micro: mycology

Question 1

histoplasmosis

Answer 1

histo hides (w/in macrophages - smaller than RBC). bird or bat droppings in MI/OH river valleys. -> pna

Question 2

bastomycosis

Answer 2

blasto buds broadly: same size as RBC. eastern US, central america. -> inflam lung dz, can disseminate to skin + bone. -> granulomatous nodules

Question 3

cocciciodomycosis

Answer 3

coccicio crowds: spherule (much > RBC) filled w/endospores. san joaquin valley fever -> desert bumps = erythema nodosum + desert rheumatis = arthralgias. -> pna + meningitis, can -> bone + skin. rate inc. after earthquakes.

Question 4

systemic mycoses

Answer 4

can cause pna, can disseminate. cold = mold, hEAt = yEAst (except coccidio = spherule). Tx: fluconazole or itraconazole for local, ampho B for systemic. systemic mimics TB but w/o person to person transmission

Question 5

paracoccidioidomycosis

Answer 5

paracoccidio parasails with the captain’s wheel all the way to latin america: budding yeast w/captain’s wheel formation = much > RBC

Question 6

tinea

Answer 6

name for dermatophyte (cutaneous fungal) infxns: microsporum, trichophyton, epidermophyton. branching setate hyphae visible on KOH prep w/blue fungal stain

Question 7

tinea capitis

Answer 7

occurs on head, scalp. associated w/LAD, alopecia, scaling

Question 8

tinea corporis

Answer 8

occurs on body. characterized by erythematous scaling rings (ringworm) and central clearing. can be acquired from contact w/infected cat or dog.

Question 9

tinea cruris

Answer 9

occurs in inguinal area. usually does not show central clearing as in tinea corporis

Question 10

tinea pedis

Answer 10

3 varieties: interdigital: most common, moccasin distribution, vesicular type.

Question 11

tinea unguium

Answer 11

onchymycosis, occurs on nails

Question 12

tinea versicolor

Answer 12

cause: malassezia spp: yeast-like but not a dermatophyte. degradation of lipids -> acids -> melanocyte damage -> hypopigmented and/or pink patches. common in summer. spaghetti and meatballs microscopy. Tx: topical and/or oral antifungals, selenium sulfide

Question 13

candida albicans Tx

Answer 13

topical azole for vaginal; mystatin, fluconazole, or caspofungin for oral/esophageal; fluconazole, caspo, or ampho B for systemic

Question 14

aspergillus

Answer 14

likes immunocompromised and chronic granulomatous dz. -> allergic brochopulm aspergillosis (ABPA): associated w/asthma + CF; may -> bronchiectasis + eosinophilia. aspergillomas in lungs, particularly after TB. some species produce aflatoxins -> HCC. A for Acute Angles! not dimorphic

Question 15

mucor + rhizopus

Answer 15

DKA and/or neutropenic pts (e.g. leukemia). fungi proliferate in blood vessel walls, penetrate cribriform plate, enter brain. rhinocerebral, frontal lobe abscess; cavernous sinus thrombosis. h/a, facial pain, black necrotic eschar on face; may have CN involvement. Tx: debridement, ampho B. wide angles

Question 16

crypotoccus

Answer 16

-> meningitis, cryptococcosis. heavily encapsulated yeast. not dimorphic. found in soil, pigeon droppings. acquired through inhalation w/hematogenous dissemination. Cx on Sabouraud agar. stains w/india ink and mucicarmine. latex agglutination test detects polysaccharide capsular Ag: more specific. “soap bubble” brain lesions

Question 17

pneumocystis jirovecii

Answer 17

-> PCP. yeast-like. inhaled. mostly w/o Sx. diffuse, b/l ground-glass opacities on CXR/CT. Dx by Bx or lavage. disc-shaped yeast on methenamine silver stain of lung tissue. Tx/PPx: TMP-SMX, pentamidine, dapsone (prophylaxis only), atovaquone (PPx only). start PPx when CD4+ <200.

Question 18

sporothrix schenckii

Answer 18

dimorphic, cigar-shaped budding yeast that lives on vegetation. spores are traumatically introduced into skin, typically by a thorn (rose-gardeners dz) -> local pustule or ulcer w/nodules along draining lymphatics -> ascending lymphangitis. disseminated dz in immunocompromised. Tx: itraconazole or potassium iodide.