Diagnostic value of pleural fluid interferon-gamma and adenosine deaminase in patients with pleural tuberculosis in Qatar.

OBJECTIVE: To investigate the diagnostic utility of interferon-gamma (IFN-γ) and adenosine deaminase (ADA) in tuberculous pleural effusions by determining the best cutoff levels of these two markers for pleural tuberculosis, in the context of the local epidemiological settings in Qatar. METHODS: We prospectively studied IFN-γ and ADA levels in the pleural fluid of patients presenting to Hamad General Hospital between June 1, 2009 and May 31, 2010. RESULTS: We studied 103 patients with pleural effusions, 72 (69.9%) with pleural tuberculosis, and 31 (30.1%) with nontuberculous etiologies. The mean IFN-γ concentration for the group with tuberculous effusions was significantly higher than that in the group with nontuberculous effusions (1.98 ± 81 vs 0.26 ± 10 pg/mL [P < 0.0001]). The mean ADA activity for the tuberculous effusions group was significantly higher than that in group with nontuberculous effusions (41.30 ± 20.09 vs 14.93 ± 14.87 U/L [P < 0.0001]). By analysis of receiver operating characteristic (ROC) curves, the best cutoff values for IFN-γ and ADA were 0.5 pg/mL and 16.65 U/L, respectively. The results for IFN-γ vs ADA were: for sensitivity, 100% vs 86%, respectively; for specificity, 100% vs 74%, respectively; for positive predictive value, 100% vs 88.5%, respectively; and for negative predictive value, 100% vs 69.7%, respectively. CONCLUSION: IFN-γ and ADA could be used as valuable parameters for the differentiation of tuberculous from nontuberculous effusion, and IFN-γ was more sensitive and specific for tuberculous effusion than ADA.

Primary Nocardia meningitis in a patient without a predisposing condition: case report and review of the literature.

A case of primary Nocardia meningitis in a patient without a predisposing condition is presented and 4 other reported cases are reviewed. The presenting features were fever, headache, altered consciousness, and neck stiffness. Cerebrospinal fluid examination (CSF) revealed hypoglycorrhachia (<40 mg/dl), elevated protein (>100 mg/dl), and pleocytosis with predominant neutrophils in all patients. Culture of CSF was positive for Nocardia in 4 of the 5 patients. Mortality was 50%. Diagnosis was frequently delayed and this probably contributed to the high mortality. Compared with Nocardia meningitis in association with a predisposing condition, primary Nocardia meningitis without a predisposing condition has similar clinical features and outcome.