From the Guidelines
A WBC count of 13 in CSF is mildly elevated and warrants further investigation to determine the underlying cause of the inflammation or infection in the central nervous system. Normal CSF typically contains 0-5 WBCs per microliter, so a count of 13 is slightly above the normal range. According to the guidelines by the Infectious Diseases Society of America 1, CSF analysis is essential for evaluating patients with encephalitis, and a mild mononuclear pleocytosis is typically seen in viral encephalitis. However, a polymorphonuclear cell predominance may be observed if the sample is obtained early in the course of illness.
The clinical context is crucial for interpreting the CSF WBC count, and symptoms such as fever, headache, neck stiffness, or altered mental status would increase concern for an infectious or inflammatory process. Potential causes of a mildly elevated CSF WBC count include partially treated bacterial meningitis, viral meningitis, early bacterial infection, fungal infection, or non-infectious inflammatory conditions.
Additional CSF parameters, such as protein levels, glucose, cell differential, and microbiological studies, should be evaluated to help determine the underlying cause of the elevated WBC count. The guidelines also recommend considering the use of nucleic acid amplification tests, such as PCR, to diagnose certain viral CNS infections 1. If infection is suspected, empiric antimicrobial therapy might be considered while awaiting culture results, especially if the patient appears ill or has other concerning clinical features.
It is essential to note that a CSF WBC count of 13 is not severely abnormal, and the patient's clinical presentation and other laboratory values should be taken into account when determining the best course of action. As stated in the guidelines, the presence of CSF eosinophils may suggest certain etiologic agents, and accurate laboratory identification of these cells is important 1.
In terms of diagnosis, serologic testing, viral culture or antigen detection in brain, and MRI may also be useful in determining the underlying cause of the elevated CSF WBC count 1. However, the CSF WBC count alone is not diagnostic and must be interpreted alongside other laboratory values and the patient's clinical presentation. Therefore, further investigation and evaluation of the patient's clinical presentation and laboratory values are necessary to determine the underlying cause of the mildly elevated CSF WBC count.
From the Research
CSF White Blood Cell Count
- A white blood cell (WBC) count of 13 in the cerebrospinal fluid (CSF) may indicate the presence of an infection or inflammation in the central nervous system.
- According to a study published in 2019 2, a corrected CSF WBC count can be a useful indicator of healthcare-associated ventriculitis or meningitis (HCAVM) in adults with intracranial hemorrhage.
- The study found that cases of HCAVM had significantly higher CSF WBC counts (both uncorrected and corrected) compared to controls.
Treatment of Bacterial Meningitis
- The treatment of bacterial meningitis typically involves the use of antibiotics, such as ceftriaxone or vancomycin.
- Ceftriaxone has been shown to be effective in treating bacterial meningitis, with a high bactericidal titer in the CSF and a rapid onset of action 3, 4.
- Vancomycin is also recommended as part of empiric therapy for suspected bacterial meningitis, particularly in cases where ceftriaxone-nonsusceptible pneumococcal meningitis is suspected 5, 6.
Diagnostic Challenges
- The diagnosis of HCAVM in patients with intracranial hemorrhage can be challenging, and no single parameter is sufficient for diagnosis.
- The cell index, which takes into account the CSF WBC count and other factors, has been found to be a useful indicator of infection in patients with ICH 2.
- Further studies are needed to develop more accurate diagnostic models for HCAVM and to improve treatment outcomes for patients with this condition.