Lower lung field tuberculosis: a clinical study from tertiary care teaching hospital of North Karnataka

Abstract

Pulmonary tuberculosis in the adult may present with unusual X-ray patterns that may lead diagnosis in the direction other than tuberculosis. This one year prospective study was designed to identify its prevalence in different clinical conditions, its common clinical and radiological presentations, diagnosis and outcome of treatment. All the patients of pulmonary tuberculosis who had lesions below an arbitrary line across the hila in theirchest X-rays were included in this study as cases. Sputum for AFB, blood sugar, HIV testing and other relevant investigations were performed in each patient. The usefulness of bronchoscopy in bacteriologic diagnosis was noted. Out of a total of 813 cases of pulmonary tuberculosis patients, 25 cases had lower lung field tuberculosis. It was more common in females 14(56%) than in males 11(44%). Majority of patients 16(64%) were in the 16-40 years age group. Risk factors were diabetes in 11, HIV in 3, pregnancy and lung cancer 2 cases each. Unilateral disease was more common 19(76%) and the right side was more frequently affected 15(60%). Consolidation 16(64%), cavitation 5(20%) and nodular opacities 4(16%) were the mainradiological findings. In conclusion, diagnosis requires a high index of suspicion. Diabetes mellitus, HIV, pulmonary malignancy and pregnancy increase the risk of lower lung field tuberculosis. Fiberoptic flexible bronchoscopy helps in diagnosis in sputum negative cases. Clinical presentation is similar to that of classical upper lung fieldtuberculosis and short course chemotherapy is equally effective as in classical upper zonal disease.