II. Pathophysiology: Xanthochromia
- Xanthochromia is yellow, red or orange supernatant discoloration of centrifuged CSF (due to oxyhemoglobin, Bilirubin)
- Hemoglobin breaks down into oxyhemoglobin (after 2 hours) and then Bilirubin (after 10 hours)
- Indication of free Hemoglobin or a breakdown product in the CSF
- Follows RBC lysis, occuring within hours of at least 400 RBCs first present in CSF
- Xanthochromia may persist for 2 weeks after bleeding event
III. Technique
- Count Red Blood Cells in first and third tubes
IV. Interpretation: For each 500-1000 RBCs/mm3
- CSF Leukocytes increase by 1
- CSF Protein rises 1 mg/deciliter
V. Causes: CSF Red Blood Cells
-
Subarachnoid Hemorrhage or Intracranial Bleeding
- RBC Count unchanged between first and third tubes
- Blood does not clot
- Xanthochromia suggests bleeding
-
Traumatic tap
- RBC Count decreases between first and third tubes
- CSF becomes clear on centrifugation
- Consider repeating tap at higher interspace
VI. Causes: Xanthochromia
-
Subarachnoid Hemorrhage
- Xanthochromia at 6 hours: 20% of Subarachnoid Hemorrhage
- Xanthochromia at 12 hours: 90% of Subarachnoid Hemorrhage
- Sentinel bleeds in prior 2 weeks in half of SAH patients may also persist as Xanthochromia
- Increased Serum Bilirubin >10-15 mg/dl
- CSF Protein >150 mg/dl
- Traumatic Lumbar Puncture (if CSF RBC>100,000)
VII. References
- Aldeen and Rosenbaum (2017) 1200 Questions Emergency Medicine Boards, 3rd ed, Wolters Kluwer, Baltimore, p. 123
- Kooiker in Roberts (1998) Procedures in ER, p. 1067-75
- Ravel (1995) Lab Medicine, Mosby, p. 294-9
- Tunkel in Mandell (2000) Infectious Disease, p. 974-8
- Seehusen (2003) Am Fam Physician 68:1103-8 [PubMed]