A Chiari malformation is a structural defect in the cerebellum, the part of the brain that controls balance. It occurs when the space below the back of the skull is too small and brain tissue gets pushed down into the spinal canal.
There are three forms of Chiari malformation:
- Type I – the most common form. Because it often does not cause symptoms, type 1 is often discovered by accident while a person is being examined or treated for another condition. Most patients are in their mid- to late-30s at the time of diagnosis.
- Type II, or Arnold-Chiari malformation – almost always accompanies myelomeningocele (a form of spina bifida in which the backbone and the spinal canal don’t close properly before birth). This form of Chiari malformation is usually diagnosed in utero (during pregnancy), right after birth or in early infancy.
- Type III – the most serious but rare form, usually diagnosed during childhood. It can cause serious neurological defects and carries a higher risk of death than type I or type II.
Chiari malformation: what you should know
- Not only do symptoms vary from person to person, but each person’s symptoms can change over time depending on the amount of pressure on tissues and nerves. That unpredictability — along with the lack of a reliable diagnostic test — can make Chiari malformation very difficult to diagnose.
- Although some people with Chiari malformation don’t have any symptoms, those who do almost always have at least five symptoms. And more than half experience at least 13 of the known symptoms.
- Headaches are by far the most common symptom, affecting almost everyone with Chiari malformation.
How can I find out if I have a Chiari malformation?
See your primary care doctor promptly if you experience any of these symptoms — especially if you have five or more at the same time:
- Headache that starts in the back of the head and spreads forward, brought on by coughing, sneezing, straining or other actions
- Balance problems
- Difficulty swallowing (dysphagia) or speaking – one of the most common symptoms in young children with Chiari malformation
- Extreme pain in the neck and shoulders
- Loss of bladder and bowel control – another common symptom in children
- Numbness, weakness or other abnormal feelings in the arms or legs
- Poor hand coordination
- Tinnitus (ringing or buzzing in the ears)
- Sleep apnea – a large percentage of both adults and children with Chiari malformation experience some form of sleep apnea
- Spinal curvature (scoliosis) – Chiari malformation is common in children and adolescents with scoliosis
- Vision problems – common eye problems include nystagmus (rapid, involuntary movement of the eyes), blurred or double vision, and sensitivity to light
Care for Chiari malformation at Rush
If your primary care doctor suspects a Chiari malformation, you may be referred to a neurosurgeon at Rush for further evaluation and care.
Neurosurgeons at Rush have decades of expertise with Chiari malformation. They will work with you to develop a treatment plan based on your specific symptoms and the nature of your malformation.
There are typically three approaches to treating Chiari malformation:
- Watchful waiting: If you have no symptoms or only mild symptoms, or if you don’t have a definite diagnosis, the best option may be to wait and see. Your doctor will monitor you for changes in your health, including new or worsening symptoms.
Treat symptoms individually: Your doctor may recommend this approach in the following instances:
- Your symptoms are too bothersome to ignore but not severe enough to justify surgery
- You don’t want surgery or aren’t healthy enough to have surgery
- You have not received a definite diagnosis of Chiari malformation
Surgery: Fewer than half of people diagnosed with Chiari malformation have surgery. It is typically reserved for the most severe forms, to reduce or stabilize symptoms and prevent the condition from worsening.
- Posterior fossa decompression, the most common surgery for Chiari malformation, relieves pressure in the area of the skull base where the spinal cord meets the brain.
- Other brain or spinal cord surgeries may be needed to relieve pressure on the spinal cord or make additional room for your brain. If so, your neurosurgeon will discuss the procedures with you.