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An arachnoid cyst is a fluid-filled sac that grows between the arachnoid membrane and the brain or spinal cord. The arachnoid is one of the layers of tissue (membranes) that cover the brain and spinal cord.
This type of cyst can form as a baby grows in the uterus. Or the cyst may form later in life from an illness or head injury.
Most babies don't have any symptoms. Some children may have symptoms later in life. It depends on where the cyst is and how big it is.
If your child does have symptoms, they may include:
If the cyst presses on the spinal cord, your child may have:
Treatment may not be needed if there aren't any symptoms. Your child may have follow-up appointments and regular MRI tests. This is to see if the cyst is growing.
Some cysts are large or are in a place where they cause symptoms. A cyst that puts pressure on the brain or spinal cord may cause delays in development. It could cause permanent injury. Treatment may be a surgery to place a shunt or to remove part or all of the cyst. This may allow the fluid to drain.
Follow-up care is a key part of your child's treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if your child is having problems. It's also a good idea to know your child's test results and keep a list of the medicines your child takes.
Current as of: August 25, 2022
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Steven C. Schachter MD - Neurology & Colin Chalk MD, CM, FRCPC - Neurology
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