Fungi

Question 1

Superficial infection, associated with outside work in warm, damp climates, causes hypopigmented spots on chest and back and KOH mount shows spaghetti and meatballs

Answer 1

Malassezia furfur, causing pityriasis or tinea versicolor

Question 2

Cutaneous fungal infection that presents with scaly, pruritic ring-like lesions of skin involving hair shaft or nails, KOH shows arthroconidia and hyphae

Answer 2

Dermatophytes - aka “tineas” even though no roundworm is involved

Trichophyton (skin, hair, nails); microsporum (hair, skin); epidermophyton (nails, skin)

Question 3

Treatment of Tineas

Answer 3

Topical imidazoles or tolnaftate and keep area dry

Question 4

Subcutaneous dimorphic fungi, cigar shaped yeast in tissue, associated with traumatic implantation from roses, treat with itraconazole or amphotericin B

Answer 4

Sportothrix schenckii, causing Sporotrichosis (rose gardener disease) or Pulmonary sporotrichosis (alcoholic rose garden sleeper disease)

Question 5

4 dimorphic fungi?

Answer 5

Blastomyces, histoplasma, coccidioides, sporothrix (Mnemonic: Body Heat Changes Shape)

Question 6

Differentiate between histoplasm, coccidioides, and blastomyces based on geography

Answer 6

Histo: Eastern Great Lakes, Ohio, down the Mississippi River, Missouri

Coccidio: SW US

Blasto: Similar to histo, but involves additional spread more North and East (esp N and S Carolina)

Question 7

Hyphae with microconidia and tuberculate macroconidia, exposure to bird or bat droppings (spelunker), facultative intracellular parasite found in reticuloendothelial cells, looks like pnemonia with flu symptoms and hepatosplenomegaly, doesn’t respond to antibiotics

Answer 7

Histoplasma capsulatum (don’t be fooled by the name - there is no capsule!)

Question 8

Hyphae that break into arthroconidia, found in desert sand, inhaled to cause Valley Fever, will see desert bumps (erythema nodosum) and arthritis, pulmonary lesions will calcify, tends to disseminate in third trimester

Answer 8

Coccidioides immitis

Question 9

Hyphae associated with rotting wood, broad based budding yeast with double refractile cell wall, less likely to self-resolve

Answer 9

Blastomyces dermatitidis

Question 10

Dichotomously branching septate hyphae with 45 degree angles, opportunistic and can cause allergic bronchopulmonary reaction in patients with asthma or CF, fungus ball, or invasive disease in severely immunocompromised

Answer 10

Aspergillus fumigatus

Question 11

Normal flora yeast that forms pseudohyphae and true hyphae, associated with cottage cheese discharge and can cause a variety of issues especially in the context of immune compromised or overuse of antibiotics

Answer 11

Candida albicans

Question 12

Encapsulated yeast classically from pigeon droppings, most common meningitis in AIDS patients, urease positive, India ink mount

Answer 12

Cryptococcus neoformans

Question 13

Ribbon like hyphae that branches at 90 degrees, associated with ketoacidotic or leukemic patients, dark colored or black pus, high fatality rate due to rapid growth and progression

Answer 13

Mucor, Rhizopus, Absidia

Question 14

Silver staining cysts, obligate intracellular parasite, foamy or honeycomb appearance on H&E, causes interstitial pneumonia with patchy ground glass infiltrate

Answer 14

Pneumocystis jirovecii