Systemic Mycoses

Question 1

common features

Answer 1

specific geographic distribution

classic thermal dimorphism

successful response is w/ cell mediated immunity

may become latent TB, forms granuloma

tested w/ skin test DTH

Question 2

valley fever epi

Answer 2

caused by coccidiodies immitis and coccidiodies posadasii

caused by arthroconidia spores- airborne

found in texas, arizona, california, south amareica

Question 3

valley fever pathogenesis

Answer 3

inhaled arthroconidia lodge in alveoli and develop into spherules

rupture of spherules releases endospores that form new spherules

Question 4

valley fever immune response

Answer 4

macrophages and neutrophils

fungi resistant to neutrophils

DTH test indicates protective immune response. otherwise spores will get into blood

Question 5

valley fever clinical features

Answer 5

asymptomatic in many

some- cough, sputum, chest pain, malaise, fever, chills

last 2-6 weeks

can become chronic

in immunocompromised, becomes systemic

Question 6

erythema nodosom

Answer 6

nodules that do not contain organisms and are not indicative of disseminated disease

protective

valley fever

Question 7

valley fever diagnosis

Answer 7

KOH mount

culture on sabourauds agar

serologic test for monitoring progression

DTH

Question 8

histoplasma capsulatum epi

Answer 8

environment form- hyphaaespores- microconidia
grows as yeast

found in Ohio, Mississippi Valley

bird droppings

Question 9

histoplasma capsulatum patho

Answer 9

inhaled spores reach alveoli and germinate in 2-3 days

proliferate in macrophages which migrate to lymph nodes, spleen liver

yeasts increase pH of phagolysosome by producing bicarb and ammonia which allows them to survive

Question 10

histoplasma capsulatum immunity

Answer 10

can infect immune competent individuals and survive inside macrophages or epithelial cells

need cell mediated response and intact immune system to recover
TNF-a and IFN-y are critical

Question 11

histoplasma capsulatum clinical features

Answer 11

histoplasmosis

most infections are asymptomatic

acute pulmonary histoplasmosis is flu-like in immune competent individuals

chronic pulmonary histoplasmosis is opportunistic and can be mistaken for TB

Question 12

histoplasma capsulatum diagnosis

Answer 12

disseminated- wright stained smear of blood

culture

urine Ag test

serologic tests for monitoring disease progression

no skin test

Question 13

blastomyces dermatitidis epi

Answer 13

grows as yeat at 37 with broad base and single buds

may be in mississippi and ohio valley

wooded areas w/ waterways

common in dogs

Question 14

blastomyces dermatitidis pathogenesis

Answer 14

inhalation of spores from soil

spores become yeast which multiply in lung and may desseminate

Bad1 required for virulence, which causes uptake into macrophages

host develops cell mediated immunity- protective- DTH

Question 15

blastomyces dermatitidis immunity

Answer 15

infection causes macrophage and neutrophils to form granuloma. yeast remains resistant to killing

cell mediated immunity is required

Question 16

blastomyces dermatitidis clinical features

Answer 16

may be asymptomatic or produce flu like symptoms

may be self limited or produce chronic disease

Question 17

blastomyces dermatitidis diagnosis

Answer 17

KOH mount with broad based, single buds

Question 18

paracoccidioides braciliensis

Answer 18

comes from south america

thick walled with multiple buds- wagon wheel

disease comes from rural latin america where fungus grows in soil

Question 19

treatment for fungal infection

Answer 19

mild infections can be cured w/o therapy.

more severe- amphotericin B or an azole

immunocompromised pts high risk for reactivation or disseminated disease