Chiari & Dizziness

Dizziness is a common symptom of Chiari Malformation, a disorder in which the lower part of the skull is too small to house the brain. As a result, the brain protrudes into the spinal column, displacing the spinal fluid and causing a wide variety of symptoms. The vestibular system (the part of the brain that controls balance) is affected, causing dizziness. The dizziness can range from mild to extreme.

Origin of Chiari Malformation

• Chiari malformation is typically present at birth, but symptoms may not immediately appear. Doctors haven't pinpointed a specific cause for congenital Chiari Malformation, but believe it may be triggered by deficits in the mother's diet, exposure to harmful substances during fetal development, or genetic abnormalities that run in families. Chiari malformation may be acquired later in life when excessive fluid drains from the spine because of injury, infection or exposure to toxic substances.

Classifying Chiari Malformation

• There are four different types of Chiari Malformation. Type 1 is the most common, and is the only kind that can be acquired; the others are always congenital With Type 1, only the lower-most portion of the brain, the cerebellum, dips into the spinal column. Types 2 through 4 are usually diagnosed at birth or in early childhood, because they involve other parts of the brain and cause extensive neurological damage.

Diagnosing Chiari Malformation

• When symptoms such as dizziness appear, and Chiari Malformation is suspected, the doctor will conduct a physical exam and check the person's memory, balance, motor skills and other functions controlled by the cerebellum and spinal cord. Diagnostic tests such as x-ray and computed tomography (CT scan) may be ordered; however, magnetic resonance imaging (MRI) is the preferred method of imaging used to diagnose the disorder.

Why Chiari Causes Dizziness

• The vestibular system is found in the cerebellum. When the cerebellum dips into the spinal column as a result of Chiari Malformation, it puts immense pressure directly on the vestibular system, causing dizziness. Additionally, Chiari-related dizziness can be caused by the excessive amount of fluid that collects in the brain as a result of the malformation, or by increased pressure that travels through the cochlear aqueduct (a passageway that connects to a fluid-filled area of the inner ear).

Treatment for Chiari-Related Dizziness

• Treatment for Chiari-related dizziness is aimed at decreasing pressure on the brain by eliminating excess fluid. Diuretic medications, which help diminish fluid in the body by stimulating the kidneys to produce urine, may help, as would surgically implanting a shunt to promote drainage of cerebrospinal fluid around the brain. In extreme cases, a surgical procedure may be performed to create more room for the brain and spinal cord.