Fungal infections

Question 1

2 types of fungi

Answer 1

Yeast

Mould

Question 2

Reproduce by budding
Single cells living alone
E.g. Candida, cryptococcus

Answer 2

Yeast

Question 3

Reproduce by forming spores from ends of hyphae
Live as multicellular ‘hyphae’ filaments
E.g. Aspergillosis, dermatophytes

Answer 3

Mould

Question 4

BD glucan assay
Cottage cheese discharge
White plaques
Mucosal surfaces

Answer 4

Candida (albicans)

Question 5

Candida albicans Tx

Answer 5

Fluconazole

Question 6

Sabouraud agar
Bird droppings
Affinity for CNS - meningoencephalitis
AIDS
India Ink staining (halos around yeast cells)

Answer 6

Cryptococcus neoformans

Question 7

Meningitis in apparently imunocompetent individuals

Answer 7

C neoformans gattii variety

Question 8

Tx for Cryptococcus neoformans

Answer 8

Amphotericin +/- flucytosine

Question 9

What used to be used to detect Cryptococcus?

What is used to detect Cryptococcus now?

Answer 9

Used to use India Ink staining (halos around yeast cells)

Now use antigen testing in blood and CSF

Question 10

Stored grains
Can cause aspergilloma, ABPA, invasive aspergillosis
Lungs (pneumonia)
B-glucan test
Czaoek dox agar

Answer 10

Aspergillus (fumigatus, flavus)

Question 11

ABPA

Answer 11

Type 1 hypersensitivity

Question 12

Tx of Aspergillus

Answer 12

High-dose Amphotericin B

Surgical removal of aspergilloma

Question 13

Affect skin, hair, nails (keratin containing)
Humid moist skin folds
Ring worm, athlete’s foot
Dermatophytes - Trichophyton, Microsporum, Epidermophyton

Answer 13

Tinea

Question 14

Two ways of classifying fungal infections

Answer 14

Superficial / Deep

Yeasts / Moulds

Question 15

Superficial fungal infections

Answer 15

Tinea
Pityriasis
Candida (superficial in immunocompetent)

Question 16

Deep fungal infections

Answer 16

Candida (deep in immunocompromised)
Aspergillus
Cryptococcus

Question 17

Raised red rings with central clearance on hairless skin

Surrounding skin dry and flaky

Answer 17

Tinea corporis (ringworm)

Question 18

Crotch ith

Red or brown skin patch with clear rings

Answer 18

Tinea cruris

Question 19

Athletes foot

Answer 19

Tinea pedis

Question 20

Scaly red lesions on head leading to hair loss

Expanding red ring on scalp

Answer 20

Tinea capitis

Question 21

Spherical opacity on CXR

Answer 21

Aspergilloma

Question 22

White / yellow nail
Thick nail
Separation of nail from nailbed

Answer 22

Onychomyosis

Question 23

Malassezia furfur
Hypopigmentation in dark skin / hyperpigmentation in fair skin
Spaghetti with meatballs with KOH
Orange fluorescence Woods light

Answer 23

Pityriasis (tinea) versicolor

Question 24

Affinity for vascular structures
Rhinocerebral - cellulitis, plack pus from nose / palate
Rapid referral to ENT

Answer 24

Mucormycoses

Question 25

3 types of anti-fungals + examples

Answer 25

1. Target cell membrane (ergosterol) - azoles, Amphotericin B 2. Target DNA synthesis - flucytosine 3. Target cell wall (beta-1,3-glucan) - echinocandin

Question 26

Anti-fungals targetting cell membrane

Answer 26

``` Azoles (cell wall synthesis) Amphotericin B (cell wall integrity) ```

Question 27

Anti-fungal that binds CYP450 enzyme lanosterol 14alpha-demethylase (req. to form ergosterol)

Answer 27

Azoles

Question 28

Anti-fungal that binds sterols in fungal cell membrane Transmembrane channel w/ electrolyte leakage Nephrotoxic Used in invasive serious fungal disease

Answer 28

Amphotericin B

Question 29

Anti-fungal that is a pyrimidine analogue Selectively activated by fungi Resistance - now only used in combination with other agents

Answer 29

Flucytosine

Question 30

Anti-fungal that inhibits cell wall B-glucan synthesis

Answer 30

Echinocandin (e.g. caspofungin)

Question 31

Mississippi river region | Chronic progressive lung disease

Answer 31

Histoplasma capsulatum

Question 32

Copper coloured soil saprophyte on rotting wood | Warty cauliflower lesion

Answer 32

Phialophora verrucose

Question 33

Rose thorn exposure | Nodules on skin

Answer 33

Sporothric schenkii | 'Rose Gardeners' disease