Aspergillosis

Aspergillosis

Caused by species of Aspergillus, especially Aspergillus fumigatus – Additional important species include A. flavus, A. niger, and A. terreus. Aspergillus* forms hyaline molds with abundant conidia production. – Conidia are the asexual spores that are ubiquitous in our environment, both outside and inside, including hospitals. – We are constantly inhaling these spores, which, in the immunocompetent, are typically harmless.

Spores can colonize and/or invade individuals who have immune abnormalities.

Hypersensitivity, i.e., allergic reactions to Aspergillus:*

Allergic Aspergillus sinusitis* is a form of chronic rhinosinusitis that can obstruct the sinuses and produce asymmetrical swelling around the orbit and/or nasal sinuses.

Allergic bronchopulmonary aspergillosis occurs in patients with asthma and cystic fibrosis.

– In these individuals, the fungi colonize the bronchopulmonary tissue. – This can lead to obstruction or, upon damage to the vasculature, hemoptysis (coughing up blood).

Because allergic sinusitis and bronchopulmonary aspergillosis are the result of hypersensitivity reactions, corticosteroids are often recommended.

Underlying chronic pulmonary illnesses and/or immunosuppression: Aspergillosis can take a variety of forms:

Aspergillomas, aka, fungus balls (or mycetomas), can form within pre-existing cavities within the lungs or sinuses.

– For example, in a patient with a history of tuberculosis, fungal balls can form within cavities produced by TB infection. – These masses comprise fungal hyphae as well as tissue debris and inflammatory cells.

Chronic pulmonary aspergillosis occurs in patients with chronic lung disease.

– In these individuals, localized lung tissue invasion occurs, which can lead to cavitation with or without formation of fungal balls, or even fibrosis.

Invasive aspergillosis occurs in patients with severe immunodeficiency, and, because of the invasive nature, has a high mortality rate.

– In addition to pulmonary tissue invasion and destruction, the fungus may disseminate to other organs and cause invasive damage.

Aspergillosis can also be a cutaneous mycosis, typically following a wound.

Aspergillosis

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