Chiari malformation: Difference between revisions

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A '''Chiari malformation''' is a structural defect in the cerebellum, the part of the brain that controls balance. It involves the lower part of the cerebellum, known as the cerebellar tonsils, extending into the foramen magnum, the opening at the base of the skull through which the spinal cord passes.
{{Infobox medical condition
[[File:Sagittal MRI scan of brain of patient with Chiari malformation.jpg|thumb|Sagittal MRI scan of brain of patient with Chiari malformation]]
| name = Chiari Malformation
== Classification ==
| image = MRI of human brain with type-1 Arnold-Chiari malformation and herniated cerebellum.jpg
*Chiari malformations are classified into four types:
| caption = MRI showing Type I Chiari Malformation
*'''Chiari I''' is the most common type and is often asymptomatic. Symptoms, if they occur, generally appear during adolescence or adulthood. This type involves herniation of the cerebellar tonsils into the foramen magnum.
| field = [[Neurology]]
*'''Chiari II''', also known as Arnold-Chiari malformation, is associated with myelomeningocele, a form of spina bifida. Both cerebellar and brain stem tissue extend into the foramen magnum in Chiari II.
| symptoms = Headache, neck pain, balance problems, muscle weakness
*'''Chiari III''' is a rare and severe malformation involving herniation of the cerebellum and brain stem into a spina bifida defect in the neck or upper back.
| complications = Syringomyelia, hydrocephalus
*'''Chiari IV''' involves an incomplete or underdeveloped cerebellum—a condition known as cerebellar hypoplasia. It's extremely rare and associated with poor outcomes.
| onset = Congenital
| types = Type I, Type II, Type III, Type IV
| causes = Structural defects in the brain and spinal cord during fetal development
| diagnosis = [[MRI]]
| treatment = Monitoring, surgery
}}


== Symptoms ==
'''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.
Symptoms vary widely and depend on the type of Chiari malformation. Symptoms may include headaches, particularly after sudden coughing, sneezing or straining, problems with balance and coordination, dizziness, dysphagia, vision problems, and numbness or weakness in the limbs.


== Diagnosis ==
==Types==
Diagnosis is usually made by magnetic resonance imaging (MRI) which can visualize the structures of the brain, spinal cord, and the position of cerebellar tonsils relative to the foramen magnum.
Chiari malformations are classified into four types:


== Treatment ==
* '''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.
Treatment depends on the severity of the symptoms. Asymptomatic individuals usually require no treatment. Symptomatic cases are treated surgically, with a procedure known as a posterior fossa decompression, which creates more space for the cerebellum and relieves pressure on the spinal cord.


== References ==
* '''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.
<references>
 
*Meadows, J., Kraut, M., Guarnieri, M., Haroun, R. I., & Carson, B. S. (2000). Asymptomatic Chiari Type I malformations identified on magnetic resonance imaging. Journal of *Neurosurgery, 92(6), 920-926.
* '''Type III''': A rare and severe form where the cerebellum and brainstem herniate through the foramen magnum and into the spinal canal.
*Batzdorf, U. (1995). Chiari I malformation with syringomyelia. Evaluation of surgical therapy by magnetic resonance imaging. Journal of Neurosurgery, 82(5), 799-805.
 
*Noudel, R., Jovenin, N., Eap, C., Scherpereel, B., Pierot, L., Rousseaux, P., ... & Brotchi, J. (2008). Incidence of basilar invagination in Chiari malformation type I: comparative *morphometric study of 364 symptomatic patients with Chiari malformation type I. Journal of Neurosurgery: Spine, 9(5), 461-467.
* '''Type IV''': Involves an underdeveloped or missing cerebellum and is the most severe form.
</references>
 
{{stub}}
==Symptoms==
[[Category: Neurological Disorders]]
Symptoms of Chiari malformation can vary depending on the type and severity. Common symptoms include:
[[Category: Neurosurgery]]
 
[[Category: Pediatrics]]
* Headaches, often severe and worsened by coughing, sneezing, or straining
[[Category: Rare diseases]]
* 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. [[File:Neck MRI 130850-dichromatic t1-t2-t2.png|thumb|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."
 
{{Neuroscience}}
{{Congenital disorders}}
 
[[Category:Neurological disorders]]
[[Category:Congenital disorders]]

Latest revision as of 02:47, 11 December 2024

Chiari Malformation
MRI of human brain with type-1 Arnold-Chiari malformation and herniated cerebellum.jpg
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[edit]

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[edit]

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[edit]

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[edit]

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[edit]

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[edit]

References[edit]

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


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