Fungal Infections

Question 1

what are moulds

Answer 1

multicellular, filamentous fungi which produce hyphae

Question 2

what are yeasts

Answer 2

unicellular, round or oval cells, reproduce by budding or fission

Question 3

what are the common symptoms of tinea infections

Answer 3

itching, burning, pain, irritation

Question 4

what are risk factors for tinea infections

Answer 4

environmental, clothing, hyperhidrosis, immunicompromised

Question 5

what causes tinea infections

Answer 5

dermatophytes

moulds and keratinophilic

Question 6

what are the three types of ringworm

Answer 6

tinea corpis = skin
tinea cruris = groin
tinea capitis = scalp

Question 7

what are some treatments for ringworm

Answer 7

corporis and cruris = topical imidazole (clotrimazole, econazole or miconazole) also terbinifine >12s
oral therapy is terbinafine, itraconazole, griseofulvin (rural areas)

Question 8

treatment for tinea capitis

Answer 8

oral treatment in addition to ketoconazole, selenium sulphide shampoos twice weekly

Question 9

what is griseofulvin used to treat

Answer 9

microsporum spp

Question 10

what is terbinafine used to treat

Answer 10

trichophyton

Question 11

what are the features of griseofulvin

Answer 11

short half life
not retained well in keratin so longer therapy needed
narrow therapeutic range
avoid in liver disease/pregnancy/breastfeeding

Question 12

what are the side effects of griseofulvin

Answer 12

GI, headache, cognitive, hepatobiliary, alcohol may potinate effects, interacts with oral contraceptives, take with or after fatty food to improve absorption

Question 13

what is tinea pedis

Answer 13

athletes foot

Question 14

what is chronic hyperkeratotic tinea

Answer 14

patchy fine dry scaling on the bottom of the feet

Question 15

what are the symptoms of athletes foot

Answer 15

moist peeling, irritable skin between toes, clusters of blisters or pustules on the side of the feet or insteps, ringworm like tinea corpis

Question 16

what people are prone to athletes foot

Answer 16

more exposed to the spores at home or during activities, their skin may produce less fatty acid, they wear occlusive footwear, they wear the same pair of shoes or socks for a long period of time, they sweat excessively, they have poor circulation in feet

Question 17

what species’ can cause athletes foot

Answer 17

trichophyton rubrum
trichophyton mentagrophytes
epidermophyton floccosum

Question 18

what is first line treatment for tinea fungal infection

Answer 18

imidazole cream 2-4wks
terbinafine cream 1wk (>12s)
combine with hydrocortisone if inflammed

Question 19

what to use if topical antifungals are ineffective for tinea infection treatment

Answer 19

terbinafine 250mg od 2-6wks
itraconazole 100mg od for 30 days or 200mg bd 7days
griseofulvin 500-1000mg daily o divided dose 4-8wks

Question 20

what is onychomycosis

Answer 20

fungal infection of the nails

Question 21

what are the common infective species of onychomycosis

Answer 21

trichophyton rubrum
epidermophyton floccosum
trichophyton mentagrophytes
candida

Question 22

what are the most effective therapies for onychomycosis

Answer 22

terbinafine and itraconazole

scrapings of the nail are needed

Question 23

what is the most common subtype of onychomycosis

Answer 23

DLSO
d=distal (top of nail)
l=lateral (side of nail)
s=subungal 
o= oncychomycosis

Question 24

what is the systemic management of onchomycosis

Answer 24

1st line= terbinafine 250mg od

itraconazole 200mg bd for 7 days

Question 25

what is pulse therapy

Answer 25

shorter, high dose | drug still remains in keratinised tissue but lower risk of side effects

Question 26

what is the topical management of onychomycosis

Answer 26

mild disease or people who cannot take oral products | amorolfine (once or twice weekly for 6 months)

Question 27

what does pityriasis versicolor look like

Answer 27

macules and/or patches of variable appearance (hyperpigmented), surrounded by normal skin lesions worsen in tropical climates affected areas include back, chest, abdomen, neck, upper limbs face commonly affected in children

Question 28

what is pityriasis versicolor

Answer 28

colonisation of stratum corneum, starts around puberty as the fungus feeds off fatty acids in sebum - it lives on the skin

Question 29

how is pityriasis versicolor diagnosed

Answer 29

using a Wood's lamp | yellow to yellow-green flouresence

Question 30

what is the treatment for pityriasis versicolor

Answer 30

topical shampoos that will cover large areas imidazole cream if small area systemic itraconazole if topical insufficient

