Arnold-Chiari malformation: Difference between revisions

Jump to navigation Jump to search
Line 106: Line 106:
*Impaired [[gag reflex]]
*Impaired [[gag reflex]]
*Impaired [[coordination]]
*Impaired [[coordination]]
===X ray skull===
===Imaging Findings===
====X ray skull====
May demonstrate associated abnormalities of the skull base.
May demonstrate associated abnormalities of the skull base.
===CT===
===CT===
May demonstrate hydrocephalus, herniated cerebellar tonsils, and a flattened spinal cord. Rarely will CT show a syrinx.
May demonstrate hydrocephalus, herniated cerebellar tonsils, and a flattened spinal cord. Rarely will CT show a syrinx.

Revision as of 19:06, 25 July 2012

Arnold-Chiari malformation
An uncollapsed syrinx (before surgery).
ICD-10 Q07.0
ICD-9 741.0
OMIM 207950
DiseasesDB 899
MeSH D001139

WikiDoc Resources for Arnold-Chiari malformation

Articles

Most recent articles on Arnold-Chiari malformation

Most cited articles on Arnold-Chiari malformation

Review articles on Arnold-Chiari malformation

Articles on Arnold-Chiari malformation in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Arnold-Chiari malformation

Images of Arnold-Chiari malformation

Photos of Arnold-Chiari malformation

Podcasts & MP3s on Arnold-Chiari malformation

Videos on Arnold-Chiari malformation

Evidence Based Medicine

Cochrane Collaboration on Arnold-Chiari malformation

Bandolier on Arnold-Chiari malformation

TRIP on Arnold-Chiari malformation

Clinical Trials

Ongoing Trials on Arnold-Chiari malformation at Clinical Trials.gov

Trial results on Arnold-Chiari malformation

Clinical Trials on Arnold-Chiari malformation at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Arnold-Chiari malformation

NICE Guidance on Arnold-Chiari malformation

NHS PRODIGY Guidance

FDA on Arnold-Chiari malformation

CDC on Arnold-Chiari malformation

Books

Books on Arnold-Chiari malformation

News

Arnold-Chiari malformation in the news

Be alerted to news on Arnold-Chiari malformation

News trends on Arnold-Chiari malformation

Commentary

Blogs on Arnold-Chiari malformation

Definitions

Definitions of Arnold-Chiari malformation

Patient Resources / Community

Patient resources on Arnold-Chiari malformation

Discussion groups on Arnold-Chiari malformation

Patient Handouts on Arnold-Chiari malformation

Directions to Hospitals Treating Arnold-Chiari malformation

Risk calculators and risk factors for Arnold-Chiari malformation

Healthcare Provider Resources

Symptoms of Arnold-Chiari malformation

Causes & Risk Factors for Arnold-Chiari malformation

Diagnostic studies for Arnold-Chiari malformation

Treatment of Arnold-Chiari malformation

Continuing Medical Education (CME)

CME Programs on Arnold-Chiari malformation

International

Arnold-Chiari malformation en Espanol

Arnold-Chiari malformation en Francais

Business

Arnold-Chiari malformation in the Marketplace

Patents on Arnold-Chiari malformation

Experimental / Informatics

List of terms related to Arnold-Chiari malformation

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Arnold-Chiari malformation, sometimes referred to as Chiari malformation or ACM, is a congenital anomaly of the brain.

Arnold-Chiari Malformation II occurs in almost all children born with both spina bifida and hydrocephalus, but ACM I is typically seen in children and adults without spina bifida. The scale of severity is rated I - IV, with IV being the most severe. [1] [2] [3]

Classification

The Austrian pathologist Hans Chiari in the late 19th century described seemingly related anomalies of the hindbrain, the so called Chiari malformations I, II and III. Later, other investigators added a fourth (Chiari IV) malformation. The scale of severity is rated I - IV, with IV being the most severe. Types III and IV are very rare.[4]

