Chiari malformation

Not to be confused with Budd–Chiari syndrome.

Chiari malformation
Other namesHindbrain herniation
A sagittal FLAIR MRI scan, from a patient with an Arnold–Chiari malformation, demonstrating tonsillar herniation of 7 mm.
Pronunciation
SpecialtyNeurosurgery
ComplicationsHydrocephalus, spina bifida, syringomyelia, tethered cord syndrome.[3]
TypesI, II, III, IV[4]
TreatmentDecompressive surgery[5]
Prognosisvaries by type-see below
Frequency1 in 100 (type I)[a]
Named after

In neurology, the Chiari malformation (/kiˈɑːri/ kee-AR-ee; CM) is a structural defect in the cerebellum, characterized by a downward displacement of one or both cerebellar tonsils through the foramen magnum (the opening at the base of the skull).

CMs can cause headaches, difficulty swallowing, vomiting, dizziness, neck pain, unsteady gait, poor hand coordination, numbness and tingling of the hands and feet, and speech problems.[7] Less often, people may experience ringing or buzzing in the ears, weakness, slow heart rhythm, or fast heart rhythm, curvature of the spine (scoliosis) related to spinal cord impairment, abnormal breathing, such as central sleep apnea, characterized by periods of breathing cessation during sleep, and, in severe cases, paralysis.[7] CM can sometimes lead to non-communicating hydrocephalus[8] as a result of obstruction of cerebrospinal fluid (CSF) outflow.[9] The CSF outflow is caused by phase difference in outflow and influx of blood in the vasculature of the brain.

The malformation is named after the Austrian pathologist Hans Chiari. A type II CM is also known as an Arnold–Chiari malformation in honor of Chiari and German pathologist Julius Arnold.

  1. ^ "Chiari malformation". Cambridge Dictionary. Cambridge University Press.
  2. ^ "Chiari malformation". Merriam-Webster.com Dictionary. Merriam-Webster.
  3. ^ clinic, mayo. "Chiari malformation". mayoclinic.org. Mayo Clinic. Retrieved June 19, 2022.
  4. ^ Cite error: The named reference Types of Chiari was invoked but never defined (see the help page).
  5. ^ Guo F, Wang M, Long J, Wang H, Sun H, Yang B, Song L (2007). "Surgical management of Chiari malformation: analysis of 128 cases". Pediatric Neurosurgery. 43 (5): 375–81. doi:10.1159/000106386. PMID 17786002. S2CID 29634884.
  6. ^ Sadler, Brooke; Kuensting, Timothy; Strahle, Jennifer; Park, Tae Sung; Smyth, Matthew; Limbrick, David D.; Dobbs, Matthew B.; Haller, Gabe; Gurnett, Christina A. (May 1, 2020). "Prevalence and Impact of Underlying Diagnosis and Comorbidities on Chiari 1 Malformation". Pediatric Neurology. 106: 32–37. doi:10.1016/j.pediatrneurol.2019.12.005. ISSN 0887-8994. PMC 7156318. PMID 32113729.
  7. ^ a b "Chiari malformation: Symptoms". Mayo Clinic. November 13, 2008. Archived from the original on February 11, 2010.
  8. ^ Hydrocephalus at eMedicine
  9. ^ Rosenbaum, RB; DP Ciaverella (2004). Neurology in Clinical Practice. Butterworth Heinemann. pp. 2192–2193. ISBN 978-0-7506-7469-0.


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