Question 31

what causes superficial candida infections

Answer 31

candida albicans c. glabrata c. krusei

Question 32

what topical therapies are used for oropharyngeal candida (oral thrush)

Answer 32

``` topical = imidazole like miconazole oral gel, polyene antifungals like nystatin oral= fluconazole ```

Question 33

what is genital candidiasis

Answer 33

vaginal thrush

Question 34

how does genital candidiasis present

Answer 34

intense vaginal and vulval pruritus, thick white discharge, pain on intercourse and urination

Question 35

what treatment is used for genital candidiasis

Answer 35

imidazoles like clotrimazole | oral fluconazole or itraconazole

Question 36

what is cutaneous candidiasis

Answer 36

folds of the skin, especially areas that chafe

Question 37

what are the risk factors for cutaneous candidiasis

Answer 37

systemic antibiotics, HIV, skin conditions, skin maceration

Question 38

what does disseminated mean

Answer 38

spread from initial localised source of infection

Question 39

what is fungaemia

Answer 39

fungus detected in blood

Question 40

what is severe sepsis

Answer 40

sepsis in addition to induced organ dysfunction/tissue hypo-perfusion

Question 41

what is sceptic shock

Answer 41

sepsis induced hypotension persisting despite adequate fluid resuscitation

Question 42

what happens during sepsis

Answer 42

circulatory system cannot handle supply demands of the body, inflammatory mediators compromise integrity of blood vessels, leaky blood vessels (intravascular fluid leaks out and reduces blood pressure) reduction in blood pressure leads to hypoperfusion of organs multi-organ failure and death

Question 43

why are fungi more toxic

Answer 43

there is less specificity between fungal and mammalian cells as they are both eukaryotic

Question 44

what are the types of fungal infection

Answer 44

invasive, disseminated, fungaemia, distant site infection

Question 45

what indirect tests can confirm an invasive fungal infection

Answer 45

galactomannan antigen detected in sample beta D glucan detected in serum MC&S in sputum

Question 46

what are the main causative organisms of invasive fungal infections

Answer 46

candida spp, aspergillus spp, cryptococcus spp, histoplasma capsulatum

Question 47

what is apergillus

Answer 47

a mould that is common in the environment and can cause pulmonary infection (opportunistic) blood cultures are difficult to obtain but antibody detection can be used

Question 48

what is aspergillosis

Answer 48

invasive aspergillosis has lung origin

Question 49

what is aspergilloma

Answer 49

a fungal ball growing in preexisting cavity | saprophytic

Question 50

what are the complications of invasive pulmonary aspergillus

Answer 50

pneumonia, dissemination to CNS, local invasion to heart/vessels surgery to remove locally invasive regions

Question 51

what is the most common species of yeast

Answer 51

cryptococcus neoformans | cause pulmonary and invasive CNS infections

Question 52

what is histoplasma capsulatum

Answer 52

environmental pathogen that causes pulmonary disease

Question 53

what drugs are in the azole category

Answer 53

imidazoles (topical), triazoles (fluconazole, itraconazole, posaconazole, voriconazole)

Question 54

what drugs are in the echinocandins category

Answer 54

caspofungin, anidulafungin

Question 55

what drugs are in the polyenes category

Answer 55

amphoterocin

Question 56

what is the triazoles mechanism of action

Answer 56

decreased ergosterol production throug inhibition of fungal cytochrome p450 enzymes, most are stativ

Question 57

what are the side effects of triazoles

Answer 57

hepatic derangement, QT prolongation

Question 58

what is the mechanism of action of amphoterocin

Answer 58

beinds to ergosterol in fungal cell membrance, creates pores, increasing permeability cidal broad spectrum but poor oral absorption so IV only lipid formulation has reduced renal toxicity

Question 59

what are the side effects of amphoterocin

Answer 59

renal toxicity, electrolyte disturbances, infusion reactions, cardiotoxicity, hepatotoxicity, blood dyscrasias

Question 60

what are echinocandins

Answer 60

inhibit 1,3-beta-glucan synthase, prevent beta-glucan synthesis

Question 61

what are some examples of echinocandins

Answer 61

capsofungin, anidulafungin, micafungin

Question 62

what is flucytosine

Answer 62

nucleoside analogue, synergism with amphoterocin, need to do plasma levels, large problem with resistance