2020, Vol. 2, Issue 2, Part D

Tubercular meningitis is a type of septic meningitis is a significant cause of morbidity and mortality in developing countries like India due to lack of early and timely diagnosis case fatality remains higher. Even when not fatal, the sequels are distressing and disabling.

Cerebrospinal fluid (CSF) evaluation is single most important aspect of lab diagnosis in meningitis, Analysis of CSF abnormalities to a great deal facilitates the diagnosis and initial therapy. Basic studies of CSF includes measure of pressure, cell count, cell types and estimation of glucose, protein and chloride levels and also grams staining and culture.

The definitive diagnosis of tubercular meningitis depends on detection of acid-fast bacilli (AFB) and culture of mycobacterium tuberculosis from CSF specimen but AFB is seen on direct smear of CSF sediment in only 20% of cases and it takes 4-8 weeks to be grown in culture. Hence there is a need for test like levels of Adenosine deaminase (ADA) for assistance in diagnosis of tubercular meningitis and to differentiate it from other causes of meningitis.

Materials and Methods: Minimum 100 patients, both male and female with symptoms suggestive of meningitis over a period of 1 and half years, admitted SIMS, Hyderabad were included in this study and the following investigations were done.

It was clinical cross sectional study of 25 cases of Tuberculosis, 25 cases of pyogenic meningitis and 25 cases of aseptic meningitis. 25 controls with age and sex matched individuals without evidence of any neurological diseases served as control for CSF ADA. Study was conducted to evaluate the usefulness of levels of ADA in diagnosis of tubercular meningitis and to compare the levels of ADA in different types of meningitis for early and rapid diagnosis of meningitis.

Results: In this study of 100 patients, 25 (100%) patients of the tubercular group had CSF ADA levels of more than 10 IU/dL with a mean of 13.68 IU/dL with 80% of the patients having ADA levels between 11 and 15 IU/dL. Mean ADA levels of aseptic meningitis was 8.00 IU/dL, pyogenic was 5.76 IU/dL and control group had mean ADA of 2.12 IU/dL.

Conclusion: All patients with tubercuolous meningitis had elevated CSF ADA activity. CSF ADA activity in tuberculous meningitis was significantly higher when compared to pyogenic meningitis, aseptic meningitis and controls. Elevated levels of CSF ADA had very high sensitivity and specificity in diagnosis of tuberculous meningitis. Estimation of CSF ADA is a simple, cheap, rapid, and fairly specific method that helps in early diagnosis of tuberculous meningitis and can be included in the routine investigation of tuberculous meningitis.