{{Infobox medical condition (new) | name = Xanthochromia | image = Xanthochromia.jpg | caption = | image_size = 130px | pronounce = | field = | synonyms = | symptoms = | complications = | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = | prevention = | treatment = | medication = | prognosis = | frequency = | deaths = }}
'''Xanthochromia''', from the Greek ''xanthos'' (ξανθός) "yellow" and ''chroma'' (χρώμα) "colour", is the yellowish appearance of [[cerebrospinal fluid]] that occurs several hours after bleeding into the subarachnoid space caused by certain medical conditions, most commonly [[subarachnoid hemorrhage]].<ref name=Cruickshank>{{Cite journal|last1=Cruickshank|first1=A|last2=Auld|first2=P.|last3=Beetham|first3=R.|title=Revised National Guidelines for Analysis of Cerebrospinal Fluid for Bilirubin in Suspected Subarachnoid Haemorrhage|journal=Annals of Clinical Biochemistry|volume=45|issue=Pt 3|pages=238–244|date=May 2008|pmid=18482910|doi=10.1258/acb.2008.007257|s2cid=24393459|display-authors=etal|doi-access=free}}</ref> Its presence can be determined by either [[spectrophotometry]] (measuring the absorption of particular wavelengths of [[light]]) or simple visual examination. It is unclear which method is superior.<ref>{{cite journal|last1=Chu|first1=K|last2=Hann|first2=A|last3=Greenslade|first3=J|last4=Williams|first4=J|last5=Brown|first5=A|title=Spectrophotometry or Visual Inspection to Most Reliably Detect Xanthochromia in Subarachnoid Hemorrhage: Systematic Review.|journal=Annals of Emergency Medicine|date=Mar 10, 2014|pmid=24635988|doi=10.1016/j.annemergmed.2014.01.023|volume=64|issue=3|pages=256–264.e5}}</ref>
==Physiology==
Cerebrospinal fluid, which fills the subarachnoid space between the [[arachnoid (brain)|arachnoid membrane]] and the [[pia mater]] surrounding the [[Human brain|brain]], is normally clear and colorless. When there has been bleeding into the subarachnoid space, the initial appearance of the cerebrospinal fluid can range from barely tinged with blood to frankly bloody, depending on the extent of bleeding. Within several hours, the red blood cells in the cerebrospinal fluid are destroyed, releasing their oxygen-carrying molecule [[heme]], which is then metabolized by [[enzyme]]s to [[bilirubin]], a yellow pigment. The most common cause for bleeding into the subarachnoid space is a subarachnoid hemorrhage from a ruptured [[cerebral aneurysm]].<ref name=vanGijn>{{cite journal|last1=van Gijn|first1=J.|last2=Kerr|first2=R.S.|last3=Rinkel|first3=G.J.|title=Subarachnoid Haemorrhage |journal=Lancet|volume=369|issue=9558|pages=306–318|year=2007|pmid=17258671|doi=10.1016/S0140-6736(07)60153-6|s2cid=29126514}}</ref>
The most frequently employed initial test for subarachnoid hemorrhage is a [[computed tomography]] scan of the head, but it detects only 98% of cases in the first 12 hours after the onset of symptoms, and becomes less useful afterwards.<ref>{{cite journal|last1=van der Wee|first1=N.|last2=Rinkel|first2=G.J.|last3=Hasan|first3=D.|last4=van Gijn J.|first4=J.|title=Detection of Subarachnoid Haemorrhage on Early CT: Is Lumbar Puncture Still Needed After a Negative Scan?|journal=Journal of Neurology, Neurosurgery, and Psychiatry|date=March 1995|volume=58|issue=3|pages=357–359|pmid=7897421|doi=10.1136/jnnp.58.3.357|pmc=1073376}}</ref> Therefore, a [[lumbar puncture]] ("spinal tap") is recommended to obtain cerebrospinal fluid if someone has symptoms of a subarachnoid hemorrhage (e.g., a [[thunderclap headache]], [[vomiting]], dizziness, new-onset [[seizure]]s, [[confusion]], a decreased level of consciousness or [[coma]], neck stiffness or other signs of [[meningismus]], and signs of sudden elevated [[intracranial pressure]]), but no blood is visible on the CT scan.<ref name=Cruickshank/> According to one article, a spinal tap is not necessary if no blood is seen on a CT scan done using a third generation scanner within six hours of the onset of the symptoms. However, this is not standard of care.<ref>{{Cite journal|last1=Perry|first1=J.J.|last2=Stiell|first2=I.G.|last3=Sivilotti|first3=M.L.|title=Sensitivity of Computed Tomography Performed Within Six Hours of Onset of Headache for Diagnosis of Subarachnoid Haemorrhage: Prospective Cohort Study|journal=British Medical Journal|volume=343|article-number=d4277|date=July 2011|doi=10.1136/bmj.d4277|pmid=21768192|pmc=3138338|display-authors=etal}}</ref><ref>{{cite journal|last1=Stewart|first1=H.|last2=Reuben|first2=A.|last3=McDonald|first3=J.|title=LP or not LP, That is the Question: Gold Standard or Unnecessary Procedure in Subarachnoid Haemorrhage?|journal=Emergency Medicine Journal|date=September 2014|volume=31|issue=9|pages=720–723|doi=10.1136/emermed-2013-202573|pmid=23756363|s2cid=206934433}}</ref>
Heme from red blood cells (RBC) that are in the cerebrospinal fluid because a blood vessel was damaged during the lumbar puncture (a "traumatic tap") has no time to be metabolized, and therefore no bilirubin is present.
