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Brain & Nervous System Health Center

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Chiari Malformation

Types of Chiari Malformations continued...

Type III. This is the most serious form of Chiari malformation. It involves the protrusion or herniation of the cerebellum and brain stem through the foramen magnum and into the spinal cord. This usually causes severe neurological defects. Type III is a rare type.

Type IV. This involves an incomplete or undeveloped cerebellum. It sometimes is associated with exposed parts of the skull and spinal cord. Type IV is a rare type.

In addition to spina bifida, other conditions sometimes associated with Chiari malformations include:

Hydrocephalus. An excessive buildup of cerebrospinal fluid in the brain.

Syringomyelia. A disorder in which a cyst develops in the spinal cord's central canal.

Tethered cord syndrome. A progressive disorder in which the spinal cord attaches itself to the bony spine.

Spinal curvature. This includes conditions such as:

Symptoms of Chiari Malformations

Chiari malformation is associated with a wide range of symptoms which vary by type.

Type I Chiari malformation usually causes no symptoms. Most people with the condition don't even know that they have it unless it is incidentally discovered during a diagnostic imaging test.

But if the malformation is severe, type I may cause symptoms such as:

  • Pain in the lower back of the head into the neck; it usually develops quickly and intensifies with any activity that increases pressure in the brain, such as coughing and sneezing.
  • Dizziness and problems with balance and coordination
  • Swallowing difficulties
  • Sleep apnea

Most children born with type II Chiari malformation have hydrocephalus. Older children with type II Chiari malformation may develop head pain associated with:

Some of the most common symptoms are linked to problems with the function of nerves in the brain stem. These include:

  • weakness of vocal cords
  • swallowing difficulties
  • breathing irregularities
  • serious changes in the function of nerves in the throat and tongue

Treatment of Chiari Malformations

If a Chiari malformation is suspected, a doctor will perform a physical exam. The doctor will also check functions controlled by the cerebellum and spinal cord. These functions include:

  • balance
  • touch
  • reflexes
  • sensation
  • motor skills

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