“Allergic bronchopulmonary aspergillosis misdiagnosed as smear negative pulmonary tuberculosis; a retrospective study from Pakistan”

BACKGROUND: Undiagnosed allergic bronchopulmonary aspergillosis (ABPA) can lead to chronic persistent symptoms. In country like Pakistan where tuberculosis (TB) is endemic, a significant proportion of ABPA patients are misdiagnosed as smear negative TB before reaching a diagnosis of ABPA due to chronicity of symptoms.This lead to empiric use of ATT(Anti-tuberculous therapy) and delay in primary diagnosis. The aim of the study is to determine such proportion of ABPA patients. MATERIAL AND METHODS: This retrospective study was conducted at the outpatient pulmonology clinic of a tertiary care hospital in Karachi, Pakistan from January 2017 to December 2018. Xpert MTB/Rif, TB smear and culture were performed in all patients to rule out active TB. RESULTS: A total 167 of ABPA patients were included. Mean age of the patients was 41.9 ± 13.0 years, 91(54.5%) were female and 71 (42.5%) patients had received ATT in past. Out of these 71 patients, 63 (88.7%) patients were diagnosed as smear negative TB and received empiric ATT. Among 63 patients, 52 (82.5%) patient had received ATT once, 8 (12.6%) twice and 3 (4.7%) patients had received empiric ATT thrice. Of these 27 (16.16%) patients had already developed long term complications at the time of diagnosis of ABPA and 17 (62.96%) patients were in empiric TB treatment group. CONCLUSION: Patient with ABPA frequently received empiric ATT as smear negative TB in high TB burden country. This results in over diagnosis of TB and unnecessary use of global resource. When Gene Xpert negative alternate diagnosis should be considered.