Seminars in respiratory and critical care medicine
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Pneumocystis (carinii) jiroveci pneumonia can occur in immunocompromised individuals, especially hematopoietic stem and solid organ transplant recipients and those receiving immunosuppressive agents, and is the most common opportunistic infection in persons with advanced human immunodeficiency virus (HIV) infection. The Pneumocystis genus was initially mistaken as a trypanosome and later as a protozoan. Genetic analysis identified the organism as a unicellular fungus. ⋯ Fulminant respiratory failure associated with fever and dry cough is typical in non-HIV-infected patients. Definitive diagnosis relies on histopathological testing of sputum, induced or sampled by fiberoptic bronchoscopy with bronchoalveolar lavage. The first-line drug for treatment and prevention is trimethoprim-sulfamethoxazole.
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Mucormycosis (formerly zygomycosis) is a life-threatening opportunistic mycosis that infects a broad range of hosts with qualitative or quantitative defects in innate immunity, including patients with severe neutropenia, recipients of corticosteroids or other immunosuppressive medications, poorly controlled diabetes mellitus, and those with iron overload states. Mucormycosis has recently emerged as breakthrough sinopulmonary infection in hematologic patients and recipients of transplantation being on antifungal prophylaxis with Aspergillus-active antifungals that lack activity against Mucorales. ⋯ Recent evidence suggests a critical role for iron metabolism and fungal-endothelial cell interactions in pathogenesis of mucormycosis, and holds promise for development of novel therapeutic strategies. Currently, prompt initiation of antifungal therapy with a lipid amphotericin B-based regimen, reversal of underlying host factors, and aggressive surgical approach offers the best chances for survival of patients infected with this devastating mycosis.
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Blastomyces dermatitidis is acquired in almost all cases via inhalation, and pulmonary disease is the most frequent clinical manifestation of blastomycosis. Pulmonary disease can range from asymptomatic infection to rapidly severe and fatal disease. Most cases will present as pneumonia, either acute or chronic, or as a lung mass. ⋯ Detection of urinary Blastomyces antigen is a recent addition to diagnostic options. Itraconazole is the drug of choice for most forms of the disease; amphotericin B is reserved for the more severe forms. Newer azoles such as voriconazole and posaconazole have a limited role in the treatment of pulmonary blastomycosis.
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Cryptococcosis is an invasive fungal infection (IFI), caused predominantly by Cryptococcus neoformans or Cryptococcus gattii, that affects both immunocompromised (IC) and non-IC patients. Although the most serious disease manifestation is meningoencephalitis, cryptococcal pneumonia is underdiagnosed and may disseminate to the central nervous system (CNS) and other sites depending upon host defenses and administration of appropriate antifungal therapy. ⋯ Treatment recommendations include induction therapy with an amphotericin B preparation and flucytosine for IC patients and those with severe disease and fluconazole for mild-to-moderate, localized disease. Knowledge of the pathophysiology, epidemiology, clinical presentation, and treatment of pulmonary cryptococcosis may lead to greater recognition of this underdiagnosed IFI and improved outcomes.