Xanthochromia in cerebrospinal fluid (CSF) indicates what condition?

Xanthochromia in cerebrospinal fluid (CSF) is characterized by a yellowish discoloration, which typically indicates the presence of bilirubin. This finding is most often associated with subarachnoid hemorrhage. In cases of subarachnoid hemorrhage, red blood cells that are released into the CSF break down over time, leading to the conversion of hemoglobin to bilirubin, which gives the CSF its yellow hue. This change can usually be detected several hours to days after a hemorrhagic event.

While multiple sclerosis, meningitis, and encephalitis involve changes in the CSF composition, they do not typically result in the xanthochromia that is seen in subarachnoid hemorrhage. For instance, in multiple sclerosis, the CSF may show oligoclonal bands, but not a yellow coloration. Meningitis—which can be viral, bacterial, or fungal—often leads to pleocytosis (increased white blood cells) and changes in glucose or protein levels, but does not cause the yellow discoloration seen in xanthochromia. Encephalitis may show similar changes to meningitis as well, but again, it does not lead to the specific finding of