Posturing can be caused by conditions that lead to large increases in [[intracranial pressure]].<ref name="Yamamoto">Yamamoto, Loren G. 1996. [http://www.hawaii.edu/medicine/pediatrics/pemxray/v5c06.html “Intracranial Hypertension and Brain Herniation Syndromes: Radiology Cases in Pediatric Emergency Medicine"]. '''5'''(6). Kapiolani Medical Center for Women and Children; University of Hawaii; John A. Burns School of Medicine. Retrieved January 24, 2007.</ref> Such conditions include [[traumatic brain injury]], [[stroke]], [[intracranial hemorrhage]], [[brain tumor]]s, and [[encephalopathy]].<ref name="adam">ADAM. 2005. [http://adam.about.com/encyclopedia/003300.htm "Decorticate Posture"]. Retrieved January 15, 2007.</ref> Posturing due to stroke usually only occurs on one side of the body and may also be referred to as [[spastic hemiplegia]].<ref name="wrong"/> Diseases such as [[Malaria]] are also known to cause the brain to swell and cause this posturing effect.
Decerebrate and decorticate posturing can indicate that [[brain herniation]] is occurring<ref name="Ayling ">{{cite journal | last =Ayling | first = J| authorlink = | coauthors = | title =Managing head injuries | journal =Emergency Medical Services | volume =31 | issue = 8| pages =42 | publisher = | date =2002 | url = | doi = | id =PMID 12224233 | accessdate =2007-01-23 }} </ref> or is about to occur.<ref name="Yamamoto"/> Brain herniation is an extremely dangerous condition in which parts of the brain are pushed past hard structures within the skull. In herniation syndrome, which is indicative of brain herniation, decorticate posturing occurs, and, if the condition is left untreated, develops into decerebrate posturing.<ref name="Ayling "/>
Posturing has also been displayed by patients with [[Creutzfeldt-Jakob disease]].<ref name="Obi ">{{cite journal | last =Obi | first =T | authorlink = | coauthors =Takatsu M, Kitamoto T, Mizoguchi K, Nishimura Y | title =A case of Creutzfeldt-Jakob disease (CJD) started with monoparesis of the left arm | journal =Rinsho Shinkeigaku (Clinical Neurology) | volume =36 | issue =11 | pages =1245-1248 | publisher = | date =1996 | url = | doi = | id =PMID 9046857 | accessdate =2007-01-24 }} </ref>
Decerebrate posturing can occur with diffuse cerebral [[hypoxia]].<ref name="pmid15094576">{{cite journal |author=De Rosa G, Delogu AB, Piastra M, Chiaretti A, Bloise R, Priori SG |title=Catecholaminergic polymorphic ventricular tachycardia: successful emergency treatment with intravenous propranolol |journal=Pediatric emergency care |volume=20 |issue=3 |pages=175-7 |year=2004 |pmid=15094576 |doi=}}</ref>
[[Brain abscess]]es may also cause decorticate posturing.<ref name="wrong"/>
===In Children===
In children younger than age 2, posturing is not a reliable finding because their nervous systems are not yet developed.<ref name="wrong"/> However, [[Reye's syndrome]] and traumatic brain injury can both cause decorticate posturing in children.<ref name="wrong"/>
For reasons that are poorly understood, but which may be related to high intracranial pressure, children with [[malaria]] frequently exhibit decorticate, decerebrate, and opisthotonic posturing.<ref name="Idro ">{{cite journal | last =Idro | first =R | authorlink = | coauthors =Otieno G, White S, Kahindi A, Fegan G, Ogutu B, Mithwani S, Maitland K, Neville BG, Newton CR | title = Decorticate, decerebrate and opisthotonic posturing and seizures in Kenyan children with cerebral malaria| journal =Malaria Journal | volume =4 | issue =57 | pages = | publisher = | date = | url =http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=16336645 | doi = | id =PMID 16336645 | accessdate =2007-01-21 }} </ref>
==Decorticate posturing==
==Decorticate posturing==
Revision as of 20:29, 18 January 2013
Abnormal posturing
Decorticate posturing, with elbows, wrists and fingers flexed, and legs extended and rotated inward.
Decorticate posturing is also called decorticate response, decorticate rigidity, flexor posturing, or "mummy baby". Patients with decorticate posturing present with the arms flexed, or bent inward on the chest, the hands are clenched into fists, and the legs extended. Decorticate posturing indicates damage to the mesencephalic region, or the corticospinal tract, along which impulses travel from the brain to the spinal cord.[1]
There are two parts to decorticate posturing. The first is the disinhibition of the red nucleus with facilitation of the rubrospinal tract. The rubrospinal tract facilitates motor neurons in the cervical spinal cord subserving flexor muscles of the upper extremities. The second component of decorticate posturing is the disinhibition of the lateral vestibulospinal tract which facilitates motor neurons in the lower cord subserving extensor muscles of the lower extremities. The disinhibition of these two tracts by lesions above the red nucleus is what leads to the characteristic flexion posturing of the upper extremities and extensor posturing of the lower extremities. While an ominous sign of severe brain damage, the damage of which decorticate posturing is indicative is not as serious as that indicated by decerebrate posturing.
Decerebrate posturing
Decerebrate posturing is also called decerebrate response, decerebrate rigidity, or extensor posturing. In decerebrate posturing, the head is arched back, the arms are extended by the sides, and the legs are extended. [2] Decerebrate posturing indicates brain stem damage or rather damage below the level of the red nucleus (eg. mid-collicular lesion). A patient with decorticate posturing may begin to show decerebrate posturing, or may go from one form of posturing to the other;[1] progression from decorticate posturing to decerebrate posturing is often indicative of uncal (transtentorial) or tonsilar brain herniation. Posturing may occur on one or the other side of the body, or it may occur on both sides.[1] Activation of gamma motor neurons is thought to be important in decerebrate rigidity due to studies in animals showing that dorsal root transection eliminates decerebrate rigidity symptoms.[3]
