Factors associated with atypical radiological findings of pulmonary tuberculosis.

Background: Unusual radiological images may delay diagnosis of pulmonary tuberculosis. This study aimed to analyze the risk factors for an atypical radiological image in patients with pulmonary tuberculosis.

Methods: We retrospectively analyzed data from patients admitted to one hospital from January 2013 to December 2016 for sputum smear-positive lung tuberculosis who underwent chest computed tomography (CT) on admission. Patients whose sputum cultures were positive for general bacteria were excluded. Patient characteristics and laboratory data were compared between patients with cavity and those without and between patients with upper predominant lung involvement and those without.

Results: This study included 94 (93%) of 101 patients who underwent chest CT. The non-cavity group was older, had a greater number of females, had a lower C-reactive protein (CRP) level, and had a lower glomerular filtration rate. Multivariate analysis showed that a low CRP level (OR 0.808; 95% CI 0.674-0.967; p = 0.020) significantly predicted non-cavity pulmonary tuberculosis. The non-upper predominant lung involvement group was older and had a greater number of females, poorer performance status, a higher CRP level, and a lower serum albumin level. A poor performance status (OR 2.155; 95% CI 1.257-3.693; p = 0.005) was found to significantly predict pulmonary tuberculosis with non-upper predominant lung distributions.

Conclusions: A low CRP level and poor performance status were associated with non-cavity and non-upper predominant lung distribution, respectively, in patients with pulmonary tuberculosis. Tuberculosis patients with these characteristics may present unusual chest images.