Arnold-Chiari malformation
208893
226178303
2008-07-17T04:49:38Z
Arcadian
104523
/* History */ ref
{{Unreferenced|date=May 2008}}
{{Infobox_Disease
| Name = Arnold-Chiari
| Image = Chiari.jpg
| Caption = A T2-weighted sagittal MRI scan, from a patient with Chiari-like symptomatology, demonstrating tonsillar herniation less than 3 mm
| DiseasesDB = 899
| ICD10 = {{ICD10|Q|07|0|q|00}}
| ICD9 = {{ICD9|741.0}}
| ICDO =
| OMIM = 207950
| MedlinePlus =
| eMedicineSubj =
| eMedicineTopic =
| MeshID = D001139
}}
'''Arnold-Chiari malformation''', sometimes referred to as '''Chiari II malformation'''<ref name="urlDorlands Medical Dictionary:Chiari malformation">{{cite web |url=http://www.mercksource.com/pp/us/cns/cns_hl_dorlands_split.jsp?pg=/ppdocs/us/common/dorlands/dorland/nine/100011880.htm |title=Dorlands Medical Dictionary:Chiari malformation |format= |work= |accessdate=}}</ref> or '''ACM''', is a malformation of the [[brain]]. It consists of a downward displacement of the [[cerebellar tonsils]] and the [[medulla]]<ref name="url">{{cite web |url=http://www.urmc.rochester.edu/neuroslides/slide169.html |title=urmc.rochester.edu |format= |work= |accessdate=}}</ref> through the [[foramen magnum]], sometimes causing [[hydrocephalus]] as a result of obstruction of CSF outflow.<ref name="Bradley">{{cite book | last=Rosenbaum
| first=RB | coauthors=DP Ciaverella | title=Neurology in Clinical Practice | publisher=Butterworth Heinemann | date=2004 | pages=2192-2193 | isbn=0-7506-7469-5 }}</ref>
It occurs in many children born with both [[spina bifida]] and [[hydrocephalus]].
==Diagnosis==
The average age at diagnosis is about 24{{fact}} and it is more common in women.
Some characteristics are visible prenatally.<ref name="urlFetal MRI: Arnold-Chiari Malformation">{{cite web |url=http://www.bidmc.harvard.edu/content/bidmc/departments/radiology/files/fetalatlas/brain/chiari/chiari.html |title=Fetal MRI: Arnold-Chiari Malformation |format= |work= |accessdate=}}</ref>
==Incidence==
The [[incidence]] of Arnold-Chiari Malformation (Chiari I malformation) defined as tonsilar herniations of 3 to 5 mm or greater is approximately 1 in 1,200.{{fact}} The incidence of symptomatic Chiari is less but unknown.
A [[prevalence]] of approximately 1 in 1000 has been described.<ref name="urlArnold Chiari Malformation">{{cite web |url=http://www.uscneurosurgery.com/Disorders_includes/arnchiari.html |title=Arnold Chiari Malformation |format= |work= |accessdate=}}</ref>
==History and classification==
The Austrian pathologist Hans Chiari in the late 1800s 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.<ref name="urlArnold Chiari Malformation">{{cite web |url=http://neurosurgery.ucla.edu/body.cfm?id=109 |title=Arnold Chiari Malformation |format= |work= |accessdate=}}</ref>
* The most common form of Arnold-Chiari Malformation is Type I, which may be asymptomatic and discovered incidentally.
* Type II is usually accompanied by a [[myelomeningocele]]<ref name="urlNeuroradiology - Chiari malformation (I-IV)">{{cite web |url=http://www.mir.wustl.edu/neurorad/internal.asp?NavID=123 |title=Neuroradiology - Chiari malformation (I-IV) |format= |work= |accessdate=}}</ref> leading to partial or complete paralysis below the spinal defect.
* Type III causes severe neurological defects. It is associated with an [[encephalocele]].<ref name="Mesh">{{MeshName|Arnold-Chiari+Malformation}}</ref>
* Type IV involves a failure of brain development.<ref name="urlChiari Malformations - Department of Neurological Surgery">{{cite web |url=http://www.cumc.columbia.edu/dept/nsg/ct/chiari_malformation.html |title=Chiari Malformations - Department of Neurological Surgery |format= |work= |accessdate=}}</ref>
Other conditions sometimes associated with Chiari Malformation include [[hydrocephalus]],<ref name="urlNeuropathology For Medical Students">{{cite web |url=http://www.pathology.vcu.edu/WirSelfInst/neuro_medStudents/devdis.html |title=Neuropathology For Medical Students |format= |work= |accessdate=}}</ref> [[syringomyelia]], and [[spinal curvature]].
Some sources use "Chiari" to describe all four types, reserving the term "Arnold-Chiari" for type II only. Other sources use "Arnold-Chiari" for all four types.<ref name="urlCase Based Pediatrics Chapter">{{cite web |url=http://www.hawaii.edu/medicine/pediatrics/pedtext/s18c16.html |title=Case Based Pediatrics Chapter |format= |work= |accessdate=}}</ref>
==Symptoms==
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 [[Cerebrospinal Fluid|Cerebro-Spinal Fluid]] (CSF) flow may also cause a [[syrinx (medicine)|syrinx]] to form, eventually leading to [[syringomyelia]]. Chiari is often associated with major headaches, sometimes mistaken for migraines. Chiari headaches usually include intense throbbing in the back of the head. Chiari also includes extreme muscle soreness and low energy levels. It also can cause a hoarseness in the voice.
