Chiari Malformations Chiari Malformations

Chiari Malformations

Chiari malformations are structural defects that occur at the base of the skull, at the back of the head. These malformations range in severity. The condition occurs when the cerebellum, the part of the brain that controls balance, memory and cognition, slips or partially slips into the opening in the brain where the spinal cord passes through. This misalignment puts pressure on the cerebellum and it blocks, or interferes with the flow of cerebrospinal (CS) fluid.


Symptoms vary to begin with and may change depending on the amount of compression of surrounding tissues and nerves and the buildup of cerebrospinal (CS) fluid. There are four categories of Chiari malformations.

Type I: The most common type, it is possible that no symptoms are experienced at all. If symptoms do develop, a severe headache, especially after sudden movement (coughing or sneezing, for example), is the most predominant; you might also experience neck pain, hearing and balance problems, and vomiting.

Type II: Both the cerebellum and the brain stem tissue protrude into the space opening where the spinal cord enters. Infants may have difficulty swallowing, excessive drooling, a weak cry, breathing problems, arm weakness, developmental delays and an inability to gain weight.

Another condition, called myelomeningocele, is often associated with type II malformations. This is a form of spinal bifida. Other related conditions are syringomyelia and tethered cord syndrome.

Types III and IV are rare and severe.

If your infant is showing any of the symptoms of a Chiari malformation, which can be life-threatening in some cases, call your physician immediately.



Chiari malformations found in infancy are thought to be a result of a genetic mutation that takes effect during fetal development. A maternal diet that lacks certain nutrients is also an influence. Research is being done on exact causes.

If symptoms develop later in life, they can still be the result of a more minor or type I Chiari malformation from birth, or they might be the result of an injury or infection that affects this area of the brain and causes the change.


Living Better

If you have been diagnosed with a Chiari malformation, but do not have any symptoms, it is likely that your physician will want to continue to monitor your condition for any progression. The test most generally used to track any changes would be magnetic resonance imaging (MRI) scans performed at certain intervals.

If you or your child has had surgery to correct the condition, you will be making follow-up visits to make sure that the flow of cerebrospinal fluid has been restored. Imaging tests will be performed to check on surgical results and healing.

There may be a support group in your area for people who are living with this condition, or who have a child in whom the condition or related conditions have been diagnosed. Meeting with knowledgeable professionals and with others in circumstances similar to yours can help ease anxiety and provide information or insights on managing symptoms or negotiating setbacks.


Exams and Tests

Even though this is a condition that is most severe if diagnosed at birth, there is as yet no pre-natal testing available. Some malformations can be seen during ultrasound. If an infant is born with spinal bifida, testing for a Chiari malformation will be performed.

Your physician at St. Luke’s will use a number of tests, including a physical exam, to determine what is causing your or your child’s symptoms. A magnetic resonance imaging (MRI) scan is the test most often used, as it will produce a three-dimensional image or two-dimensional slice of the tissues, organs, bones and nerves in the affected area. Bone abnormalities most often associated with a Chiari malformation can be seen by X-rays, although the tissue malformation itself will not be seen by these tests. A computed tomography (CT) scan can show evidence of any hydrocephalus or bone abnormalities.

If it is you or an older child who is symptomatic, your physician will also be able to employ tests that measure functions controlled by the cerebellum, which include memory, cognition and balance. Functions controlled by the spinal cord — which include touch, reflexes, sensation and motor skills — can also be evaluated in older patients.



Even if a Chiari malformation is found during testing for another condition, no treatment for it is necessary if you are not experiencing any symptoms. Your physician will likely want you to be monitored for any growth or change in the condition. If you have symptoms such as headache or neck pain, simple pain relief medications might be prescribed.

In most cases, the only remedy for severe symptoms that result from this condition is surgery. If the condition is caught during a routine pregnancy ultrasound, there has been success, according to the National Institutes of Health, with prenatal surgery that repositions the spinal cord and closes up the opening in the back of the neck. The goal of this surgery would be to restore the cerebellum and brain stem to a more normal alignment, preventing severity of symptoms and the occurrence of other conditions, including hydrocephalus.