Smear-positive pulmonary tuberculosis patients with previously abnormal chest radiographs: missed opportunities for early diagnosis.

Introduction: It is vital to diagnose and treat pulmonary tuberculosis (PTB) early, in the interests of the patient and public health. At the Singapore Tuberculosis Control Unit (TBCU), it was not uncommon to discover abnormal chest radiographs (CXRs) predating their PTB diagnosis by months to years in the electronic medical records (EMRs) of sputum acid-fast bacilli smear-positive patients. Our study explored this observation.

Methods: The EMRs of sputum smear-positive PTB patients treated at the TBCU from January to July 2014 were viewed for abnormal CXRs preceding their PTB diagnosis. Information in the EMRs pertaining to the indication for the CXRs, radiological reports (including whether the possibility of PTB was stated) and action taken was captured.

Results: Of the 254 sputum smear-positive patients, 108 had previous CXRs in their EMRs, of whom 39 (36.1%) had previous CXRs compatible with PTB. Most of these were performed in tertiary institutions and for reasons unrelated to PTB. No action was taken in response to these CXRs in 24 (61.5%) patients. 27 (69.2%) patients had abnormal CXRs dating back more than six months, with 12 (30.8%) dating back more than 30 months before the PTB diagnosis. Patients aged ≥ 55 years were significantly more likely to have previous CXRs that were compatible with PTB.

Conclusion: PTB patients may be asymptomatic or have chronic indolent disease and remain undiagnosed for years. There is a need for vigilance within our healthcare system to seize opportunities for early diagnosis and treatment to prevent the spread of this infectious disease in Singapore.