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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:
– 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.
Image Credits: “Sources of Aspergillosis | | Aspergillosis | Types of Fungal Diseases | Fungal Diseases | CDC,” October 12, 2017. https://www.cdc.gov/fungal/diseases/aspergillosis/causes.html.

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