CSF xanthochromia is associated with all except-
. *CSF colour :blood stained xanthochromic is characteristic feature of subarachnoid hemorrhage. Cerebrospinal fluid, which fills the subarachnoid space between the arachnoid membrane and the pia mater surrounding the 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 enzymes to bilirubin, a yellow pigment. The most common cause for bleeding into the subarachnoid space is a subarachnoid hemorrhage from a ruptured cerebral aneurysm. 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. 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 seizures, 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.According to one aicle, 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. Heme from red blood cells that are in the cerebrospinal fluid because a blood vessel was nicked 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 Ref Harrison20th edition pg 2345
Hypercarotenemia
Hyperbilirubinemia
Previous traumatic or bloody tap
none
C.N.S