36-10: Paracoccidioidomycosis (South American Blastomycosis)

Paracoccidioides brasiliensis and Paracoccidioides lutzii infections have been found only in patients who have resided in South or Central America or Mexico. Long asymptomatic periods enable patients to travel far from the endemic areas before developing clinical problems. An acute form of the disease affects predominately younger patients and involves the mononuclear phagocytic system, resulting in progressive lymphadenopathy. A more chronic form affects mostly adult men and predominately involves the lung as well as the skin, mucous membranes, and lymph nodes. Weight loss, pulmonary complaints, or mucosal ulcerations are the most common symptoms. Extensive coalescent ulcerations may eventually result in destruction of the epiglottis, vocal cords, and uvula. Extension to the lips and face may occur. Lymph node enlargement may follow mucocutaneous lesions, eventually ulcerating and forming draining sinuses; in some patients, it is the presenting symptom. Hepatosplenomegaly may be present as well. HIV-infected patients with paracoccidioidomycosis are more likely to have extrapulmonary dissemination and a more rapid clinical disease course.

Laboratory findings are nonspecific. Serology by immunodiffusion is positive in more than 80% of cases, although, at present, there are no commercially available assays. Complement fixation titers correlate with progressive disease and fall with effective therapy. The fungus is found in clinical specimens as a spherical cell that may have many buds arising from it. If direct examination of secretions does not reveal the organism, biopsy with Gomori silver staining may be helpful.

Itraconazole, 100 mg twice daily orally, is the treatment of choice and generally results in a clinical response within 1 month and effective control after 2–6 months. TMP-SMZ (480 mg/1200 mg) twice daily orally is equally effective and less costly but associated with more adverse effects and longer time to clinical cure. Voriconazole, 200 mg twice daily orally, appears to be as effective as itraconazole. Amphotericin B, 0.7–1.0 mg/kg/day intravenously, is the medication of choice for severe and life-threatening infection. Amphotericin B lipid complex or liposomal amphotericin B, 3–5 mg/kg/day, is effective and safe for severe disease.

Respiratory sequelae following pulmonary infection is common and correlates with the degree of lung involvement at diagnosis. Relapses following therapy can occur in up to 5% of patients.