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Coccidioidomycosis (+)k@k-+si-dE-+oi-dO-(+)mI-!kO-sus

by Alan M. Sugar, MD

Coccidioidomycosis (San Joaquin fever, valley fever) is infection, usually of the lungs, caused by the fungus Coccidioides immitis.

  • The infection is caused by inhaling spores of the fungus.

  • If mild, the lung infection causes flu-like symptoms and sometimes shortness of breath, but the infection may worsen and spread throughout the body, causing various symptoms.

  • The diagnosis can be confirmed by identifying the fungi in samples of infected materials examined under a microscope or cultured.

  • Antifungal drugs, given by mouth or intravenously, must be taken for years, sometimes for life.

The spores of Coccidioides are present in soil in the southwestern United States, Central America, and South America. Farmers and others who work with or are exposed to disturbed soil are most likely to inhale the spores and become infected. People who become infected while traveling may not develop symptoms until after they go home.

Coccidioidomycosis occurs in two forms:

  • Mild lung infection (acute primary coccidioidomycosis): The infection disappears without treatment. It accounts for about half of cases.

  • Severe, progressive infection (progressive coccidioidomycosis): The infection spreads throughout the body and is often fatal. It is more common among men and among blacks, Filipinos, and Native Americans. This form is more likely to occur when the immune system is weakened—by disorders (particularly AIDS) or by drugs that suppress the immune system.

Did You Know...

  • An allergic reaction to the Coccidioides fungus usually means that people are effectively fighting off the infection.

Symptoms

Most people with acute primary coccidioidomycosis have no symptoms. If symptoms develop, they appear 1 to 3 weeks after people are infected. Symptoms are usually mild and often flu-like. They include a cough, fever, chills, chest pain, and sometimes shortness of breath. The cough may produce sputum and occasionally blood. Some people develop desert rheumatism, which includes inflammation of the surface of the eye (conjunctivitis) and joints (arthritis) and formation of skin nodules (erythema nodosum). These effects, which can be painful, are allergic reactions to the fungus and usually imply that people are fighting off the fungus effectively.

The progressive form is uncommon and may develop weeks, months, or even years after the initial infection. Symptoms include mild fever and loss of appetite, weight, and strength. The lung infection may worsen, causing increased shortness of breath. The infection may also spread from the lungs to the bones, joints, liver, spleen, and kidneys. Joints may become swollen and painful. The fungi can also infect the brain and the tissues covering the brain (meninges), causing meningitis. This infection is often chronic, causing headaches, confusion, loss of balance, double vision, and other problems. Untreated meningitis is always fatal.

Diagnosis

A doctor may suspect coccidioidomycosis if people develop symptoms after living in or recently traveling through an area where the infection is common. Chest x-rays usually show abnormalities. But to identify the fungi and thus confirm the diagnosis, doctors may examine samples of blood, sputum, pus, or other infected tissue under a microscope or send them to a laboratory to be cultured.

Treatment

Acute primary coccidioidomycosis typically goes away without treatment, and recovery is usually complete. However, some doctors prefer to treat coccidioidomycosis if it affects the lungs.

For the progressive form, fluconazole is given by mouth, or amphotericin B is given intravenously. Alternatively, the doctor may treat the infection with voriconazole or posaconazole.

If meningitis develops, amphotericin B or fluconazole is given intravenously. In addition, amphotericin B may be injected directly into the spinal fluid.

Although drug treatment can be effective in localized infections (for example, in the skin, bones, or joints), relapses often occur after treatment is stopped. Treatment must therefore be continued for years, often for life.

Allergic symptoms often require treatment, such as corticosteroids.

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