Clinical spectrum and treatment of classic histoplasmosis
Unidad Micología, Hospital de Infecciosas Francisco Javier Muñiz, Buenos Aires, Argentina
Primary lung infection is seen in immunocompetent hosts. Beside the respiratory symptoms, the infection produces various manifestations resulting from hypersensitivity to causal agent antigens, characterized by erythema nodosum, arthritis, pleuresy and pericarditis; alterations resulting from the invasion of mediastinal lymph nodes; and histoplasmomas. The chronic, cavitary form of pulmonary histoplasmosis occurs in males, older than 50 years of age, with chronic obstructive bronchopulmonary disease.
The disseminated, progressive forms of the disease are produced in persons with defective cell-mediated immunity. These evolve more rapidly and tend to be more serious, depending on the severity of the host's immunosupression. Over the past years, organ transplants, lymphoma chemotherapy and the AIDS pandemic have contributed importantly to the increase in the acute and subacute forms of disseminated histoplasmosis. Focal lesions, especially mucocutaneous ulcers, predominate in the chronic, disseminated forms of the disease. The predominant clinical manifestations of the acute and subacute forms resemble those of a grave infectious process and include fever, weight loss, hepatosplenomegaly, micronodular interstitial lung infiltrates, generalized adenopathies, diarrhea and cytopenia. Fulminant cases present respiratory distress, shock, disseminated intravascular coagulation and multi-organ failure.
Currently, itraconazole and amphotericin B are the two drugs most frequently employed to combat this disease. These two antifungal agents are generally used for the chronic pulmonary and disseminated forms of histoplasmosis. Amphotericin B is usually reserved for the most serious cases or for patients receiving other drugs which interact with itraconazole.
A preventive vaccine is not currently available. Primary prophylaxis treatment for high-risk patients has not been universally accepted.
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