Tuesday, October 19, 2021
HomeInfectious DiseasesCPA evaluated as an alternative diagnosis of smear-negative TB

CPA evaluated as an alternative diagnosis of smear-negative TB

Patients suspected of having tuberculosis (TB) may generate no sputum, and have smear and/or GeneXpert negative samples, and yet be ill. Only 20–40% of smear negative sputa turn culture positive for M. tuberculosis. Yet clinicians may initiate anti-TB treatment for these patients. TB treatment is onerous and not all patients will respond.

Chronic pulmonary aspergillosis (CPA) is a life-threatening fungal infection that generally occurs concurrently with or following other respiratory diseases, including TB. Diagnosis can be challenging because radiological signs (cavitation, fibrosis) can appear similar for both TB and CPA. Aspergillus fumigatus IgG testing is positive in >90% of CPA patients. Not all pathogenic species of Aspergillus are detected using standard serological (IgG) testing.

In this study, a multicentre survey of patients led by RO Oladele at the College of Medicine, University of Lagos, Lagos, Nigeria and the faculty of biology, medicine and health, University of Manchester, Manchester Academic Health Science Centre, Manchester, was carried out in TB clinics in Lagos and Ilorin states (Nigeria), between June 2014 and May 2015. Patients were either being treated for smear-negative TB or were in their final month of being treated for smear-positive TB. Oladele estimated the prevalence of CPA among Nigerian TB patients as around 9% overall, based on clinical, radiological and either microbiological or serological evidence. Of 208 patients recruited, only around half (52%) had documented TB. 153 patients (74%) were HIV-positive, and the rate of CPA among HIV-positive patients (6.5%) was lower than among HIV-negative patients (14.5%).

Abstract
Objective: To evaluate chronic pulmonary aspergillosis (CPA) as an alternative diagnosis of smear-negative tuberculosis (TB) and treatment failure in TB patients in Nigeria.
Methods: We conducted a cross-sectional multicentre survey in human immunodeficiency virus (HIV) positive and negative adult patients at the end of their TB treatment in clinics in Lagos and Ilorin states. All were assessed using clinical examination, chest X-ray (CXR) and aspergillus immunoglobulin G (IgG) serology, and some for sputum fungal culture. CPA was defined as a positive Aspergillus fumigatus IgG titre with compatible CXR or a positive sputum culture of Aspergillus with a visible fungal ball on CXR with symptoms of underlying lung disease.
Results: Of 208 patients recruited between June 2014 and May 2015, 153 (73.6%) were HIV-positive. The mean age was 39.8 years, 124 (59.6%) were female and 39 (18.8%) were unable to work. The median CD4 count was 169.5 cells/ml (range 4-593) in HIV-infected patients with positive Aspergillus IgG. Overall, 109 (52.4%) had documented TB, 140 (67.3%) had a productive cough and 50 had haemoptysis. CPA prevalence was 8.7%; 10 (6.5%) had HIV infection and 8 (14.5%) were HIV-negative (Fisher's exact P = 0.092).
Conclusion: CPA is a neglected disease in Nigeria, and most cases match the World Health Organization diagnostic criteria for smear-negative TB.

Authors
Oladele RO, Irurhe NK, Foden P, Akanmu AS, Gbaja-Biamila T, Nwosu A, Ekundayo HA, Ogunsola FT, Richardson MD, Denning DW

[link url="http://www.life-worldwide.org/media-centre/article/consider-aspergillosis-as-an-alternate-diagnosis-for-smear-negative-tb-pati"]Life Worldwide material[/link]
[link url="https://www.ncbi.nlm.nih.gov/pubmed/28826456"]International Journal of Tuberculosis Lung Diseases abstract[/link]

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