In cerebrospinal fluid analysis, which option describes xanthochromia?

• A. A sign of bacterial meningitis.
• B. Yellow discoloration indicating prior subarachnoid hemorrhage or RBC breakdown.
• C. Increased protein content.
• D. Normal CSF.

Answer: (B)

Xanthochromia is the yellow discoloration of cerebrospinal fluid caused by the breakdown of red blood cells in the subarachnoid space, with bilirubin formation giving the color. This finding specifically points to prior bleeding into the CSF, most classically a subarachnoid hemorrhage, rather than a simple inflammatory or normal state. While bacterial meningitis changes CSF chemistry and cells, it does not produce the yellow color from blood breakdown; a simple protein rise or a normal CSF would not explain the yellow tint. Xanthochromia takes time to develop after bleeding, so its presence supports SAH, and spectrophotometric testing can help confirm bilirubin even when the coloration is subtle.