Chapter 2: coccidioidomycosis

Coccidioidomycosis is a systemic mycosis caused by the dimorphic fungi Coccidioides immitis and Coccidioides posadasii. Infection is acquired by inhalation of infective arthroconidia that live in the soil. In 60% of cases, the infection is benign and resolves spontaneously. In the northern hemisphere, coccidioidomycosis is endemic to arid and semi-arid regions at latitudes between 40 degrees N and 40 degrees S, particularly in the southwestern United States and in northern Mexico. In the semi-arid northeastern region of Brazil, cases of coccidioidomycosis have recently been reported in four states: Piauí (100 cases); Ceará (20 cases); Maranhão (6 cases); and Bahia (2 cases). The illness manifests in one of three clinical forms: the primary pulmonary form; the progressive pulmonary form; or the disseminated form. On average, the symptoms of respiratory infection appear 10 days after exposure. The diagnosis is made by the isolation of Coccidioides sp. in culture or by positive results from smear microscopy (10% potassium hydroxide test), periodic acid-Schiff staining or silver staining of any suspect material (sputum, cerebrospinal fluid, skin exudate, lymph node aspirate, etc.) Agar gel immunodiffusion is the diagnostic test most widely used. The most common finding on X-rays and CT scans is diffuse distribution of multiple pulmonary nodules, most of which are cavitated. The recommended treatment is fluconazole or itraconazole, the mean dose ranging from 200 to 400 mg/day, although as much as 1,200 mg/day is used in certain cases. In severe cases, amphotericin B can be the drug of choice. In cases of neurological involvement, the recommended treatment is administration of fluconazole, at a minimum dose of 400 mg/day.