Characteristics of Clinical and Radiological Manifestations in Empiric Antibiotic-Delayed Diagnosis of Pulmonary Tuberculosis

Abstract

Background: Delays in the diagnosis of pulmonary tuberculosis (TB) may result in increased patient morbidity and further spread of the disease. Recent published reports suggest that antibiotic treatment might be associated with the delayed diagnosis of TB. The aim of this study was to evaluate the impact of clinical and radiological manifestations in the delayed diagnosis of TB among different antibiotic classes in an endemic TB area.Methods: Patients with culture or tissue biopsy-confirmed TB diagnosed between January 2005 and December 2006 were included and their medical records reviewed and analyzed. Results: Eighty-three of the 403 patients (20.6%) received a fluoroquinolone (FQ group) and 129 (32%) received non-FQ antibiotics (AB group) before the diagnosis of TB. The median duration from initial visit to ordering a TB study was longer in the FQ and AB groups than in the control group (2 and 2 vs. 0 days). More patients in the FQ and AB groups had underlying disease (65.1% and 79.8% vs. 37.2%, respectively), hypoalbuminemia (63.9% and 55.8% vs. 26.2%, respectively) and a positive acid-fast bacilli (AFB) sputum smear (69.9% and 52.7% vs. 49.7%). Specific radiologic patterns and distribution among patients receiving antibiotics, regardless of class, were significantly different from those among patients without antibiotics, and included alveolar consolidation (37.3% vs. 21.9%), multiple lobe infiltrations (50.9% vs. 39.8%) and lower lung involvement (55.2% vs. 31.9%).Conclusion: Patients who received empiric antibiotics before the diagnosis of TB had a higher percentage of underlying diseases, hypoalbuminemia and positive AFB sputum smears. Antibiotic treatment irrespective of class for presumed CAP delayed the diagnosis of pulmonary TB, and the delay was similar regardless of which antibiotic class had been prescribed. The specific radiologic pattern of alveolar consolidation and atypical distribution with multiple lobes and lower lung involvement contributed to masking the underlying pulmonary TB. Clinicians should consider pulmonary TB in their differential diagnosis when prescribing antibiotics for the treatment of CAP, particularly when encountering the specific radiologic features and distribution reported in this study. (Thorac Med 2012; 27: 71-80)