Study of C-Reactive Protein & Adenosine Deaminase Levels in CSF Analysis of Patients with Meningitis
Keywords:CSF; C-Reactive Protein; Adenosine Deaminase; Pyogenic Meningitis; Tuberculous Meningitis
Background and Objectives: CNS infections continue to pose challenges to the treating physician. It is essential to make an accurate etiological diagnosis and institute appropriate treatment at the earliest in such cases. This requires diagnostic tests which can help differentiate the various forms of meningitis. CSF C-Reactive Protein and Adenosine Deaminase are two such tested parameters to differentiate the types of meningitis, and it is observed that ADA is elevated in tuberculous meningitis and CRP in pyogenic meningitis. Our objective was to assess the combined utility of these tests in our setup and to ascertain an optimal cut-off value for Adenosine Deaminase.
Method: 50 patients who were diagnosed with meningitis based on clinical features and routine CSF analysis, during the study period were selected. ADA and CRP levels in CSF of these patients were analysed.
Results: In our study out of 50 patients, 22 were diagnosed with tuberculous, 20 with viral and 6 with pyogenic meningitis. The mean ADA levels were 17±8.5 IU/L in the tuberculous meningitis group which was higher than the other groups and this was statistically significant (p value-0.003).
With a cut-off value of 10IU/L, sensitivity & specificity of ADA in our setup was 86% and 63.63% respectively. Using an ROC curve analysis a more optimal cut-off value of 12.9IU/L was suggested.
The mean CRP values was 3.22±1.9mg/L in pyogenic meningitis and the value was significantly higher (p-value < 0.0001) than the other groups. The sensitivity and specificity of CRP in our setup was 83% and 71% respectively.
Conclusion:ADA levels are elevated in CSF of patients with tuberculous meningitis and CRP levels in patients with pyogenic meningitis. In view of low specificity of ADA, caution may have to be exercised in utilizing the test. Calculation of optimal cut-off at different setups may improve decision making