From the Guidelines
The CSF results are most consistent with a traumatic lumbar puncture, given the elevated RBC count of 4248 cells/μL and normal WBC count of 5 cells/μL, glucose of 85 mg/dL, and protein of 31 mg/dL, as supported by the guidelines for the management of suspected viral encephalitis in adults 1. The normal white blood cell count and the absence of significantly elevated protein or decreased glucose levels argue against an infectious or inflammatory process such as meningitis or encephalitis. According to the management of encephalitis guidelines by the Infectious Diseases Society of America 1, a traumatic tap can be suspected when there is an elevated RBC count in the CSF, which is likely due to blood contamination during the procedure. Some key points to consider in the interpretation of CSF results include:
- The presence of a mildly elevated CSF protein and a normal CSF:plasma glucose ratio, which is typically seen in viral encephalitis 1
- The possibility of a traumatic tap, which can be suspected when there is an elevated RBC count in the CSF, as seen in this case 1
- The importance of considering the clinical context and other diagnostic studies when interpreting CSF results, as some cases of encephalitis may have normal or nonspecific CSF findings 1 Given the information provided, the most likely explanation for the CSF results is a traumatic lumbar puncture, and further evaluation for subarachnoid hemorrhage or other pathology may not be necessary unless there are other clinical indications 1.
From the Research
CSF Analysis Interpretation
The given CSF analysis results are:
- WBC: 5
- RBC: 4248
- Glucose: 85
- Protein: 31
Red Blood Cell Count
The high RBC count of 4248 suggests the presence of blood in the cerebrospinal fluid, which could be indicative of a subarachnoid hemorrhage (SAH) 2. However, it is essential to consider that a traumatic lumbar puncture can also cause an elevated RBC count.
Protein Levels
The protein level of 31 is slightly elevated, which may be associated with an unfavorable functional outcome in spontaneous subarachnoid hemorrhage, as elevated CSF protein levels have been linked to poor outcomes 3.
White Blood Cell Count
The WBC count of 5 is relatively low, which may not be indicative of an infection. However, it is crucial to consider that CSF WBC count can remain elevated throughout the 14 days following a subarachnoid hemorrhage, even when corrected for red blood cell count (RBC) 4.
Glucose Levels
The glucose level of 85 is within the normal range, which does not provide any specific indication of a subarachnoid hemorrhage or other conditions.
Diagnostic Considerations
In patients with suspected subarachnoid hemorrhage, a combination of computed tomography (CT) scans and lumbar puncture is often used for diagnosis. Fifth-generation CT scanners have been shown to be highly sensitive in detecting SAH 5. However, in cases where CT scans are negative, lumbar puncture can help confirm the diagnosis. The presence of xanthochromia, a yellow discoloration of the cerebrospinal fluid, can be used to distinguish between a traumatic lumbar puncture and a subarachnoid hemorrhage, but it is not a definitive indicator 2.
Key Findings
- Elevated RBC count suggests possible subarachnoid hemorrhage or traumatic lumbar puncture
- Slightly elevated protein levels may be associated with unfavorable outcomes in spontaneous subarachnoid hemorrhage
- Normal glucose levels do not provide specific indications
- Low WBC count may not be indicative of infection, but can remain elevated after subarachnoid hemorrhage
- Combination of CT scans and lumbar puncture is essential for diagnosis of subarachnoid hemorrhage 6, 2, 4, 5