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Coccidioidomycosis

Also known as valley fever and San Joaquin Valley fever, coccidioidomycosis is caused by the fungus Coccidioides immitis. It occurs primarily as a respiratory tract infection, although generalized dissemination may occur.

The primary pulmonary form is usually self-limiting and rarely fatal. The rare secondary (progressive, disseminated) form produces abscesses throughout the body and carries a mortality of up to 60%, even with treatment. Such dissemination is more common in dark skinned men, pregnant women, and patients who are receiving immunosuppressants.

Causes and symptoms

When the spores of C. immitis are inhaled, they can become lodged in the lungs, divide, and cause localized inflammation. This is known as acute or primary coccidioidomycosis. The disease is not spread from one person to another. Approximately 60% of people who are infected exhibit no symptoms (asymptomatic). In the other 40%, symptoms appear 10-30 days after exposure. These symptoms include a fever which can reach 104°F (39.5°C), dry cough , chest pains, joint and muscle aches, headache , and weight loss. About two weeks after the start of the fever, some people develop a painful red rash or lumps on the lower legs. Symptoms usually disappear without treatment in about one month. People who have been infected gain partial immunity to re-infection.

The chronic form of coccidioidomycosis normally occurs after a long latent period of 20 or more years during which the patient experiences no symptoms of the disease. In the chronic phase, coccidioidomycosis causes lung abscesses that rupture, spilling pus and fluid into the lungs, and causing serious damage to the lungs. The patient experiences difficulty breathing and has a fever, chest pain , and other signs of pneumonia . Medical treatment is essential for recovery.

In its disseminated form, coccidioidomycosis spreads to other parts of the body including the liver, bones, skin, brain, heart, and lining around the heart (pericardium). Symptoms include fever, joint pain, loss of appetite, weight loss, night sweats, skin lesions , and difficulty breathing. Also, in 30-50% of patients with disseminated coccidioidomycosis, the tissue coverings of the brain and spinal cord become inflamed ( meningitis ).

Diagnosis

Typical clinical features and skin and serologic studies confirm the diagnosis. The primary form - and sometimes the disseminated form - produces a positive coccidioidin skin test. In the first week of illness, complement fixation for immunoglobulin G antibodies or, in the first month, positive serum precipitins (immunoglobulins) also establish this diagnosis.

Examination or, more recently, immunodiffusion testing of sputum, pus from lesions, and a tissue biopsy may show C. immitis spores. The presence of antibodies in pleural and joint fluid and a rising serum or body fluid antibody titer indicate dissemination.

Other abnormal laboratory results include an increased white blood cell (WBC) count, eosinophilia, increased erythrocyte sedimentation rate, and a chest X-ray showing bilateral diffuse infiltrates.

In coccidioidal meningitis, examination of cerebrospinal fluid shows the WBC count increased to more than 500/111 (primarily because of mononuclear leukocytes) and increased protein and decreased glucose levels. Ventricular fluid obtained from the brain may contain complement fixation antibodies.

After the diagnosis has been reached, the results of serial skin tests, blood cultures, and serologic testing may document the effectiveness of therapy.

Treatment

Usually, mild primary coccidioidomycosis requires only bed rest and relief of symptoms. Severe primary disease and dissemination, however, also require long-term I. V. infusion or, in CNS dissemination, intrathecal administration of amphotericin B and, possibly, excision or drainage of lesions. Severe pulmonary lesions may require lobectomy. Miconazole and ketoconazole suppress C. immitis but don't eradicate it.

Supplements of vitamins C, E, A-plus, and B complex may also be useful. Lactobacillus acidophilus and Bifidobacterium will replenish the good bacteria in the intestines. Antifungal herbs, like garlic ( Allium sativum ), can be consumed in relatively large does and for an extended period of time in order to increase effectiveness.

Prevention

General maintenance of good health will limit the disease to a benign pulmonary form. Prevention of AIDS or other causes of damage to the immune system will generally prevent the more severe forms of the disease.