After the cerebrospinal fluid is obtained, a variety of its parameters can be checked, including the presence of xanthochromia. If the cerebrospinal fluid is bloody, it is centrifuged to determine its color.
==Spectrophotometry==
Many laboratories rely on only the color of the cerebrospinal fluid to determine the presence or absence of xanthochromia.<ref name=Edlow>{{Cite web|last1=Edlow|first1=J.A.|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|access-date=2008-06-22|archive-date=2015-05-28|archive-url=https://web.archive.org/web/20150528140808/http://www.webmm.ahrq.gov/case.aspx?caseID=69}}</ref> However, recent guidelines suggest that [[spectrophotometry]] should be performed. Spectrophotometry relies on the different [[Beer–Lambert law|transmittance]], or conversely, [[absorption (electromagnetic radiation)|absorbance]], of [[light]] by different substances or materials, including solutes.<ref name=Williams>{{Cite journal |author= Williams, Anna|title=Xanthochromia in the cerebrospinal fluid|journal=Practical Neurology|volume=126|issue=4|date=2004|pages=174–175|url=http://pn.bmj.com/content/4/3/174.full.pdf}}</ref> Bilirubin absorbs light at wavelengths between 450 and 460 nm.<ref name=Petzold>{{cite journal|last1=Petzold|first1=Axel|last2=Keir|first2=Geoffrey|last3=Sharpe|first3=Lindsay T.|title=Spectrophotometry for Xanthochromia|journal=New England Journal of Medicine|year=2004|volume=351|issue=16|pages=1695–1696|doi=10.1056/nejm200410143511627|pmid=15483297|url=http://discovery.ucl.ac.uk/19077/|doi-access=free}}</ref> Spectrophotometry can also detect the presence of [[oxyhemoglobin]] and [[methemoglobin]], which absorb light at 410-418 nm and 403-410 nm, respectively, and also may indicate that bleeding has occurred; to identify substances in cerebrospinal fluid that absorb light at other wavelengths but are not due to bleeding, such as carotenoids;<ref name=Cruickshank/><ref name=Edlow/> and to detect very small amounts of yellow color saturation (about 0.62%) which may be missed by visual inspection, especially when the cerebrospinal fluid has been examined under incandescent lighting or a tungsten desk lamp (corresponding to [[International Commission on Illumination]] standard [[Standard illuminant#Illuminant A|illuminant A)]].<ref name=Williams/>
Visual inspection is the most frequent method used in the United States to assess cerebrospinal fluid for xanthochromia,<ref>{{cite journal|last1=Edlow|first1=J.A.|last2=Bruner|first2=K.S.|last3=Horowitz|first3=G.L.|title=Xanthochromia|journal=Archives of Pathology and Laboratory Medicine|date=April 2002|volume=126|issue=4|pages=413–415|pmid=11900563|doi=10.5858/2002-126-0413-X}}</ref> while spectrophotometry is used on up to 94% of specimens in the United Kingdom.<ref name=Cruickshank/><ref name=Petzold/> There is still disagreement about whether or not to routinely use spectrophotometry or whether visual inspection is adequate, and one group of authors has even advocated measuring bilirubin levels.<ref name=SpectrophotometryControversy>{{Cite journal|journal=Journal of the New Zealand Medical Association|title=CSF Bilirubin Measurement for Xanthochromia|last1=Florkowski|first1=Christopher|last2=Ungerer|first2=Jacobus|last3=Southby|first3=Sandi|last4=George|first4=Peter|volume=117|issue=1207|date=17 December 2004|pages=U1231|pmid=15608818|url=http://www.nzma.org.nz/__data/assets/pdf_file/0011/17948/Vol-117-No-1207-17-December-2004.pdf|access-date=21 May 2016|archive-date=8 May 2017|archive-url=https://web.archive.org/web/20170508153503/http://www.nzma.org.nz/__data/assets/pdf_file/0011/17948/Vol-117-No-1207-17-December-2004.pdf}}</ref>
==History== The concept was introduced in 1902 in a French report on a case of pneumococcal meningitis.<ref>{{cite journal |last1=Millian |first1=G |last2=Chiray |first2=F |title=Meningite a pneumocoques. Xanthochromie du liquide cephalo-rachidien. 1902; 4: 550-2. |journal=Bull Soc Anat Paris |date=1902 |issue=4 |pages=550-2}}</ref>
==See also== * [[Xanthochromism]]
==References== {{Reflist}}
{{Medical resources | DiseasesDB = 14197 | ICD10 = {{ICD10|R83.8}} | ICD9 = {{ICD9|792.0}} | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = }}
[[Category:Medical signs]]