Radiological Pattern of Pulmonary Tuberculosis in Diabetes Mellitus

Abstract

Background:  Tuberculosis is one of the most serious public health problem globally. About one third of the population has been infected with mycobacterium tuberculosis. Post primary tuberculosis has been classically considered as a disease causing patchy opacity or with cavitatory or calcified lesion, in one or both upper lung lobes. On the other hand, diabetes mellitus is also a major public health problem. Worldwide prevalence of diabetes is 4%, while in Pakistan prevalence of diabetes is 4.5 - 11% making Pakistan 6^th in world ranking of diabetes mellitus prevalence. When two diseases are common, these can effect each other in terms of clinical presentation and course of the disease. In pulmonary tuberculosis with diabetes mellitus radiological pattern of may be different from patients without diabetes mellitus.

Objective:  To determine the radiological pattern of pulmonary tuberculosis in diabetes mellitus.

Study Design:  A prospective-observational study.

Place of Study:  The study was conducted in B.V. Hospital, Bahawalpur.

Duration of Study:  The study was conducted from January 2004 to December 2006.

Material and Methods:  One hundred and fifty patients with diabetes mellitus (both type 1 and type 2) and pulmonary tuberculosis were included in the study. Pulmonary tuberculosis was diagnosed on the basis of AFB positive sputum, history and radiological findings suggestive of pulmonary tuberculosis. Two physicians (including one chest physician) and a radiologist reviewed the chest radiographs. Those x-rays were selected in which there was no difference of opinion. Diabetic patients were either known diabetics or they were newly diagnosed based on WHO criteria.

Results:  A total of 150 patients were analyzed in which there was 105 were male and 45 females. The age range was 18 years to 75 years. The mean age was 49.81 and standard deviation was +12.28. Out of 150 films 69 (46%) showed the typical pattern (patchy infiltration / nodular pattern with or without cavitation) involving upper zone. While 81 (54%) pts showed the atypical pattern with lower lung field involvement. Out of 150 films, in 84 right lung was involved, in left lung about 39 and bilateral lesion found in 27 films. In 75 films x-rays showed non homogeneous opacity, cavity in 31 and homogeneous shadows in 22 and multiple shadows in 22 films. Among lower lung field involvement with pulmonary tuberculosis 50.6% were above the age of 50 years.

Conclusion:  Atypical pattern of pulmonary tuberculosis is the common mode of presentation in elderly and diabetic patients.

Keywords:  Pulmonary tuberculosis, Diabetes Mellitus, Typical pattern, Atypical pattern.