnoid Cysts
The diagnosis of an arachnoid cyst is usually made based on a combination of medical history, physical examination, and imaging tests. Imaging tests that can be used to diagnose arachnoid cysts include:
Computed tomography (CT) scan: A CT scan is a quick and painless procedure that can show the size and location of a cyst.
Magnetic resonance imaging (MRI) scan: An MRI scan is a more detailed imaging test that can also show the size and location of a cyst.
Treatment of Arachnoid Cysts
Most arachnoid cysts do not need to be treated. However, if the cyst is causing symptoms or is growing in size, treatment may be necessary. Treatment options for arachnoid cysts include:
Observation: If the cyst is small and not causing any symptoms, it may be monitored with regular imaging tests.
Surgery: Surgery may be recommended for cysts that are causing symptoms or that are growing in size. There are two main types of surgery for arachnoid cysts:
Cyst fenestration: This is a procedure in which a small hole is made in the cyst to allow the fluid to drain.
Cyst resection: This is a procedure in which the entire cyst is removed.
Prognosis of Arachnoid Cysts
The prognosis for arachnoid cysts is usually good. Most cysts do not cause any long-term problems. However, some cysts can grow in size and cause problems later in life.
Arachnoid cysts are a common condition that can affect people of all ages. Most cysts do not need to be treated, but some may require surgery.
