Is it tuberculosis or chronic pulmonary aspergillosis? Diagnostic challenges, consequences of misdiagnosis, and potential solutions in resource-limited settings

SUMMARY

Chronic pulmonary aspergillosis (CPA) is most often caused by Aspergillus fumigatus and carries significant mortality and morbidity. While the diagnosis of CPA is often delayed, the emergence of CPA among patients with a concurrent or previous history of mycobacterial disease presents a challenge for CPA diagnosis. When patients previously treated for mycobacterial diseases present with new symptoms, it is often unclear whether these symptoms are due to a recurrence of pulmonary tuberculosis (PTB), non-tuberculous mycobacteria (NTM) infection, CPA, co-infection, or another of several other differential diagnoses. Consequently, PTB patients can be misdiagnosed as having smear/GeneXpert-negative PTB. We address these challenges, given the different associated mortality and morbidity of NTM, PTB, and CPA. We proposed a new algorithm to guide clinicians in ruling CPA in or out in both newly diagnosed smear/GeneXpert-negative and NTM patients and those with a previous history of mycobacterial disease. We also recommend follow-up screening of those with a high risk of developing CPA following their PTB/NTM treatment. Implementing screening strategies, such as performing end-of-treatment TB chest X-rays and Aspergillus -specific IgG tests during and at the end of mycobacterial therapy, could facilitate the early diagnosis and treatment of CPA and alleviate associated mortality and morbidity.