Analysis of 90 cases of pleural tuberculosis in relation to adenosine deaminase levels

BACKGROUND: To analyze the adenosine deaminase (ADA) pleural levels and the possibility of a typical pattern of tuberculous pleuritis (TP) in relation to these values. PATIENTS AND METHODS: We analyzed 90 consecutive cases of TP dividend into two groups on the basis of the pleural ADA measurements: group 1 (less than 43 U/I) and group 2 (equal or higher than 43 U/I). We compared: age, sex, tuberculous risk factors, clinic onset and duration, PPD, chest roentgenogram, biochemical (LDH, glucose and proteins) and cytological examination of the pleural fluid, microbiologic studies on sputum, pleural fluid and biopsies, histologic findings of the biopsies, evolution and sequelae after the treatment. RESULTS: 36 patients in the group 1 (40%) and 54 in the group 2 (60%) (p = 0.01). All the parameters were similar in both groups excluding LDH pleural levels, that were higher in group 2. In 20 cases of the group 1, we obtained a second analysis of pleural ADA and we observed in 11 cases (55%) an ADA value above 43 U/I. CONCLUSIONS: We confirmed that ADA pleural level is increased in the majority of our patients with a low initial sensibility of 60%, that can increase with a second determination (72%). ADA activity below 43 U/I cannot exclude the tuberculous aetiology of an effusion and can persist negative in other analyses. The results suggest a response of different chronology without any relation to initial ADA pleural level.