Background: The aim of the present study was to analyze the diagnostic profitability of echography as an indicator of extrapulmonary tuberculosis in patients with HIV infection.
Patients and methods: HIV positive patients presenting fever of long duration were prospectively studied with an active search for specific echographic lesions. Descriptive statistics were performed by variance analysis. The diagnostic profitability of echography was evaluated by the calculation of sensitivity, specificity, positive predictive values (PPV) and negative predictive value (NPV).
Results: Criteria of prolonged fever was fulfilled by 116 patients. Thirty-five (30.2%) presented specific echographic alterations: 12 had multiple hyoechoic splenic lesions (34.3%), 11 abdominal adenopathies (31.4%), 9 splenic lesions and adenopathies (25.7%) and 3 showed hepato-splenic involvement and adenopathies (8.6%). The final diagnoses of these patients were: one case of toxoplasmosis, 2 MAI infection, 7 with no definitive diagnosis, and 25 (71.4%) tuberculosis. The mean CD4 lymphocyte count was 46.6 x 10(6)/L in patients with tuberculosis with no echographic findings, with a statistically significant difference of p < 0.05. The appearance of some echographic alterations had a global sensitivity of 37.3%, a specificity of 79.6% a PPV of 0.65 and a NPV of 0.51. The isolated findings of hypoechoic splenic lesions showed a sensitivity of 19.23%, a specificity of 95.12%, a PPV of 0.83 and a NPV of 0.47.
Conclusions: The presence of multiple hypoechoic splenic lesions showed an elevated specificity, being greater than 95%, making this finding, although infrequent, that of greatest diagnostic profitability in the echographic study of tuberculosis. We therefore consider abdominal echography to be of great usefulness in the evaluation of patients with HIV infection and prolonged fever since the presence of these lesions, in the most severely immunosuppressed patients, may strongly suggest the diagnosis of extrapulmonary tuberculosis.