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Chiari Malformation

Medically reviewed by Last updated on Jul 4, 2022.

What is a Chiari malformation?

A Chiari malformation (CM) is a condition that affects the position of your brain within your skull. Your cerebellum (lower part of the brain) is pushed through the hole at the bottom of your skull. This blocks the normal flow of cerebral spinal fluid (CSF) between the brain and spinal canal. Your CM may be caused by problems that developed before you were born. For example, your brain may not have enough room if your skull is smaller than normal. A CM can also develop if too much CSF is drained from your spine, such as from an injury or infection.

What are the types of CM?

  • Type 1 is the most common. Part of the cerebellum is pushed through the hole at the bottom of your skull. You may not know you have this type until you are an adolescent or adult.
  • Type 2 causes the cerebellum and some of the brain stem to be pushed through the hole.
  • Type 3 is a severe form of CM. The entire cerebellum and brain stem are pushed through the hole and into the spinal canal. The spinal canal holds your spinal cord.
  • Type 4 is a rare form that occurs because the cerebellum is not completely developed.

What signs and symptoms may happen with a CM?

You may have no symptoms, or you may have any of the following:

  • Headache that is made worse when you cough or strain
  • Neck pain
  • Vision problems
  • Numbness or tingling in your arms or hands
  • Muscle weakness
  • Balance problems, dizziness, or ringing in your ears
  • Difficulty swallowing
  • Infants may gag, be irritable, drool more than usual, or vomit during feedings, have a stiff neck, or have slow weight gain

What other conditions may occur with a CM?

  • Hydrocephalus is a condition caused by too much CSF inside the brain. The CSF increases pressure within the skull. Hydrocephalus is more common with Type 2 CM.
  • Spina bifida is a condition that prevents the spinal cord and the bones around it from forming properly. Spina bifida can cause partial or complete paralysis. The condition is more common with Type 2 CM.
  • Syringomyelia is a condition that causes a cyst filled with CSF to form within the spinal cord. The cyst can damage the spinal cord. Damage can cause pain, weakness, and stiffness in your back, shoulders, arms, or legs.
  • Tethered cord syndrome is a condition that causes the spinal cord to attach to the spine. This can damage the muscles and nerves in your lower body.
  • Spinal curvature may also occur. Your spine may curve to the left or right, or it may bend forward. Spinal curvature is most common with Type 1 CM and in children.

How is a CM diagnosed?

Your healthcare provider will ask about your symptoms. He will also examine you for signs that may show you have a CM. You may also need the following tests:

  • An MRI scan may show brain tissue pushing out of your skull and into the spinal canal. You may be given contrast dye to help your brain and spinal canal show up better in the pictures. Tell the healthcare provider if you have ever had an allergic reaction to contrast dye. Do not enter the MRI room with anything metal. Metal can cause serious injury. Tell the healthcare provider if you have any metal in or on your body.
  • A cine MRI CSF flow study is an MRI that shows the flow of CSF from your brain to your spinal canal.

How is a CM treated?

You may not need any treatment if you do not have symptoms.

  • Medicines may be given to decrease the amount of CSF your body makes or to decrease CSF pressure. You may also be given prescription pain medicine, muscle relaxers, or antidepressants to relieve pain.
  • A shunt may be placed to drain extra CSF. This decreases pressure in the skull. CSF drains through a tube that goes from the skull into the chest wall or abdomen, where it is absorbed into the body.
  • Surgery may be needed if your CM is severe. Surgery may be done to remove some of your skull or spine. This may create more space for your cerebellum or relieve pressure on your spinal cord. You may need surgery to make your cerebellum smaller. Infants and young children may need surgery to move the spinal cord and close an opening. More than one surgery may be needed.

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

How can I manage my CM?

  • Sleep upright on a wedge pillow or an adjustable bed to help decrease headaches.
  • Massage or physical therapy may help relieve muscle spasms.
  • Avoid high-risk activities that could cause head and neck injury, such as roller coasters, skiing, and competitive sports.

When should I contact my healthcare provider?

  • Your signs or symptoms get worse.
  • You have questions or concerns about your condition or care.

When should I seek immediate care or call 911?

  • You have new or sudden trouble breathing.
  • You become less alert than usual, or you lose consciousness.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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Further information

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