Understanding Chiari Malformation


Chiari malformation is a rare condition in which part of the lower skull is too small which forces the cerebellum to be pushed down into the spinal column. The cerebellum is the part of the brain that controls human movement, muscle control, equilibrium, and balance. Primary Chiari malformation occurs during fetal development. Inadequate intake of vitamins and minerals during pregnancy causes pressure to be placed on the fetus' cerebellum which, in turn, blocks the flow of cerebrospinal fluid (the fluid that surrounds and protects the brain and spinal cord). Chiari malformation can also occur later in life due to trauma, disease, or infection; this is called secondary Chiari malformation.

There are four types of Chiari malformation: Type I, Type II, Type III, and Type IV. Type I is found in children and is the most common type. In Type I, part of the cerebellum extends into an opening at the base of the skull. Oftentimes, there are no symptoms of Type I Chiari malformation; in fact, many people that have the condition don't even know it. If symptoms do present, they include sudden pain in the neck, dizziness, sleep apnea, and trouble swallowing. Type II is the classic form of Chiari malformation and found in children born with spina bifida. Spina bifida is a condition in which the spinal cord doesn't completely form and close correctly resulting in damage to the spinal cord and nerves. Children born with type II Chiari malformation also have hydrocephalus (cerebrospinal fluid in the brain or "water on the brain"). Type III is very rare and involves protrusion of the cerebellum and brain stem into the spinal cord. This causes severe neurological defects and has the highest mortality rate of the four types. Type IV is also very rare and consists of an underdeveloped cerebellum. It sometimes is associated with exposed parts of the skull and spinal cord.

Symptoms of Chiari malformation include, but are not limited to, headaches (especially after coughing, sneezing or straining), neck pain, hearing problems, dizziness, difficulty swallowing, depression, sleeping problems, curvature of the spine (scoliosis or kyphosis), tinnitus, vomiting, muscle issues, difficulty with fine motor skills, etc. Women are more likely to suffer from Chiari malformation than men.

A thorough evaluation is needed to test for Chiari malformation including checking balance, reflexes, and fine-motor skills. An x-ray, MRI, and CT scan should also be performed. Increased image testing has led to a quicker and more accurate diagnosis of Chiari malformation. Medication may be used to help control pain. Surgery is the most common treatment for Chiari malformation. It can correct the defect or stop the progression. A small portion of the spinal column may be removed to relieve pressure.