Are pulmonary opacities a marker of pulmonary tuberculosis?

On most occasions treatment of pulmonary tuberculosis is started by physicians based predominantly on radiological opacities. Since these opacities may not be suggestive of active pulmonary tuberculosis and most of these opacities may even remain unchanged after complete treatment, starting treatment solely on the basis of these opacities may lead to ambiguous end points of cure. In view of this, study of misdiagnosis of radiological opacities as active pulmonary tuberculosis by physicians was undertaken in one of the respiratory centers of Armed Forces hospitals.

This was a prospective study of patients referred to our center for confirmation of active disease and institutional therapy. All patients who were diagnosed as pulmonary tuberculosis predominantly on radiological basis by physicians were evaluated for active pulmonary tuberculosis clinically, radiologically and microbiologically. Patients found to have inactive disease were followed for one year. At three monthly review, history, clinical examination, sputum AFB and chest radiographs were done.

There were 36 patients [all males, mean age: 36.9 years (range: 22-46 years)]. The most common initial presentation was of asymptomatic persons (33.3%) reporting for routine medical examination. The commonest radiological pattern was localized reticular opacities (52.8%)On follow up, only one patient was diagnosed to have pulmonary tuberculosis. The final diagnosis was consolidation in 6, bronchiectasis in 8, pulmonary tuberculosis in 1 and localized pulmonary fibrosis in 21 patients.

Diagnosing and treating tuberculosis predominantly on radiological basis is not appropriate and sputum microscopy and culture remains the cornerstone of diagnosing pulmonary tuberculosis.