Cryptococcosis is an infection caused by the fungus Cryptococcus neoformans or Cryptococcus gattii.
- People may have no symptoms or may have headache and confusion, a cough and an achy chest, or a rash, depending on where the infection is.
- The diagnosis is based on culture and examination of tissue and fluid samples.
- Antifungal drugs are given by mouth or, if the infection is severe, intravenously.
(See also Overview of Fungal Infections.)
Cryptococcus neoformans occurs primarily in soil that is contaminated with bird droppings, particularly those of pigeons. It is found all over the world. Cryptococcus gattii usually is present in the soil around trees. Outbreaks have occurred in the Pacific Northwest, Papua New Guinea, northern Australia, and in the Mediterranean region of Europe. Unlike Cryptococcus neoformans, Cryptococcus gattii is not associated with birds.
Cryptococcus infection was relatively rare until the AIDS epidemic began. Cryptococcosis is the most common potentially fatal fungal infection in people with AIDS.
The fungus tends to infect people who have a weakened immune system, including those with the following:
- Hodgkin lymphoma or another lymphoma
- Use of drugs that suppress the immune system, such as those used to prevent rejection of an organ transplant and, when taken for a long time, corticosteroids
However, cryptococcosis caused by Cryptococcus gattii can also develop in people with a normal immune system. It is also more likely to occur in people who have other lung disorders, are 50 years old or older, or smoke tobacco.
Infection usually occurs when people inhale the spores of the fungus. Thus, cryptococcosis typically affects the lungs. It most commonly spreads to the brain and tissues covering the brain and spinal cord (meninges), resulting in meningitis.
Cryptococcosis may also spread to the skin and other tissues, such as the bones, joints, liver, spleen, kidneys, and prostate. Except for skin infections, these infections usually cause few or no symptoms.
Symptoms of Cryptococcosis
Cryptococcosis usually causes mild and vague symptoms. Other symptoms vary depending on where the infection is:
- Lung infection: No symptoms in some people, a cough or an aching chest in others, and, if the infection is severe, difficulty breathing
- Meningitis: Headache, blurred vision, depression, agitation, and confusion
- Skin infection: A rash, consisting of bumps (sometimes filled with pus) or open sores
Lung infection is rarely dangerous. Meningitis is life threatening.
Diagnosis of Cryptococcosis
- Culture and examination of a sample of tissue or fluid
To diagnose cryptococcosis, a doctor takes samples of tissue and body fluids to be cultured and examined. A spinal tap (lumbar puncture) is done to obtain cerebrospinal fluid (the fluid that surrounds the brain and spinal cord).
Blood and cerebrospinal fluid may be tested for certain substances released by Cryptococcus.
Doctors also take a chest x-ray to check for signs of infection in the lungs.
Treatment of Cryptococcosis
- Antifungal drugs
Antifungal drugs are usually used to treat cryptococcosis.
People with a normal immune system
If the infection affects only a small part of lung and does not cause any symptoms, usually no treatment is needed. However, some doctors prefer to always treat cryptococcosis. Fluconazole is given by mouth to shorten the duration of the illness and reduce the risk of the infection spreading.
If a lung infection causes symptoms, fluconazole is given by mouth for 6 to 12 months.
For meningitis, treatment is amphotericin B, given intravenously, plus flucytosine, given by mouth, followed by fluconazole, given by mouth, for many months.
For an infection in the skin, bone, or other sites, people are usually given fluconazole by mouth. If the infection is severe, people are given amphotericin B intravenously, plus flucytosine, given by mouth for several weeks.
People with a weakened immune system
People with a weakened immune system always require treatment.
Mild to moderate lung infection may be treated with fluconazole given by mouth for 6 to 12 months.
Severe lung infection or meningitis may be treated with amphotericin B, given intravenously, plus flucytosine, followed by fluconazole, both given by mouth.
After cryptococcosis is treated, people with AIDS usually need to continue taking an antifungal drug (such as fluconazole) until their CD4 count (the number of one type of white blood cell that decrease when AIDS is uncontrolled) is more than 150 cells per microliter of blood and they have taken antifungal drugs for at least a year.
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