[Tuberculosis presenting as diffuse pulmonary infiltrates in AIDS patients: diagnostic performance of clinical...

In patients with human immunodeficiency virus (HIV) infection, tuberculosis is frequently presented with diffuse pulmonary infiltrates which are indistinguishable from those caused by other respiratory pathogens. It is therefore useful to know the diagnostic performance of different clinical samples.

We have retrospectively analyzed the clinical histories of 56 patients seen over a 3-year period. All the patients had HIV infection, Mycobacterium tuberculosis isolated in at least one clinical sample and presented with diffuse bilateral infiltrates in thorax radiography. The results of all the clinical samples submitted to the microbiology laboratory.

The highest performance in both stainings and cultures were obtained from the biopsy (or aspirate) of adenopathies (93 and 100%, respectively), sputum (57 and 88%) and urine (31 and 64%). A lower than expected sensitivity was obtained in the fibrobronchoscopy samples (bronchoalveolar lavage and transbronchial biopsy). The staining had low sensitivity for predicting positive cultures in all the samples except in the adenopathies. Visualization of granulomas in transbronchial biopsies and bone marrow was more sensitive for diagnosis than the demonstration of resistant acid-alcohol bacilli in the same samples. Globally, rapid diagnosis was obtained in 43 patients (76%). The remaining 13 (24%) patients were not diagnosed until the culture results had been received despite the adequate use of diagnostic procedures.

These findings support the use of empiric treatment when tuberculosis is suspected despite initial negativity of the microbiologic and pathologic examinations following the discarding of other potential causes.