What is the significance of a cerebrospinal fluid (CSF) cell count with a differential count showing 42% Segmented Neutrophils (Segs) and 58% Lymphocytes?

From the Guidelines

The cerebrospinal fluid (CSF) cell count differential showing 42% segmenters (neutrophils) and 58% lymphocytes is indicative of a mixed inflammatory response, suggesting an ongoing infectious or inflammatory process in the central nervous system, which may require further diagnostic testing such as CSF lactate concentration, PCR, or CSF culture to determine the underlying cause and appropriate treatment. The presence of a significant lymphocyte percentage (58%) in the CSF differential count may suggest a viral infection or a partially treated bacterial infection, as viral infections typically show lymphocyte predominance (>70%) 1. However, the presence of 42% neutrophils (segmenters) indicates that a bacterial infection cannot be ruled out entirely, especially in the early stages or if the patient has been partially treated with antibiotics. According to the ESCMID guideline on the diagnosis and treatment of acute bacterial meningitis 1, CSF lactate concentration is a useful diagnostic test for differentiating bacterial meningitis from other types of meningitis, with a higher diagnostic accuracy than CSF WBC count. Key considerations in interpreting this CSF differential count include:

• The total cell count in the CSF, as normal CSF should contain very few cells (typically less than 5 white blood cells per microliter)
• Other CSF parameters such as protein and glucose levels
• Clinical symptoms and additional diagnostic tests such as CSF culture, PCR for specific pathogens, or imaging studies to determine the underlying cause and appropriate treatment. It is essential to correlate these findings with clinical presentation and other diagnostic results to guide further management, as the mixed inflammatory response indicated by this CSF differential count can be associated with various conditions, including viral infections, partially treated bacterial infections, or non-infectious inflammatory conditions 1.

From the Research

Cerebrospinal Fluid Cell Count Differential Count

• The given cerebrospinal fluid (CSF) cell count differential count is 42% segmenters and 58% lymphocytes.
• This information can be useful in diagnosing and differentiating between various types of meningitis, as different pathogens can cause different types of white blood cell responses in the CSF 2, 3.
• However, the provided studies do not directly address the specific differential count of 42% segmenters and 58% lymphocytes.
• Study 4 discusses the use of flow cytometry in analyzing CSF samples, which can help identify different types of immune cells, including T lymphocytes and B lymphocytes.

Diagnostic Implications

• The presence of a high percentage of lymphocytes in the CSF can indicate a viral or chronic infection, while a high percentage of segmenters (neutrophils) can indicate a bacterial infection 2, 3.
• However, without more specific information about the patient's symptoms, medical history, and other laboratory results, it is difficult to determine the exact cause of the meningitis.
• Further testing, such as real-time PCR or culture, may be necessary to confirm the diagnosis and guide treatment 5, 2, 6.

Limitations of Current Evidence

• The provided studies do not directly address the specific question of what a CSF cell count differential count of 42% segmenters and 58% lymphocytes means.
• More research is needed to fully understand the implications of this specific differential count and how it relates to different types of meningitis.