From the Guidelines
The presence of red blood cells in cerebrospinal fluid is abnormal and typically indicates bleeding within the central nervous system or traumatic lumbar puncture, and management depends on the cause and severity, with traumatic taps often requiring observation and true subarachnoid hemorrhage necessitating immediate neurosurgical consultation and potential intervention.
Key Considerations
- The significance of red blood cells in CSF can vary, with minimal counts (<100/μL) often being clinically insignificant, moderate counts (100-10,000/μL) warranting investigation, and high counts (>10,000/μL) strongly suggesting pathological bleeding 1.
- Distinguishing between traumatic tap and true bleeding is crucial and can be done by examining RBC counts in sequential CSF tubes, checking for xanthochromia, and correlating with clinical presentation and neuroimaging.
- In cases of suspected viral encephalitis, such as HSV encephalitis, a blood-stained CSF sample may reflect the hemorrhagic pathophysiology of the condition, and serial CSF specimens may be necessary to determine the cause of the bleeding 1.
Management Approach
- For traumatic taps, observation is usually sufficient as RBCs will clear naturally.
- For true subarachnoid hemorrhage, immediate neurosurgical consultation is required, often with admission to intensive care, blood pressure control, and possibly neurosurgical intervention.
- Proper interpretation of RBCs in CSF requires consideration of clinical context, timing of collection, and other CSF parameters, such as glucose and protein levels, to guide appropriate management decisions 1.
Clinical Context
- The presence of red blood cells in CSF can be associated with various conditions, including viral encephalitis, bacterial meningitis, and traumatic injury, and a thorough clinical evaluation is necessary to determine the underlying cause 1.
- In patients with suspected CNS infections, such as viral encephalitis, the presence of RBCs in CSF may indicate a hemorrhagic component, and further evaluation, including neuroimaging and serial CSF analysis, may be necessary to guide management 1.
From the Research
Significance of Red Blood Cells in CSF
- The presence of red blood cells (RBCs) in cerebrospinal fluid (CSF) can be an indicator of various conditions, including subarachnoid hemorrhage (SAH) 2, 3.
- Studies have shown that lower RBC counts in CSF are associated with good functional outcome and hospital survival in patients with SAH 2, 3.
- High RBC counts in CSF can correlate with radiological measurements of SAH volume, such as modified Fisher score and Hijdra ventricle score 3.
Management of Red Blood Cells in CSF
- The detection of RBCs in CSF is a widely available part of neurological routine diagnostics, but the prognostic value as a biomarker remains unclear 3.
- Xanthochromia, the yellow discoloration of CSF caused by hemoglobin catabolism, is not pathognomonic for SAH and can be observed in traumatic lumbar puncture (LP) 4.
- Correction of CSF protein for the presence of RBCs is important, as CSF protein can increase by 1.1 mg/dL for every 1000 cell increase in CSF RBCs per mm(3) 5.
- On-chip cell staining and counting platforms can be used for rapid detection of blood cells in CSF, allowing for simple and accurate cell counting 6.
Clinical Implications
- Clinicians should not rely solely on xanthochromia to confirm SAH, especially when the CSF RBC count is elevated above 10,000 RBC/μL or the time between sample acquisition and analysis is prolonged 4.
- Low CSF RBC counts can predict hospital survival and good functional outcome after 3 months in patients with SAH 3.
- Further investigation is needed to determine the relationship between CSF RBC counts and functional outcome in patients with SAH 2, 3.