Type Presentation Other notes
I A congenital malformation. Is generally asymptomatic during childhood, but often manifests with headaches and cerebellar symptoms. Herniation of cerebellar tonsils.[5][6] The most common form.
Syndrome of occipitoatlantoaxial hypermobility An acquired Chiari I Malformation in patients with hereditary disorders of connective tissue.[7] Patients who exhibit extreme joint hypermobility and connective tissue weakness as a result of Ehlers-Danlos syndrome or Marfan Syndrome are susceptible to instabilities of the craniocervical junction and thus acquiring a Chiari Malformation. This type is difficult to diagnose and treat.[8]
II Usually accompanied by a lumbar myelomeningocele[9] leading to partial or complete paralysis below the spinal defect. As opposed to the less pronounced tonsillar herniation seen with Chiari I, there is a larger cerebellar vermian displacement. Low lying torcular herophili, tectal beaking, and hydrocephalus with consequent clival hypoplasia are classic anatomic associations.[10] The position of the torcular herophili is important for distinction from Dandy-Walker syndrome in which it is classically upturned. This is important because the hypoplastic cerebellum of Dandy-Walker may be difficult to distinguish from a Chiari malformation that has herniated or is ectopic on imaging. Colpocephaly may be seen due to the associated neural tube defect.
III Causes severe neurological defects. It is associated with an occipital encephalocele.[11]
IV Characterized by a lack of cerebellar development.[12]
File:Neck MRI 130850-dichromatic t1-t2-t2.png
Syringomiyelia associated with Chiari malformation

Other conditions sometimes associated with Chiari Malformation include hydrocephalus,[13] syringomyelia, spinal curvature, tethered spinal cord syndrome, and connective tissue disorders[7] such as Ehlers-Danlos syndrome and Marfan Syndrome.

Pathophysiology

  • The most widely accepted pathophysiological mechanism by which Chiari Type 1 Malformations occur is by a reduction or lack of development of the posterior fossa as a result of either congenital or acquired disorders.
  • The cerebellar tonsils are elongated and pushed down through the opening of the base of the skull (see foramen magnum), blocking the flow of cerebrospinal fluid (CSF).
  • The brainstem, cranial nerves, and the lower portion of the cerebellum may be stretched or compressed.
  • Therefore, any of the functions controlled by these areas may be affected. The blockage of CSF flow may also cause a syrinx to form, eventually leading to syringomyelia. Many sufferers turn to the Chiari Institute in Long Island, NY for specialized medical attention and medication.

Causes

Congenital causes are

Acquired disorders include space occupying lesions due to one of several potential causes ranging from brain tumors to hematomas.[14]

Historical Perspective

An Austrian pathologist, Hans Chiari, first described these hindbrain malformations in the 1890s. A colleague of Professor Chiari, Dr. Julius Arnold later contributed to the definition of the condition, and students of Dr. Arnold suggested the term "Arnold-Chiari malformation" to henceforth refer to the condition.[15]

Diagnosis

Symptoms

In infants, the most common symptoms are

In older children

  • Upper (and lower as age marches on) limb weakness
  • Breathing difficulties may occur
  • Patients may experience no symptoms or remain asymptomatic until early adulthood at which point they will often experience severe headaches and neck pain
  • Fatigue
  • Dizziness
  • Vertigo
  • Neuropathic pain
  • Pain at the point of tethering
  • Visual disturbances
  • Difficulty swallowing
  • Ringing in the ears
  • Sleep apnea
  • Impaired fine motor skills
  • Muscle weakness
  • Palpitations
  • Excessive clearing of the throat with no obstructions
  • Because of the complex combination of symptoms and the lack of experience with ACM1 had by many, even outstanding neurologists and neurosurgeons, many patients are frequently misdiagnosed.
  • Some patients may go an entire lifetime without having noticeable symptoms. Or, symptoms can be minimal, then turn severe suddenly due to head trauma which alters the condition of the spine, brain, or cerebellar tonsils and begins to cause more difficulties...

physical Examination

Vitals

Pulse

Rate

Tachycardia may be present.

Eye

Neurologic

Imaging Findings

X ray skull

May demonstrate associated abnormalities of the skull base.

CT

May demonstrate hydrocephalus, herniated cerebellar tonsils, and a flattened spinal cord. Rarely will CT show a syrinx.

