fungi

Question 1

What are the anti-fungal agents that act on the cell wall? What is their mechanism of action?

Answer 1

echinocandins - inhibit glucan synthesis

Question 2

What are the anti-fungal agents that act on the cell membrane?

Answer 2

direct damage to cell membrane through pore formation - polyenes (amphotercin B, nystatin)
inhibitors of ergosterol synthesis - azoles

Question 3

what are the anti-fungal agents that act in the nucleus?

Answer 3

flucytosine - inhibits nucleic acid synthesis

griseofluvin - inhibits microtubules/mitosis

Question 4

What are the topical antifungals?

Answer 4

nystatin, clotrimazole, miconazole

Question 5

What anti-fungal agent should you use for fungal nail infections (onychomycosis)?

Answer 5

terbinafine

Question 6

what are the names of the azole drugs?

Answer 6

ketoconazole, fluconazole, itraconazole, voriconazole, posaconazole

Question 7

What are the drugs in the echinocandin family?

Answer 7

caspofungin

Question 8

What are the toxicities related to caspofungin? Amphotericin B?

Answer 8

Caspofungin - infusion related flushing, fever, rash. GI upset. IV site irritation
Amphotericin B - infusion related flushing, fever, rash. Nephrotoxicity with wasting of K+ and Mg2+

Question 9

What are the toxicites related to the azole drugs?

Answer 9

All azoles - elevated LFTs and drug interactions because they interact with cytochrome P450 enzymes
fluconazole - N/V, rash
itraconazole - taste disturbances, osmotic diarrhea, CHF, N/V
voriconazole - visual disturbances
posaconazole - elevated LFTs

Question 10

what are the toxicities related to flucytosine?

Answer 10

bone marrow toxicity, elevated LFTs

Question 11

What are the opportunistic fungi?

Answer 11

candida, cryptococcus neoformans, aspergillus, pneumocystis jiroveci, zygomycetes

Question 12

What are the systemic, endemic dimorphic fungi?

Answer 12

histoplasma capsulatum, blastomycetes dermatitidis, coccidiodes immitis, paracoccidoides brasilensis, penicillium marneffei

Question 13

what are the superficial dermatophytes? subcutaneous mycoses?

Answer 13

trichophyton, malessezia

sporothrix, madurella

Question 14

What are the 3 main clinical manifestations of candida albicans?

Answer 14

cutaneous - diaper rash, skin infections in intertriginous areas, nail plate
mucosal - oral thrush, esopgagitis, vulvovaginal
systemic/disseminated

Question 15

What are the main clinical manifestations of cryptococcus neoformans?

Answer 15

asymptomatic, meningitis, pneumonia, skin lesions [cryptic MAPS]

Question 16

How do you diagnose cryptococcus neoformans?

Answer 16

capsular antigen test, latex agglutination test, India ink stain, culture and stain with PAS and silver stain

Question 17

How do you treat cryptococcal meningitis? Pulmonary cryptococcus?

Answer 17

meningitis - amphotericin B +/- flucytosine, maintenance with fluconazole
pulmonary cryptococcus - fluconazole

Question 18

How does crytococcus avoid the immune system/virulence factors?

Answer 18

capsule, phenotypic switching of capsular antigens, melanin (antioxidant, inhibits antibody-mediated phagocytosis)

Question 19

What are the four clinical manifestations of aspergillus?

Answer 19

aspergilloma - fungal ball in preformed cavities in the lung (TB, emphysema, COPD)
allergic bronchopulmonary aspergillosis - asthma or CF
disseminated aspergillosis
cutaneous aspergillosis

Question 20

which species of fungus produces aflatoxin? What disease is consumption of aflatoxin associated with?

Answer 20

aspergillus flavus

liver damage and hepatocellular carcinoma

Question 21

what is the treatment for aspergillus?

Answer 21

voriconazole, amphotericin B

Question 22

which fungus is associated with a fruiting head on lactophenol blue stain?

Answer 22

aspergillus

Question 23

what fungus is associated with wide, nonseptate, right-angle hyphae? with thin, septate, acute-angle hyphae?

Answer 23

right angle - zygomycetes

acute angle - aspergillus

Question 24

What are the two clinical manifestations of pneumocystis jiroveci?

Answer 24

pneumonia - “ground glass” appearance on CXR

pneumothorax

Question 25

what is the drug of choice for treatment of pneumocystis?

Answer 25

TMP-SMX (bactrim) | used for prophylaxis too

Question 26

What are the clinical manifestations of zygomycetes?

Answer 26

black, necrotic cutaneous lesions

Question 27

What are the risk factors for zygomycetes?

Answer 27

diabetic ketoacidosis, desferoxamine therapy, neutropenia, bone marrow transplant [diabetic dog named Zygo nawing a bone]

Question 28

How do you treat a zygomycetes infection?

Answer 28

aggressive surgical debridement amphotericin B posaconazole has activity

Question 29

what is the only fungus with a capsule?

Answer 29

cryptococcus | NOT histoplasma capsulatum

Question 30

what fungi is found in pigeon droppings? bat and bird droppings?

Answer 30

cryptococcus | histoplasma

Question 31

Which dimorphic fungi has a mold and spherule form, instead of a normal mold and yeast form?

Answer 31

coccidioides

Question 32

Which fungi is characterized by the mariner's wheel upon visualization by microscopy?

Answer 32

paracoccidioides

Question 33

Which fungi is very common in AIDS patients in northern Thailand?

Answer 33

penicillium marneffei

Question 34

What organ do the systemic endemic dimorphic fungi usually manifest in?

Answer 34

The lungs. Usually cause some sort of pulmonary disease

Question 35

Which fungi has broad based budding?

Answer 35

blastomycetes dermatiditis

Question 36

What diseases does trichophyton cause?

Answer 36

athlete's foot, jock itch, onychomycosis, ringworm

Question 37

what diseases does malassezia fur fur cause?

Answer 37

pytiriasis versicolor - hyper- or hypopigmented patches on the skin usually acquired on the beach

Question 38

What are the clinical manifestations of sporothrix schenckii? How is it commonly acquired?

Answer 38

Subcutaneous nodules that spread along the lymphatic tracts of the arm. Often acquired from the prick of a rose thorn.

Question 39

What are the clinical manifestations of a Madurella infection? How would you treat this kind of infection?

Answer 39

slow progressing ulcerative lesions on the foot (found in soil) with black fungal granules in discharge. Treat with surgical debridement or amputation - doesn't respond well to anti fungal therapy

Question 40

What are the organisms that can cause a fungal pneumonia?

Answer 40

aspergillus, cryptococcus, blastomycetes, histoplasma, coccidioides, paracoccidioides, pneumocystis jiroveci