Chiari MalformationChiari (kee-AR-ee) malformation (CM) includes a complex group of disorders characterized by herniation of the cerebellum through the large opening in the base of the skull (foramen magnum) into the spinal canal. The herniated tissue blocks the circulation of cerebrospinal fluid in the brain and can lead to the formation of a cavity (syrinx) within the spinal cord. There are three main types of CM. CM1, the simplest and most prevalent form, is generally considered to be a congenital malformation, although acquired cases are recognized. It is rarely apparent at birth.
Patients with CM1 may experience no symptoms. When symptoms are present, they usually do not appear until adolescence or early adulthood, but can occasionally be seen in young children. The majority of patients complain of severe headache and neck pain. Other common symptoms are dizziness, vertigo, disequilibrium, visual disturbances, ringing in the ears, difficulty swallowing, palpitations, sleep apnea, muscle weakness, impaired fine motor skills, chronic fatigue and painful tingling of the hands and feet. Because of this complex symptomatology, patients with CM1 are frequently misdiagnosed.
How common is Chiari malformation?
Until recent years, CM1 was regarded as a rare condition. With the increased availability of magnetic resonance imaging, the number of reported cases has risen sharply. Current estimates range from 200,000 to 2 million Americans with the condition. Genetic studies spearheaded by Dr. Milhorat support a hereditary tendency with a transmissibility rate of 12 percent. Women are affected three times more often than men. Approximately 3,500 Chiari operations are performed each year in the United States.
People with Chiari malformation type I also can experience:
Neck pain (running down the shoulders at times)
Unsteady gait (problems with balance)
Poor hand coordination (fine-motor skills)
Numbness and tingling of the hands and feet
Dizziness
Difficulty swallowing (sometimes accompanied by gagging, choking and vomiting)
Vision problems (blurred or double vision)
Slurred speech
Less often, people with Chiari malformation may experience:
Ringing or buzzing in the ears (tinnitus)
Poor bladder control
Chest pain, in a band-like pattern around the chest
Curvature of the spine (scoliosis) related to spinal cord impairment
Abnormal breathing — specifically, sleep apnea characterized by periods of breathing cessation during sleep
Some people have occasional "dropping" episodes — feeling faint and unexpectedly collapsing to the floor, losing consciousness for a few seconds.
All of this information was taken from The Chiari Institute website as well as the Mayo Clinic website. There is a ton more information out there but I wanted to put a brief (haha) explaination up for you.