== Treatment ==
Once symptomatic onset occurs, a common treatment is decompression surgery,<ref name="pmid17786002">{{cite journal |author=Guo F, Wang M, Long J, ''et al'' |title=Surgical management of Chiari malformation: analysis of 128 cases |journal=Pediatr Neurosurg |volume=43 |issue=5 |pages=375–81 |year=2007 |pmid=17786002 |doi=10.1159/000106386 |url=http://content.karger.com/produktedb/produkte.asp?typ=fulltext&file=000106386}}</ref> in which a neurosurgeon usually removes the first and part of the second [[cervical vertebrae]] and part of the [[occipital bone]] of the [[skull]] to allow the flow of spinal fluid and may be accompanied by a shunt. This treatment is well recognized and accepted with many studies published (involving a total of hundreds of patients) in well-respected peer-reviewed medical journals showing that about 80% of patients obtain improvement.
A small number of neurological surgeons believe that detethering the spinal cord as an alternate approach relieves the compression of the brain against the skull opening (foramen magnum), obviating the need for decompression surgery and associated trauma. However, this approach is significantly less documented in the medical literature, with reports on only a handful of patients. It should be noted that the alternative spinal surgery is also not without risk.
== History ==
An [[Austria]]n [[pathologist]], [[Hans Chiari]], first described these hindbrain malformations in the 1890s.<ref>Chiari, H. Uber Veranderungen des Kleinhirns infolge von Hydrocephalie des Grosshirns. Dtsch. Med. Wochenschr. 17: 1172-1175, 1891.</ref> A colleague of Professor Chiari, Dr. Julius Arnold, later contributed to the definition of the condition,<ref>Arnold, J. Myelocyste, Transposition von Gewebskeimen und Sympodie. Beitr. Path. Anat. 16: 1-28, 1894.</ref> and students of Dr. Arnold (Schwalbe and Gredig)<ref name="isbn0-930405-26-9">{{cite book |author=Ashwal, Stephen |title=The Founders of child neurology |publisher=Norman Pub. in association with the Child Neurology Society |location=San Francisco |year=1990 |pages=195 |isbn=0-930405-26-9 |oclc= |doi= |accessdate=}}</ref> suggested the term "Arnold-Chiari malformation" to henceforth refer to the condition.<ref>{{WhoNamedIt|synd|1154|Arnold-Chiari malformation}}</ref><ref name="pmid16724811">{{cite journal |author=Bejjani GK |title=Definition of the adult Chiari malformation: a brief historical overview |journal=Neurosurg Focus |volume=11 |issue=1 |pages=E1 |year=2001 |pmid=16724811 |doi=10.3171/foc.2001.11.1.2 |url=http://thejns.org/doi/abs/10.3171/foc.2001.11.1.2?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dncbi.nlm.nih.gov}}</ref>
Some sources credit the characterization of the condition to [[John Cleland (anatomist)|Cleland]]<ref name="pmid2923030">{{cite journal |author=Susman J, Jones C, Wheatley D |title=Arnold-Chiari malformation: a diagnostic challenge |journal=Am Fam Physician |volume=39 |issue=3 |pages=207–11 |year=1989 |month=March |pmid=2923030 |doi= |url=http://findarticles.com/p/articles/mi_m3225/is_n3_v39/ai_7621931}}</ref><ref name="pmid17231474">{{cite journal |author=Cleland |title=Contribution to the Study of Spina Bifida, Encephalocele, and Anencephalus |journal=J Anat Physiol |volume=17 |issue=Pt 3 |pages=257–92 |year=1883 |month=April |pmid=17231474 |pmc=1310092 |doi= |url=}}</ref> or [[Jean Cruveilhier|Cruveilhier]].<ref name="pmid10601393">{{cite journal |author=Pearce JM |title=Arnold chiari, or "Cruveilhier cleland Chiari" malformation |journal=J. Neurol. Neurosurg. Psychiatr. |volume=68 |issue=1 |pages=13 |year=2000 |month=January |pmid=10601393 |doi= |url=http://jnnp.bmj.com/cgi/pmidlookup?view=long&pmid=10601393}}</ref>
== References ==
{{reflist|2}}
== External links ==
*[http://www.conquerchiari.org/ Conquer Chiari]
*[http://www.chiariconnectioninternational.com/ Chiari Connection International]
*[http://www.pressenter.com/~wacma/info.htm/ World Arnold Chiari Malformation Association]
*[http://www.asap.org/chiari-malformation.html American Syringomyelia Alliance Project]
*[http://www.theannconroytrust.org.uk/info.htm The Ann Conroy Trust] (ACT)
*[http://www.afacpa.org AFACPA] Association for Arnold Chiari Malformation Patients. In Spanish.
{{Congenital malformations and deformations of nervous system}}
[[Category:Neurological disorders]]
[[ca:Malformació d'Arnold-Chiari]]
[[de:Chiari-Malformation]]
[[es:Malformación de Arnold-Chiari]]
[[fr:Malformation d'Arnold-Chiari]]
[[it:Sindrome di Arnold-Chiari]]
[[ja:アーノルド・キアリ奇形]]
[[pl:Zespół Arnolda-Chiariego]]
[[fi:Arnold–Chiari-epämuodostuma]]