Aspergillosis is an opportunistic infection caused by fungi of the genus Aspergillus, usually A. fumigatus, A. flavus, and A. niger. It occurs in four major forms: aspergilloma, which produces a fungus ball in the lungs (called a mycetoma); allergic aspergillosis, a hypersensitive asthmatic reaction to aspergillus antigens; aspergillosis endophthalmitis, an infection of the anterior and posterior chambers of the eye that can lead to blindness; and disseminated aspergillosis, an acute infection that produces septicemia, thrombosis, and infarction of virtually any organ, but especially the heart, lungs, brain, and kidneys.
Aspergillus may cause infection of the ear (otomycosis), cornea (mycotic keratitis), and prosthetic heart valves (endocar-ditis); pneumonia (especially in patients receiving immunosuppressants, such as antineoplastic agents or high-dose steroids); sinusitis; and brain abscesses.
The prognosis varies with each form. Occasionally, aspergilloma causes fatal hemoptysis.
Aspergillus is found worldwide, commonly in decaying vegetation, such as fermenting compost piles and damp hay. It's transmitted by inhalation of fungal spores or, in aspergillosis endophthalmitis, by the invasion of spores through a wound or other tissue injury. It's a common laboratory contaminant.
Aspergillus produces clinical infection only in people who become especially vulnerable to it. Such vulnerability can result from excessive or prolonged use of antibiotics, glucocorticoids, or other immunosuppressive agents; from radiation; from such conditions as acquired immunodeficiency syndrome, Hodgkin's disease, leu-kemia, azotemia, alcoholism, sarcoidosis, bronchitis, or bronchiectasis; from organ transplants; and, in aspergilloma, from tuberculosis or another cavitary lung disease.
The incubation period in aspergillosis ranges from a few days to weeks. In aspergilloma, colonization of the bronchial tree with Aspergillus produces plugs and atelectasis and forms a tangled ball of hyphae (fungal filaments), fibrin, and exudate in a cavity left by a previous illness such as tuberculosis. Characteristically, aspergilloma either causes no symptoms or mimics tuberculosis, causing a productive cough and purulent or blood-tinged sputum, dyspnea, empyema, and lung abscesses.
Allergic aspergillosis causes wheezing, dyspnea, cough with some sputum production, pleural pain, and fever.
Aspergillosis endophthalmitis usually appears 2 to 3 weeks after an eye injury or surgery and accounts for half of all cases of endophthalmitis. It causes clouded vision, eye pain, and reddened conjunctiva. Eventually, Aspergillus infects the anterior and posterior chambers, where it produces purulent exudate.
Alert In disseminated aspergillosis, Aspergillus invades blood vessels and causes thrombosis, infarctions, and the typical signs and symptoms of septicemia (chills, fever, hypotension, delirium), with azotemia, hematuria, urinary tract obstruction, headaches, seizures, bone pain and tenderness, and soft-tissue swelling. It's rapidly fatal.
In patients with aspergilloma, a chest X-ray reveals a crescent-shaped radiolucency surrounding a circular mass, but this isn’t definitive for aspergillosis.
CONFIRMING DIAGNOSIS In aspergillosis endophthalmitis, a history of ocular trauma or surgery and a culture or exudate showing Aspergillus is diagnostic. In disseminated aspergillosis, culture and microscopic examination of affected tissue can confirm the diagnosis, but this form is usually diagnosed at autopsy.
In allergic aspergillosis, sputum examination shows eosinophils. Culture of mouth scrapings or sputum showing Aspergillus is inconclusive because even healthy people harbor this fungus.
Aspergillosis doesn’t require isolation. Treatment requires local excision of the lesion and supportive therapy, such as chest physiotherapy and coughing, to improve pulmonary function. Endocarditis caused by Aspergillus is treated by surgical removal of infected heart valves and long-term amphotericin B therapy. Allergic aspergillosis requires desensitization and, possibly, steroids. Disseminated aspergillosis and aspergillosis endophthalmitis require a 2- to 3-week course of I.V. amphotericin B (as well as prompt cessation of immunosuppressive therapy). Voriconazole or itraconazole can also be used for treatment. However, the disseminated form results in an infection that's so virulent that amphotericin B therapy can’t stop the systemic involvement; eventually, death ensues.
❑Assist with chest physiotherapy and instruct the patient to cough effectively.
❑Monitor the patient's vital signs, intake and output, and diagnostic test results.
❑Provide emotional support for the patient and his family.
Review other book chapters online related to Aspergillosis:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Professional Guide to Diseases (Eighth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2005 ISBN: 1-58255-370-X 
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