In a Chiari malformation, part of the cerebellum is pushed down into the spinal canal because the skull is misshapen or abnormally small. The spinal fluid may not be able to flow freely, causing blocked signals between the body and the brain or a build up of fluid.
Type I occurs as the skull and brain are growing. Patients with Chiari malformation type I may not realize they have the condition until late childhood or adulthood. Often it is detected while the patient is being tested for another disorder. Common symptoms include headaches after coughing, sneezing or straining, neck pain, dizziness and balance problems, poor hand coordination, vision issues and difficulty swallowing. Less common symptoms include tinnitus, slow heart rhythm, scoliosis and sleep apnea.
Although, Chiari malformation type I can have difficult symptoms, it is not as serious as type II or type III, which are congenital. Type II is related to a form of spina bifida in which the spinal canal and backbone are not closed before birth. In type III, a portion of the cerebellum or brain stem protrudes through an opening in the back of the skull.
Some patients with Chiari malformation type I do not require treatment beyond regular doctor examination or pain medication. Other patients may require surgery to relieve pressure on the brain and spinal cord, and allow the spinal fluid to flow naturally.