fungus 5 Flashcards
inhalation of what dust borne spores causes histoplasmosis
histoplasma capsulatum
where is histoplasmosis most common in the US
the Ohio and Mississippi River valleys
what accelerates sporulation of histoplasma in soils
avian or bat guano contamination
what are risk factors for histoplasmosis
- spelunking
- demolishing chicken coops or barns
- exposure to forests with large bird roosts
- farming
- excavation
what ingest and sequester histoplasma within the human immune system
macrophages
how long after exposure to histoplasma does cellular immunity develop
10-14 days
what do macrophages develop histoplasma into in an immunocompetent host
granulomas
how does primary histoplasmosis infection occur
when granuloma formation fails or is overcome by massive inoculum
how does reactivation of histoplasmosis infection occur
occurs when immune system wanes and granulomas dissipate
what are the two clinical presentations of histoplasmosis
- asymptomatic prirmary infection
- acute pulmonary histoplasmosis
- chronic pulmonary histoplasmosis
- disseminated histoplasmosis
how long does it take for an asymptomatic primary infection to resolve?
1 month without any therapy
mediastinal granulomas, pericarditis and rheumatologic syndromes are possible with what type of histoplasmosis
acute pulmonary histoplasmosis
what is the treatment for mild to moderate acute pulmonary histoplasmosis
less than 4 weeks = no therapy
longer than 4 weeks = itraconazole
what is the treatment for moderately severe or severe acute pulmonary histoplasmosis
liposomal amphotericin B
followed by itrasconazole
and methylprednisolone (with inflammation)
what is the treatment of chronic cavitary pulmonary histoplasmosis
itraconazole for 1 year (longer if immunocompromised)
what is the treatment for mild to moderate disseminated histoplasmosis
itraconazole
what is the treatment for moderately severe or severe disseminated histoplasmosis
liposomal amphotericin B (or any other form)
followed by itraconazole
what is the treatment for dissimenated histoplasmosis in the CNS
liposomal amphotericin B
followed by itraconazole (for a year)
what other fungus is very similar to histoplasmosis pathogenically
blastomycosis
what are the different clinical presentations of bastomycosis
- acute pulmonary blastomycosis
- chronic pulmonary blastomycosis
- disseminated/ extrapulmonary blastomycosis
what does chronic pulmonary blastomycosis mimic?
TB
what is the least common but most fatal form of blastomycosis
in the CNS
how are the signs of cryptococcosis different from histoplasmosis and blastomycosis
cryptococcosis symptoms are generally in the CNS; not in the lungs
skin lesions are often seen with what two fungi
histoplasmosis and blastomycosis
True/False severe histoplasmosis and blastomycosis are both treated with liposomal amphotericin followed by itraconazole
true
