Pathogenesis
Inhaled conidia of Blastomyces are phagocytosed by neutrophils and macrophages in alveoli. Some of these escape phagocytosis and transform into yeast phase rapidly. Having thick walls, these are resistant to phagocytosis. Once they have transitioned to the yeast phase, the Blastomyces cells express the protein BAD-1, which helps the yeast cells attach to host cells, and also impairs activation of immune cells while inhibiting release of tumor necrosis factor. In lung tissue, the cells multiply and may also disseminate through blood and lymphatics to other organs, including the skin, bone, genitourinary tract, and brain. The incubation period for pulmonary blastomycosis is 3 to 15 weeks, although 30–50% of infections are asymptomatic. Diagnosis
Because the symptoms of blastomycosis resemble those of many other conditions, including tuberculosis and lung cancer, diagnosis is often delayed. In 40% of cases, the diagnosis takes more than a month. A rapid diagnosis can however be made based on microscopic examination of sputum samples or samples obtained from a tissue biopsy or bronchoalveolar lavage.Once suspected, the diagnosis of blastomycosis can usually be confirmed by demonstration of the characteristic broad based budding organisms in sputum or tissues by KOH prep, cytology, or histology. Tissue biopsy of skin or other organs may be required in order to diagnose extra-pulmonary disease. Blastomycosis is histologically associated with granulomatous nodules. Commercially available urine antigen testing appears to be quite sensitive in suggesting the diagnosis in cases where the organism is not readily detected.
Peripheral collapses usually involve abnormally low blood pressure and result in collapsed arteries and/or veins, leading to oxygen deprivation to tissues, organs, and limbs.Acute collapse can result from heart failure causing the primary vessels of the heart to collapse, perhaps combined with cardiac arrest. Diagnosis
Treatment
References


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