Chapter 6--paracoccidioidomycosis

Abstract

Paracoccidioidomycosis is a systemic mycosis caused by the dimorphic fungus Paracoccidioides brasiliensis. The disease is restricted to Latin America. It is the principal systemic mycosis in Brazil, with higher incidences in the southern, southeastern and central regions. The disease is acquired by inhaling fungal propagules. In endemic areas, the primary infection occurs during childhood and involves the immune system. The most common chronic form of paracoccidioidomycosis in adults is the multifocal form, in which there is dissemination to the lungs, lymph nodes, skin and mucosae. This form of the disease has a chronic progression, and the diagnosis is typically delayed. Cough, dyspnea and weight loss due to cutaneous and mucosal lesions are evident and are the principal complaints reported by paracoccidioidomycosis patients. Chest X-rays reveal diffuse reticulonodular infiltrates, which are more evident in the upper lobes. The etiologic diagnosis is based on the identification of P. brasiliensis in clinical specimens, such as lymph node aspirates or BAL fluid, by direct microscopy and culture. Histopathological testing of tissue samples reveals the thick birefringent cell wall of the fungus and the typical pattern of multiple budding around the mother cell. Double agar gel immunodiffusion is useful for the diagnosis when the fungus cannot be detected through mycological tests. Although paracoccidioidomycosis is most often treated with the sulfamethoxazole-trimethoprim combination, itraconazole is preferable. Amphotericin B is used in severe cases.