Does diabetes alter the radiological presentation of pulmonary tuberculosis

The aim of this study is to determine whether diabetes mellitus (DM) alters the radiological manifestations of pulmonary tuberculosis (TB).

A retrospective review of the medical records and skiagrams of 692 consecutive smear positive pulmonary TB patients admitted in the Sahary Chest Hospital, Riyadh, Kingdom of Saudi Arabia, from January 1998 to December 1999, was performed. One hundred and eighty-seven (27%) patients had an associated DM. The radiographic findings of pulmonary TB patients with DM (PTB DM group) were compared to those without DM (PTB group).

The PTB DM group of patients had increased frequency of lung lesions confined to lower lung field compared to PTB group (23.5% versus 2.4%, p<10(-4)). The PTB DM group of patients had significantly higher frequency of cavitary lung lesions compared to PTB group (50.8% versus 39.0%, p=0.005). Also cavitary lesions were more frequently confined to lower lung field in PTB DM group compared to PTB group (28.9% versus 2.5%, p<10(-4)). Logistic regression analysis showed that diabetes was the only independent significant risk factor associated with lung lesions or cavities in the lower lung fields (lung lesions [odds ratio [OD]=12.63, 95% confidence interval [CI]=6.50-24.56]; cavitary lesions [OD=15.66, 95% CI = 5.82-42.16]).

The PTB DM group are more likely to present with atypical radiological images. Among diabetic patients presenting with lower lung field lesions or cavities possibility of TB should always be considered for prompt diagnosis and management.