Atypical locations of pulmonary tuberculosis and the influence of the roentgenographic patterns and sample type in its diagnosis.

In 97 cases of pulmonary tuberculosis (PTB), we analyzed the incidence of atypical roentgenographic locations, roentgenographic patterns, the correlation between the diagnostic yield and the roentgenographic pattern and the usefulness of simple or induced sputum (82 cases), bronchoaspirate (BAS; 29 cases), postfiberoptic bronchoscopy sputum (PFBS; 16 cases) and how the different tests supplemented each other. Atypical locations were defined as those not corresponding to classic primary and postprimary PTB. This atypical-location PTB index was 8.2%, and roentgenographic patterns found most frequently were: destructive 52.5%, destructive-alveolar 20.6% and alveolar 12.3%. Lowenstein-Jensen (LJ) culture of the sputum of alveolar-pattern cases improved acid-fast bacillus (AFB) diagnosis by 46% (p < 0.005), in contrast to other radiologic patterns. Simple or induced sputum proved to be a very good diagnostic specimen in 98% of the cases (AFB staining 73.1% and LJ culture 89%). BAS increased the sputum yield by 21% and PFBS contributed only 1 additional case to the results obtained with BAS. Therefore, BAS is a very good supplemental test in cases of false-negative findings.