MRI

MRI is the imaging modality of choice to evaluate for a Chiari I malformation. MRI findings:

  • Tonsillar displacement is measured from the basion-opisthion line on a sigittal image.
  • Herniation is usually at least 5mm, though patients with 3-5mm herniation may also have the malformation.
  • MRI CSF flow studies may prove to be helpful and are currently under investigation.

Patient #1

Images shown below are courtesy of RadsWiki and copylefted

Patient #2

Images shown below are courtesy of RadsWiki and copylefted


Other Radiologic Findings









Pathological Findings












Treatment

Surgery

Once these "onset of symptoms" occurs, the most frequent treatment is decompression surgery, in which a neurosurgeon seeks to open the base of the skull and through various methods unrestrict CSF flow to the spine.

This treatment is under observation and review. Decompression is a very taxing surgical procedure and is now, in some circles, disdained in lieu of tethered cord detachment at the base of the spine. Some neurological surgeons find that detethering the spinal cord relieves the compression of the brain against the skull opening (foramen magnum) obviating the need for decompression surgery and associated trauma. It should be noted that the alternative spinal surgery is not without risk.

References

  1. Barkovich AJ, Wippold FJ, Sherman JL, Citrin CM. Significance of cerebellar tonsillar position on MR. AJNR Am J Neuroradiol. 1986 Sep-Oct;7(5):795-9.
  2. Haughton VM, Korosec FR, Medow JE, Dolar MT, Iskandar BJ. Peak systolic and diastolic CSF velocity in the foramen magnum in adult patients with Chiari I malformations and in normal control participants. AJNR Am J Neuroradiol. 2003 Feb;24(2):169-76.
  3. Elster A, Chen M. Chiari I malformations: clinical and radiologic reappraisal. Radiology. 1992; 183:347-353.
  4. "Arnold Chiari Malformation".
  5. Kojima A, Mayanagi K, Okui S (2009). "Progression of pre-existing Chiari type I malformation secondary to cerebellar hemorrhage: case report". Neurol. Med. Chir. (Tokyo). 49 (2): 90–2. doi:10.2176/nmc.49.90. PMID 19246872. Unknown parameter |month= ignored (help)[dead link]
  6. O'Shaughnessy BA, Bendok BR, Parkinson RJ; et al. (2006). "Acquired Chiari malformation Type I associated with a supratentorial arteriovenous malformation. Case report and review of the literature". J. Neurosurg. 104 (1 Suppl): 28–32. doi:10.3171/ped.2006.104.1.28. PMID 16509477. Unknown parameter |month= ignored (help)
  7. 7.0 7.1 Milhorat TH, Bolognese PA, Nishikawa M, McDonnell NB, Francomano CA (2007). "Syndrome of occipitoatlantoaxial hypermobility, cranial settling, and chiari malformation type I in patients with hereditary disorders of connective tissue". Journal of Neurosurgery: Spine. 7 (6): 601–9. doi:10.3171/SPI-07/12/601. PMID 18074684. Unknown parameter |month= ignored (help)
  8. "Dr. Bland Discusses Chiari & EDS 4(10)". Conquerchiari.org. 2006-11-20. Retrieved 2011-11-04.
  9. "Neuroradiology - Chiari malformation (I-IV)".
  10. "Cleveland Clinic Children's Hospital Pediatric Radiology Image Gallery". Cleveland Clinic. 2010. Archived from the original on 27 June 2010. Retrieved June 14, 2010.
  11. Arnold-Chiari+Malformation at the US National Library of Medicine Medical Subject Headings (MeSH)
  12. "Chiari Malformations - Department of Neurological Surgery".
  13. "Neuropathology For Medical Students".
  14. Loukas M, Shayota BJ, Oelhafen K, Miller JH, Chern JJ, Tubbs RS, Oakes WJ (2011). "Associated disorders of Chiari Type I malformations: a review". Neurosurg Focus. 31 (3): E3. doi:10.3171/2011.6.FOCUS11112. PMID 21882908.
  15. Template:WhoNamedIt

Template:Congenital malformations and deformations of nervous system ca:Malformació d'Arnold-Chiari de:Chiari-Malformation it:Sindrome di Arnold-Chiari

Template:WikiDoc Sources