Fungal infections

Question 1

characteristics of fungi

Answer 1

nonmotile eukaryotes without chlorophyll and with a rigid cell wall

Question 2

yeast. definition and pathogens

Answer 2

fungus growing as a round or oval uncellular oganism that reproduces by budding or fission candida and cryptococcus neoformans.

Question 3

mold. definitions and pathogens.

Answer 3

fungus growing in hyphal form reproducing by sexual or asexual spore formation. aspergillis, dermatophytes, mucoromycosis

Question 4

dimorphic

Answer 4

fungi that go between yeast and mold forms- usually yeast in body and mold in culture. histoplasmosis, blastomycosis, coccidiodomycosis, malassezia furfur, sporotrichosis

Question 5

dermatophytes

Answer 5

tinea corporis (ring worm), tinea pedis (athlete’s foot), tinea cruris (jock itch), tinea capitis (scalp and hair), onychomycosis

Question 6

treatment of onychomycosis and tinea capitis

Answer 6

terbinafine or oral azoles

Question 7

diagnosis of dermatophytes

Answer 7

may be done by looking at affected area, or using KOH prep/culture

Question 8

Pityriasis versicolor

Answer 8

dimorphic Malassezia furfur. yeast are lipophilic and part of normal skin flora, but can proliferate in the setting of lipids and sweat to produce hypo and hyperpigmented tesions on the back and chest. May cause blood infections. May also be associated with total parenteral nutrition.

Question 9

pityriasis versicolor treatment

Answer 9

oral keoconazole, fluconazole, or itraconazole. topical selenium.

Question 10

Sporotrichosis

Answer 10

dimorphic fungus found in soil. usuall inoculated through thorns. infection spreads through the draining lymhatics: mixed pyogenic and granlomatous rxn. May extend to bone in very rare cases. itraconazole unless in bone- then use amphotericin

Question 11

chromoblastomycosis

Answer 11

in tropical and subtropical areas. gets through small cuts. you’ll see Medlar bodies (globe shaped cigar colored thick walled structures). May spread to healthy skin. Lymphatic and cutaneous spread possible. treatment involves combo of surgery, heat, and antifungals. granulomas around typical sclerotic cells. ITRACONAZOLE, TERBINAFINE, AND POSACONAZOLE

Question 12

coccidiomycosis: fungus type, location, lifecycle, outcomes

Answer 12

dimorphic fungus. grows as yeast in body. seen hot arid areas (SW of US). spores inahled into the lung. swell into spherules packed with endospores. Spheroids burst- endospores released. consolidation, caseation, necrosis, cavity, nodule formation. Infection often contained, some will get Valley Fever (pulmonary infection, fever, cough, rash), some may get sick from latent, walled-off disease.

Question 13

coccidiomycosis: complications

Answer 13

meninges, chronic meningitis, transverse myelitis, osteolytic lesions, liver, spleen.

Question 14

coccidomycosis: diagnosis

Answer 14

urinary antigen test, path, antibody tests

Question 15

coccidiomycosis treatment

Answer 15

non for immunocompetent; treat with itraconazole, fluconazole, or voriconazole in ppl with diseeminated disease and immunocompromised including pregnant women for the last month. for really sever cases amphotericin b

Question 16

histoplasmos

Answer 16

Ohio, Mississppi, and missouri, great lakes. Soil and bat droppings. only become pathogenic after ingestion by macrophages in the lung. usually forms granulomas that can be ssen in CSR.

Question 17

histoplasmosis complications. Dx,

Answer 17

disseminated spread to skin, tongu, cns, liver, spleen, eye.

diagnosis by urine antigen, serum antibody. better than cuture

Question 18

histoplasmosis treatment

Answer 18

none if less than 4 wks mild infection. itraconazole if more than 4 wks. amphotericin B if severe with cns involvement

Question 19

blastomycis

Answer 19

humid wooded areas of northa america. beaver dam viewing. dissemination via macrophages to the skin, bone, and urinary tract.