Cerebrospinal fluid (CSF) is red primarily due to the presence of red blood cells.
Causes of Red CSF
When CSF appears red, it indicates the presence of blood, which is not normal. This can occur for two main reasons:
- Bleeding into the Spinal Fluid: This occurs when there is an actual hemorrhage within the central nervous system. Examples include:
- Subarachnoid hemorrhage: Bleeding in the space surrounding the brain and spinal cord.
- Intraventricular hemorrhage: Bleeding inside the brain's ventricles.
- Traumatic Lumbar Puncture: Also called a spinal tap, a lumbar puncture involves inserting a needle into the spinal canal to collect CSF. If this procedure punctures a blood vessel, some blood can contaminate the CSF sample. This is a common cause of red CSF, and the reference notes that red blood cells can be a result of this procedure.
- The reference specifically notes that red blood cells in the CSF may result from a traumatic lumbar puncture.
How to Differentiate Between Causes
Distinguishing between bleeding into the CSF and a traumatic lumbar puncture is crucial for proper diagnosis and treatment. Here are some clues:
- Appearance of the CSF: A true hemorrhage typically causes the CSF to appear uniformly red in all tubes collected during a lumbar puncture, while a traumatic tap tends to produce CSF that clears as more fluid is collected.
- Xanthochromia: In the case of a true hemorrhage, the CSF will have a yellowish or orange tint (xanthochromia) after a few hours due to the breakdown of red blood cells. This is not seen with a traumatic tap.
- Red Blood Cell Count: A significant increase in red blood cells in the sample further suggests bleeding.
Diagnostic Importance
The appearance of red CSF is an important diagnostic clue. It requires prompt investigation to determine the cause. The reference suggests that red blood cells in the CSF may be a sign of bleeding, so it is crucial to determine if the blood is truly from an ongoing hemorrhage or a result of the lumbar puncture. This is important because the underlying condition that caused the bleeding needs to be addressed immediately.
| Cause | CSF Appearance | Xanthochromia | RBC Count |
|---|---|---|---|
| Bleeding into CSF | Uniformly Red | Present | Elevated |
| Traumatic Lumbar Puncture | Clearing with successive tubes | Absent | May vary |
In summary, red CSF is an important indicator that needs to be evaluated for possible bleeding into the spinal fluid or as a result of a traumatic lumbar puncture. It's critical to distinguish between these causes to ensure appropriate patient management.
