What Is an Arachnoid Cyst?
cyst usually develops in the head, but may also develop around the spinal cord.
It is named an arachnoid cyst because it occurs in the space between the brain
(or spinal column) and the arachnoid membrane. This is one of three membrane
layers surrounding the brain and spine. If in the head, the cyst will grow
between the brain and skull or in pockets around the brain called ventricles.
The cyst is usually filled with cerebrospinal fluid (CSF). CSF is a naturally-occurring
protective fluid that surrounds the brain and spinal column. The fluid
accumulates in the cyst as the walls of the cyst do not permit drainage into
the CSF system.
in children are usually congenital, or present at birth. These cysts are called
primary arachnoid cysts. Arachnoid
cysts that are not congenital, but develop later in life, are called secondary arachnoid cysts. Primary
arachnoid cysts are more common than secondary arachnoid cysts. Men are more
likely to develop arachnoid cysts than females.
What Causes an Arachnoid Cyst?
arachnoid cysts, the congenital version, are usually caused by an abnormal
growth of the brain and spinal column while the baby is developing in utero.
This can be genetic. However, the exact cause of these growths is not known.
arachnoid cysts in both children and adults can have several causes. These
include trauma or injury to the head, meningitis, and tumors. They may also occur
as a reaction to brain surgery. Arachnoid cysts are most common in children.
Arachnoid Cyst Symptoms
are primarily asymptomatic. Most people don’t realize they have one until being
examined for other issues, such as head injuries.
develop if the cyst grows or is pressing on nerves or sensitive areas in the
brain or spinal cord. The most common symptoms of cysts in the brain include:
- problems hearing, seeing or walking
- neurological problems
- balance issues
of cysts on the spinal column include:
- back pain
- lack of feeling or tingling in the arms or legs
- muscle weakness or spasms
- problems controlling the bladder and bowels
Diagnosing Arachnoid Cysts | Diagnosis
Imaging is used
to diagnose an arachnoid cyst, primarily CT scan and MRI, to look at your brain
or spine. Usually a CT scan will find the cyst and it will be examined further
with an MRI to exclude other conditions, such as tumors.
Treating an Arachnoid Cyst
cyst with no symptoms or other complications may not be treated. A doctor will
monitor the cyst over time to watch for growth or changes in the cyst.
cysts, removal is common. Cysts in the brain may not be taken out with surgery
because of the risks. Rather, one of two procedures will be used. The first
involves a small incision near the cyst and insertion of an endoscope with a
small camera on the end. The endoscope is used to gently open the cyst,
allowing the fluid to drain. The fluid will mix in with the cerebrospinal fluid
and redistribute through the body. This procedure is called fenestration.
possible procedure for an arachnoid cyst includes putting a small tube, or
catheter, through an incision into the cyst. The shunt allows the fluid to
drain to another part of the body, such as the belly.
cysts on the spinal column, removal might be possible. If not possible,
fenestration or shunting are the best solutions.
Arachnoid Cyst Prognosis
treatment of a symptomatic cyst will resolve the symptoms. For asymptomatic
cysts, a doctor will continue to monitor the cyst and treat if symptoms appear,
but the affected patient should be able to enjoy a normal life with the cyst.
cysts are left untreated but are bleeding or growing rapidly, there could be permanent
neurological damage. This is a severe outcome.