A head CT scan or a head MRI is often ordered when someone suffers a head injury. Imaging allows doctors to determine whether or not there are serious problems that resulted from a blow to the head, such as a cracked skull or bleeding in the brain. Sometimes, however, an incidental finding of Chiari malformation may be discovered. Here's what you need to know if you've been told of an incidental finding of Chiari malformation in a brain imaging study. 

What is Chiari Malformation? 

Chiari malformation is a defect in the structure of the base of the skull which can cause the cerebellar tonsils to herniate into the foramen magnum, which is the opening for the spinal cord at the base of the skull. This can cause a reduction in the flow of cerebral spinal fluid and/or pressure on the brain stem. Symptoms of this condition can include pressure headaches, numbness and tingling, sleep apnea, difficulty swallowing, vision problems, problems with balance and coordination, and a wide range of other seemingly unrelated symptoms throughout the body.

However, Chiari malformation can be symptomatic or asymptomatic. Sometimes, people with Chiari malformation never experience symptoms, but it is still crucial for those with asymptomatic Chiari malformation to be seen by a neurosurgeon on a regular basis. The reason for this is because Chiari malformation can cause syringomyelia to develop. 

What is Syringomyelia? 

When the cerebral spinal fluid does not flow properly, a pocket of fluid called a syrinx can form. This condition is called syringomyelia. In fact, syringomyelia is seen in 65-80% of patients with Chiari malformation. Symptoms of syringomyelia include muscle weakness in the legs, scoliosis, and problems with bladder and bowel functionalities. This is a progressive condition, so finding it as soon as it develops is crucial.

Further MRI imaging to locate problematic areas and syringomyelia should include a cine MRI, which is essentially a movie image of the flow of cerebral spinal fluid in the head and through the spine. Typically, neurosurgery for Chiari malformation can improve the flow of cerebral spinal fluid, which should reduce the syrinx. Alternatively, a neurosurgeon can drain the syrinx with the placement of a shunt. 

In conclusion, you will need to see a neurosurgeon for a thorough assessment of your incidental Chiari malformation and possible syringomyelia. He or she may recommend on going evaluations at regular intervals depending on the results of your imaging studies or ask you to return should you experience any of the typical symptoms of Chiari malformation and/or syringomyelia.