Chiari Malformation

Chiari malformation is a congenital (present at birth) defect occurring in the back of the head where the brain and spinal cord connect. There are four types of Chiari malformations:

Type 1
occurs when the base of the skull and upper spinal area do not form properly, a type 1 Chiari malformation commonly goes unnoticed until problems arise in the adolescent or adult years of life. The headaches most typical of Chiari I malformations are usually located at the back of the head, and are often made worse by exertion.

Type 2
is the most common and is caused by part of the back of the brain shifting downward through the bottom of the skull. Type 2 Chiari malformations are typically seen in infants who are born with spina bifida, a neurological condition that causes a portion of the spinal cord and the surrounding structures to develop outside, instead of inside, the body. Type 2 Chiari malformations can also be associated with hydrocephalus, a condition in which there is an overproduction or lack of absorption of the cerebral spinal fluid (CSF) that is found inside of the ventricles (fluid-filled areas) inside of the brain. The increased fluid causes the pressure inside of the head to increase and the skull bones to expand to a larger-than-normal appearance.

Type 3
Chiari malformations occur when the back of the brain protrudes out of an opening in the back of the skull area.

Type 4
Chiari malformations occur when the back of the brain fails to develop normally.


Signs and symptoms of pressure from a pituitary tumor may include:

  • Headaches
  • 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)
  • Speech problems, such as hoarseness
  • Changes in breathing pattern
  • Swallowing problems, such as gagging
  • Quick downward eye movements
  • Weakness in arms


In addition to a complete medical history and physical examination, a patient might undergo a series of diagnostic procedures including Magnetic resonance imaging (MRI) and CT scans.


Some CMs are asymptomatic and do not interfere with a person’s activities of daily living. In other cases, medications may ease certain symptoms, such as pain.

Surgery is the only treatment available to correct functional disturbances or halt the progression of damage to the central nervous system. Most individuals who have surgery see a reduction in their symptoms and/or prolonged periods of relative stability. Surgeries may include decompression surgery and spinal laminectomy.