Aspergillosis
Aspergillosis is infection caused by the fungus Aspergillus that usually affects the lungs.
Aspergillus is very common and is frequently found in compost heaps, air vents, and airborne dust. Inhalation of Aspergillus spores is the primary cause of aspergillosis.
Aspergillosis usually affects open spaces in the body, such as cavities that have formed in the lungs from preexisting lung diseases. The infection may also occur in the ear canals and sinuses. In the sinuses and lungs, aspergillosis shows up as a ball (aspergilloma) composed of a tangled mass of fungus fibers, blood clots, and white blood cells. The fungus ball gradually enlarges, destroying lung tissue in the process, but usually does not spread to other areas.
Less often, aspergillosis can become very aggressive and rapidly spread throughout the lungs and often through the bloodstream to the brain and kidneys. This rapid spread occurs mainly in people with a weakened immune system.
In addition to causing infection, Aspergillus sometimes produces an allergic reaction when it is present on a person's skin or mucous membranes (see Section 4, Chapter 51).
Symptoms and Diagnosis
A fungus ball in the lungs may cause no symptoms and may be discovered only with a chest x-ray. Or it may cause repeated coughing up of blood and--rarely--severe, even fatal, bleeding. A rapidly invasive Aspergillus infection in the lungs often causes cough, fever, chest pain, and difficulty breathing.
Aspergillosis affecting the deeper tissues makes a person very ill. Symptoms include fever, chills, shock, delirium, and blood clots. The person may develop kidney failure, liver failure (causing jaundice), and breathing difficulties. Death can occur quickly.
Aspergillosis of the ear canal causes itching and occasionally pain. Fluid draining overnight from the ear may leave a stain on the pillow. Aspergillosis of the sinuses causes a feeling of congestion and sometimes pain or discharge.
In addition to the symptoms, an x-ray or computed tomography (CT) scan of the infected area provides clues for making the diagnosis. Whenever possible, a doctor sends a sample of infected material to a laboratory to confirm identification of the fungus.
Prognosis and Treatment
Aspergillosis that is present only in a sinus or a single spot in the lung progresses slowly. The infection requires treatment but does not pose an immediate danger. However, if the infection is widespread or the person appears seriously ill, treatment is started immediately. Aspergillosis is treated with antifungal drugs, such as amphotericin B, itraconazole, or voriconazole. Some forms of Aspergillus are resistant to these drugs, however, and may need to be treated with a caspofungin, a newer antifungal drug.
Doctors treat aspergillosis in the ear canal by scraping out the fungus and applying drops of antifungal drugs. Fungus collections in the sinuses must usually be removed surgically. If fungus balls in the lungs grow near large blood vessels, they may also need to be removed surgically because they may invade the blood vessel and cause bleeding.
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