Assessment of Csf Ada and Crp Levels in Differential Diagnosis of Meningitis in Adults
Author(s): D Prashanth and Dr. Subash kumar CH
Background and Objectives: Infections involving the CNS, particularly meningitis and encephalitis are likely to arouse tremendous
anxiety in both the physician and patients. Reliable, cost effective, rapid diagnostic tests which can be performed in any standard pathology
laboratory could be of help in the differentiation of various types of meningitis in adults. In this regard, C - reactive protein level and
Adenosine deaminase activity can be used as rapid tests in the differential diagnosis of meningitis. ADA estimation is useful in diagnosis of
Tuberculous meningitis. CRP estimation has been documented to be helpful in diagnosing pyogenic meningitis. The levels of both ADA and
CRP are low in cases of viral meningitis. Objective: Assessment of cerebrospinal fluid Adenosine deaminase and C Reactive protein in the differential diagnosis of meningitis in
adults. Methods: CSF samples were obtained from 50 patients who presented to the casualty and Outpatient department of Osmania General
Hospital During September 2012 to September 2014 Diagnosis of meningitis was based on the clinical presentation and CSF analysis.
Results: In our study, out of a total of 50 patients, 25 patients were diagnosed as tubercular meningitis based on the clinical features and
CSF analysis. The mean ADA activity was 14.36 in the Tuberculous meningitis group, the result being statistically significant (p<0.001). The
sensitivity and specificity was 72% and 100% respectively when a cut-off value of ADA of 10U/l was used.
CSF-CRP is significantly higher in pyogenic meningitis compared to non-pyogenic meningitis. The sensitivity and specificity of the test was
90% and 100%respectively with an accuracy of 98%. Interpretation and Conclusion: 2 rapid diagnostic tests-CRP and ADA activity in the CSF can help in the differential diagnosis of pyogenic
from non-pyogenic and tubercular from viral meningitis respectively, CRP being elevated in pyogenic meningitis and ADA activity noted
to be higher in tuberculous meningitis. The levels of ADA and CRP are low in viral meningitis. However, these tests should be interpreted
judiciously in the light of the patients’ clinical manifestations and the results of CSF analysis.