Xanthochromia 5251873 221000505 2008-06-22T16:25:15Z Jfdwolff 46555 expanding - still need to get list of other causes from Edlow and get the history from Froin/Symonds {{Infobox_Disease | Name = {{PAGENAME}} | Image = | Caption = | DiseasesDB = 14197 | ICD10 = | ICD9 = | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = | }} '''Xanthochromia''' is the yellow appearance of [[cerebrospinal fluid]] (which envelops the [[brain]]) in particular medical conditions, especially [[subarachnoid hemorrhage]].<ref name=Cruickshank>{{cite journal |author=Cruickshank A, Auld P, Beetham R, ''et al'' |title=Revised national guidelines for analysis of cerebrospinal fluid for bilirubin in suspected subarachnoid haemorrhage |journal=Ann. Clin. Biochem. |volume=45 |issue=Pt 3 |pages=238–44 |year=2008 |month=May |pmid=18482910 |doi=10.1258/acb.2008.007257 |url=http://acb.rsmjournals.com/cgi/content/full/45/3/238}}</ref> The most effective test for SAH is [[computed tomography]] (CT, a type of brain scan), but this identifies only 98% of cases in the first 12 hours after the symptoms and becomes less useful afterwards. Therefore, obtaining cerebrospinal fluid by [[lumbar puncture]] is recommended if someone has characteristic symptoms (e.g. a [[thunderclap headache]]) but no blood visible on the CT scan.<ref name=Cruickshank/> The yellow appearance is due to the fact that [[red blood cell]]s entering the CSF during the bleeding are eventually destroyed by the body, and its oxygen carrying chemical [[heme]] is degraded by [[enzyme]]s into the yellow-green pigment [[bilirubin]]. Heme from red blood cells that enter the CSF for a different reason, e.g. because a small blood vessel was damaged during the lumbar puncture, has no time to be digested in this fashion, and bilirubin is absent. Many laboratories rely on the color of the fluid alone when reporting the presence or absence of xanthochromia.<ref name=Edlow>{{cite web |author=Edlow JV | url=http://www.webmm.ahrq.gov/case.aspx?caseID=69 |title=The Worst Headache |publisher=Agency for Healthcare Research and Quality |work=Morbidity & Mortality Rounds on the Web |date=July 2004| accessdate=2008-06-22}}</ref> Recent guidelines, however, suggest that [[spectrophotometry]] should be performed. This relies on the fact that bilirubin absorbs light of wavelengths between 450–460 nm. Two related substances that are also released when heme is metabolized are [[oxyhemoglobin]] and [[methemoglobin]] (the absorption ranges are 410-418 nm and 403-410 nm respectively) may also be detected during this process.<ref name=Cruickshank/> There are other causes for xanthochromia.<ref name=Edlow/> ==References== {{reflist}} {{med-stub}} {{color-stub}}