Comparative Study Of CT Appearance Of TB In Diabetic And Non-diabetic Patients: Findings Before And After Anti-tuberculous Therapy

OBJECTIVE: To evaluate the CT features of pulmonary tuberculosis in diabeticpatients compared with non-diabetic patients before and after anti-tuberculos treatment.MATERIALS AND METHODS: CT scans of the chest in71adult patients withactive post primary tuberculosis were reviewed.41patients with no underlying disease,30patients with diabetes mellitus. CT scans were performed before and afteranti-tuberculous treatment. The CT features and follow-up appearances of them were acomparative study.RESULTS: In non-diabetic patients28had consolidation. Characteristic featuresof tuberculosis in this group of patients included segmental distribution (98%), cavitarylesion (32%),"tree-in-bud" appearance (61%), Bronchiectasis (41%). Thedisappearance of “tree-in-bud” appearance, pleural effusion and the presence of fibroticchange appear to be indications of the effectiveness of treatment. Ground-glass patternwas noticed10times before treatment,6times after3month treatment and only2timesafter6month treatment. Reticular pattern (intralobular and septal thickening),interstitial nodules, and fibrosis were seen both before and after treatment. In diabeticpatients,23had consolidation. Diabetic patients had a high prevalence of nonsegmentaldistribution (27%) and multiple small cavities within any given lesion (30%),"tree-in-bud" appearance (43%), bronchiectasis (30%). Ground-glass pattern wasnoticed5times before treatment,5times after3month treatment and3times after6month treatment. Centrilobular nodules and poorly marginated nodules, reticular pattern(intralobular and septal thickening), interstitial nodules, and fibrosis were seen bothbefore and after treatment. Unusual localization of tuberculosis, including diseaseconfined to the basal segments of the lower lobes, anterior segment of the upper lobes,or right middle lobe, occurred equally in both groups. CONCLUSION: CT findings of tuberculosis in diabetic patients differ from thosein non-diabetic patients. Diabetic patients with tuberculosis have a higher prevalence ofnonsegmental distribution and of multiple cavities within a tuberculous lesion than donon-diabetic patients. On follow-up examination the disappearance of “tree-in-bud”appearance, absence of pleural effusion and the presence of fibrotic changes seemed tobe indications of effectiveness of treatment. Diabetes had a negative impact ontreatment outcome and the resolution of lesions on CT in diabetic patients was slowerthan in non-diabetic patients. CT can provide important information in the diagnosis andmanagement of the disease. This is particularly helpful in the early treatment of thediseases, because only half of TB patients had acid fast bacilli present in their sputum.