Chiari Malformation

What is Chiari malformation?

Chiari malformation is a rare condition characterized by brain tissue that extends into the spinal canal. It occurs when part of the skull is abnormally small or misshapen, pressing on the brain and forcing it downward. There are three types:

Chiari malformation type I, which develops as the skull and brain are growing and is the pediatric form of the disease
Chiari malformation type II, which is present at birth (congenital)
Chiari malformation type III, which is also present at birth (congenital) and is the rarest and most severe form of the disease

What are the symptoms of Chiari malformation?

In Chiari malformation type I, signs and symptoms usually appear during late childhood or adulthood.

Headaches, generally occurring after sudden coughing, sneezing or straining
Neck pain
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) and speech problems, such as hoarseness
Ringing or buzzing in the ears (tinnitus)
Slow heart rhythm
Scoliosis, related to spinal cord impairment
Abnormal breathing, such as central sleep apnea, characterized by periods of breathing cessation during sleep

In Chiari malformation type II, a greater amount of tissue extends into the spinal canal compared with Chiari malformation type I. Thus, the signs and symptoms of this type can include:

Issues related to a form of spina bifida called myelomeningocele
Changes in breathing pattern
Swallowing problems, such as gagging
Quick downward eye movements
Weakness in arms

In Chiari malformation type III, a portion of the lower back part of the brain (cerebellum) or the brainstem extends through an abnormal opening in the back of the skull. This type of Chiari malformation has a higher mortality rate and may also cause neurological problems and associated symptoms.

What causes Chiari malformation?

Chiari malformation type I occurs when the section of your skull containing a part of your brain (cerebellum) is too small or is deformed, thus putting pressure on and crowding your brain. The lower part, or tonsils, of the cerebellum are displaced into your upper spinal canal. Chiari malformation type II is nearly always associated with a form of spina bifida called myelomeningocele.

How is Chiari malformation diagnosed?

A thorough examination, a review of medical history, and observation of the characteristics of Chiari malformation can lead to a diagnosis. Imaging tests, such as a MRI, X-ray, and CT scan can help confirm the diagnosis.

What are the available treatments for Chiari malformation?

The symptoms of Chiari malformation can be treated, but the disorder itself cannot yet be cured. Surgery is the most common treatment, specifically posterior fossa decompression to relieve pressure from the brain. A shunt insertion can also be used to drain excessive fluid from the skull and brain.