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Immediate diagnosis of ventriculits: evaluation of parameters independent of microbiological culture

BACKGROUND

Generally accepted reference values in CSF diagnostics are not valid in cerebrospinal fluid (CSF) containing large amounts of blood. Residual blood may obscure ventriculitis as diagnostics largely depend on parameters such as cell count, lactic acid and total protein measurement. We sought to improve the diagnostics by evaluating a cytokine panel and soluble CD62L as markers of ventriculitis. In addition, we tested an algorithm of established parameters to predict ventriculitis in a specific patient collective.

METHODS

Analysis was performed on ventricular CSF samples from 50 consecutive patients. Gram staining, microbiological culture, total cell count, total protein and CD62L expression on neutrophil granulocytes were analysed immediately. Cytokines and soluble CD62L were measured by flow cytometry.

FINDINGS

Positive culture was detected in ten patients. Of all parameters tested only IL1-beta, IL8 and CD62L on neutrophils were significantly different between culture-positive and -negative patients. The highest predictive value was obtained when analysing IL1-beta. The predictive value of a parameter combination (IL6 in CSF, C-reactive protein and leukocytes in periphereal blood) was comparable to IL1-beta. Half of the patients in this analysis were identified as culture positive because of the lack of inflammatory response.

CONCLUSIONS

IL1-beta and perhaps also IL8 provide very good analytical performance when looking for ventriculitis in patients with residual blood in CSF. Turn-around time is short, and results could be reported within 1 h for 24 h a day. In some patients application of glucocorticoids may result in restricted inflammatory response. Even in these patients IL1-beta provides a reliable parameter for the immediate diagnosis of ventriculitis.

CD62L on neutrophil granulocytes, a useful, complementary marker for the prediction of ventriculitis in blood-containing CSF

OBJECTIVES

Presence of residual blood is a common problem in cerebrospinal fluid (CSF) diagnostics of ventriculitis. We hypothesised that neutrophil granulocytes in infected, blood-containing CSF lose CD62L expression. Therefore CD62L expression on neutrophils may present a complementary marker to distinguish between patients with residual blood and infection.

DESIGNS AND METHODS

Evaluation was performed in 64 ventricular CSF samples sent to the laboratory for diagnostic investigation. Cell count, microbiological culture, total protein and flow cytometric analysis of CSF were performed.

RESULTS

Cell counts and CD62L expression were significantly different between the culture positive and negative group. ROC-analysis revealed a significant predictive value for cell count and CD62L expression. Optimal cut-offs were calculated and a decision tree was established to predict a positive culture.

CONCLUSIONS

Cell count and CD62L expression were predictive for a positive culture and the combination helped to increase specificity and sensitivity for the detection of ventriculitis in blood-containing CSF.

Determination of leukocytosis in traumatic spinal tap specimens

White and red blood cell counts from peripheral blood and from the cerebrospinal fluid of all patients who had traumatic lumbar punctures over a five-year period were studied to determine the diagnostic value of using the ratio of white blood cells to red blood cells in peripheral blood to adjust the white blood cell count found in the bloody cerebro-spinal fluid. In patients without meningitis, 55 percent of the cerebrospinal fluid specimens had more white blood cells than could be attributed to trauma. However, in only 10 percent was the actual white blood cell count more than 10 times greater than the number referable to trauma. In 38 percent, there were fewer white blood cells in the cerebrospinal fluid than the ratio predicted. Such underestimation was uncommon among patients with culture-positive meningitis: the ratio failed to detect leukocytosis in only 10 percent, and all but one of these patients had clinical reasons for the low cerebrospinal fluid count. It is concluded that true leukocytosis is rarely masked in blood-contaminated cerebrospinal fluid, and that the presence of more than 10 times the number of white blood cells than allowed by the adjustment is a sensitive and specific indicator of meningitis. However, a simple mechanical use of the formula is not justified, and all available clinical and laboratory data should be used when deciding whether to institute treatment in a patient with possible meningitis and bloody spinal fluid.