Spectrum of aspergillosis: Pathogenesis, risk factors and management

Abstract

This article reviews comprehensively the spectrum of diseases (aspergillosis) caused by Aspergillus spp, the commonest pathogenic form being the A.fumigatus. Aspergilus spp are ubiguitous in the environment and the respiratory tract is the portal of entry in most cases. Aspergillosis is associated with significant mortality and morbidity, the prevalence appears to be on the increase. About 10million people are at risk of aspergillosis, and 50% would die even with treatment. Immunodeficiency, especially neutropenia is central to the pathogenesis of aspergillosis. Diseases caused by A. fumigatus include;1) Invasive aspergillosis seen mostly in stem cell and organ transplant recipients, patients with haematological malignancies, cancer patients on chemotherapy and patients with AIDS. Invasive aspergillosis is life threatening, it affects the lungs and sinuses but could disseminate to affect the CNS, eye, skin and kidney. 2) Chronic pulmonary Aspergillosis occurs in the setting of previous cavitatry lung disease, most commonly tuberculous infections. 3) Allergic bronchopulmonary aspergillosis (ABPA) affects people with asthma and cystic fibrosis. A. fumigatus is also implicated in the exacerbation of asthma. The clinical symptoms of aspergillosis depend on the type and the systems affected; respiratory symptoms are more common as the respiratory tract is disproportionately affected in aspergillosis. Diagnostic features and treatment also depends on the type of aspergillosis. Diagnostic testing for aspergillosis includes radiologic tests, culture tests, galactomannan testing in body fluids, immunologic tests to detectAspergilus -specific immunoglobulins. Treatment modalities include surgery, use of antifungals and immunomodulatory therapy with cytokines.