Chiari malformation

Chiari Malformation
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Headache, neck pain, balance problems, muscle weakness
Complications	Syringomyelia, hydrocephalus
Onset	Congenital
Duration	N/A
Types	Type I, Type II, Type III, Type IV
Causes	Structural defects in the brain and spinal cord during fetal development
Risks	N/A
Diagnosis	MRI
Differential diagnosis	N/A
Prevention	N/A
Treatment	Monitoring, surgery
Medication	N/A
Prognosis	N/A
Frequency	N/A
Deaths	N/A

Chiari malformation is a condition in which brain tissue 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. Chiari malformation is named after Hans Chiari, an Austrian pathologist who first described the condition in the late 19th century.

Types

Chiari malformations are classified into four types:

• Type I: The most common form, where the lower part of the cerebellum (called the cerebellar tonsils) extends into the foramen magnum, the opening at the base of the skull. This type is often asymptomatic and may be discovered incidentally during an MRI for another condition.

• Type II: Also known as Arnold-Chiari malformation, this type is usually associated with a form of spina bifida called myelomeningocele, where the spinal canal and backbone do not close before birth.

• Type III: A rare and severe form where the cerebellum and brainstem herniate through the foramen magnum and into the spinal canal.

• Type IV: Involves an underdeveloped or missing cerebellum and is the most severe form.

Symptoms

Symptoms of Chiari malformation can vary depending on the type and severity. Common symptoms include:

• Headaches, often severe and worsened by coughing, sneezing, or straining
• Neck pain
• Balance problems
• Muscle weakness or numbness
• Difficulty swallowing
• Dizziness
• Vision problems

Diagnosis

Chiari malformation is typically diagnosed using magnetic resonance imaging (MRI), which provides detailed images of the brain and spinal cord.

MRI of the neck showing Chiari malformation

Treatment

Treatment for Chiari malformation depends on the severity and symptoms. Options include:

• Monitoring: For asymptomatic cases, regular monitoring with MRI may be sufficient.
• Surgery: The most common treatment for symptomatic Chiari malformation is decompression surgery, which involves removing a small section of bone at the back of the skull to relieve pressure on the brain.

Complications

Chiari malformation can lead to complications such as:

• Syringomyelia: A condition where a cyst forms within the spinal cord.
• Hydrocephalus: An accumulation of fluid in the brain.

Also see

• Syringomyelia
• Hydrocephalus
• Spina bifida
• Foramen magnum

References

• National Institute of Neurological Disorders and Stroke. "Chiari Malformation Fact Sheet."
• Mayo Clinic. "Chiari Malformation."