San Joaquin Valley fever

Alternative names
Coccidiosis; Coccidioidomycosis; Valley fever

Definition
Coccidiodomycosis is a disease caused by the spores of the fungus, Coccidioides immitis.

Causes, incidence, and risk factors

Infection is caused by inhalation of the spores of the fungus, Coccidioides immitis, which is often found in desert regions. About 60% of infections cause no symptoms and are only recognized later by a positive coccidioidin skin test.

In the remaining 40% of cases, symptoms range from mild to severe. People with a compromised immune system tend to have more serious infections. Individuals with AIDS are at higher risk for pulmonary (lung) coccidioidomycosis, as well as for the disseminated (spread to many body systems) and cutaneous (skin) forms of the disease.

The disease can have an acute, chronic, or disseminated form. Acute pulmonary coccidioidomycosis is almost always mild, with few or no symptoms, and resolves without treatment. The incubation period is 7 to 21 days.

Acute coccidioidomycosis is rare. In any given year, about 3% of people who live in an area where coccidiomycosis is commonly seen will develop the disease.

Chronic pulmonary coccidioidomycosis can develop 20 or more years after initial infection which may not have been recognized, diagnosed, or treated at the time. Infections (lung abscesses) can form and rupture releasing pus (empyema) between the lungs and ribs (pleural space). This disorder is even less common than the acute form, however.

In disseminated disease, spread of infection to the bones, lungs, liver, meninges, brain, skin, heart, and pericardium (sac around the heart) may take place. Meningitis occurs in 30-50% of cases of disseminated disease. The course of the disease may be rapid for immunosuppressed patients.

Symptoms
Any of the following may be symptoms:

     
  • Cough  
  • Chest pain, varies from mild sense of constriction to severe  
  • Fever  
  • Chills  
  • Night sweats  
  • Headache  
  • Muscle stiffness  
  • Muscle aches  
  • Joint stiffness  
  • Neck stiffness or shoulder stiffness  
  • Rash, may be painful, red, on lower legs (erythema nodosum)  
  • Blood-tinged sputum  
  • Loss of appetite  
  • Weight loss  
  • Wheezing  
  • Sweating, excessive  
  • Change in mental status  
  • Sensitivity to light

Additional symptoms that may be associated with this disease:

     
  • Joint swelling  
  • Joint pain  
  • Arthritis  
  • Ankle, feet, and leg swelling

See also skin lesion of coccidioidomycosis.

Signs and tests

     
  • Sputum smear (KOH test)  
  • Sputum culture  
  • Serum coccidioides complement fixation titer  
  • CBC with differential shows elevated eosinophils  
  • Chest X-ray  
  • Coccidioidin or spherulin skin test

Treatment

The acute disease almost always goes away without treatment. Bedrest and treatment of flu-like symptoms until fever disappears may be recommended.

Disseminated or severe disease should be treated with amphotericin B, ketoconazole, fluconazole, or itraconazole.

Expectations (prognosis)
The outcome in acute disease is likely to be good. With treatment, for chronic or severe disease, the outcome is usually good (although relapses may occur). People with disseminated disease have a high death rate.

Complications

     
  • Pleural effusion  
  • Relapse of infection  
  • Spread of the infection throughout the body  
  • Complications from medications. In particular, amphotericin B may cause fever, chills, and nausea while it is being given, and may cause abnormal kidney tests after many doses.

Calling your health care provider
Call for an appointment with your health care provider if symptoms develop that are suggestive of coccidioidomycosis.

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.

Johns Hopkins patient information

Last revised: December 3, 2012
by Gevorg A. Poghosian, Ph.D.

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