Fungal infections

Question 1

What are fungi?

Answer 1

Eukaryotic organisms with chitinous cell wall and ergosterol containing plasma membranes

Question 2

How to categorise fungi?

Answer 2

Yeasts - Sing cell that reproduces by budding (Candida, cryptococcus)

Moulds - Grow by branching and extension (Dermatophytes, apergillus)

Question 3

Commonest cause of fungal infections in humans?

Answer 3

Candida

Question 4

When does oral candida usually present?

Answer 4

If you are immunocompromised or if you have broad spectrum abx

Question 5

How does superficial candida infection present?

Answer 5

Oral thrush, candida oesophagitis, vulkvovaginit or even cutaneous

Question 6

How to treat superficial candida?

Answer 6

Topical:
Nystatin - Oral
Cotrimazole - Vulvovaginitis, localised cutaneous

Oral:
Fluconazole

Question 7

How does microscopy of yeast look like?

Answer 7

Large clusters

Gram +ve

Question 8

Which patients have a high risk of candidaemia?

Answer 8

(Haem) malignancies
Burns patients
Post op
Long lines

Question 9

What investigations would you do for candida?

Answer 9

Imaging
Beta D glucan serology
Echo to look for endocarditis
Fundoscopy for candida endophthalmitis

Question 10

What is the management for candida?

Answer 10

Echinocandin - Anidulafungin

Remove line or prosthetic materials

Question 11

How to treat candida infection in the CNS?

Answer 11

Ambisome or voriconazole

Question 12

How to treat candida infection in the bones and joints?

Answer 12

Ambisome or voriconazole

Question 13

How to treat candida infection in endocarditis?

Answer 13

Ambisome or voriconazole

Question 14

How to treat candida infection in the urinary tract?

Answer 14

Fluconazole

Question 15

How to treat intra abdominal candida infection?

Answer 15

Peritoneal dialysis with echinocandin or fluconazole

Question 16

What is cryptococcus?

Answer 16

Encapsulated yeast

Question 17

What are the different serotypes of cryptococcus?

Answer 17

A and D - C Neoformans (Immunodeficient)

B and C - C Gattii (Immunocompetent)

Question 18

How is cryptococcus transmitted?

Answer 18

Inhalation of aerosolised organisms

Question 19

Which animal is cryptococcus associated with?

Answer 19

Pigeons

Question 20

What is a risk factor for cryptococcus?

Answer 20

HIV

Organ transplant - Patients taking T cell immunosuppresants (Tacrolimus) - May have menegitis due to this

Question 21

What does a C Gatti infection commonly cause?

Answer 21

Space occupying lesions in brain and lungs

Meningitis

Question 22

What ink is used for cryptococcus stain?

Answer 22

India

Question 23

What serum test / CSF would you do for cryptococcus?

Answer 23

Cryptococcal antigen

Question 24

How to treat cryptococcal meningitis?

Answer 24

Amphotericin B + Flucystosine - 2 weeks

High does fluconazole - 8 weeks

Low does fluconazole - 1 year

Due to high opening CSF pressure, need to repeat lumbar punctures to relieve the pressure

Question 25

On a side note, what can you find on a CSF sample in sub arachanoid haemorrhage?

Answer 25

Xanthochromia - break down of blood products

Question 26

Why do you ask patients to lie down after lumbar puncture?

Answer 26

You may have low CSF pressure so you can get a headache

Question 27

How to test for Aspergillosis

Answer 27

Aspergillus antibodies - Galactomannan

Question 28

How to treat aspergillus

Answer 28

Voriconazole Ambisome

Question 29

What is pneumocystis jiroveci?

Answer 29

Lacks ergosterol in cell wall

Question 30

Who is at risk of getting pneumocystis jiroveci?

Answer 30

Debilitated infants | Severe protein malnutrition

Question 31

How to diagnose pneumocystis jiroveci?

Answer 31

Microscopy PCR Serum Beta D Glucan

Question 32

How to treat pneumocystis jiroveci?

Answer 32

High dose cotrimoxazole | Steroids if hypoxia is present

Question 33

Who is at risk of getting mucormycoses?

Answer 33

Immunosuppresed and diabetic patients

Question 34

How does mucormycoses present?

Answer 34

Rhinocerebral - Cellulitis of orbit and face, black pus form palate and nose, opthalmoplegia, low GCS Pulmonary Cutaneous

Question 35

How to treat mucormycoses?

Answer 35

Broad spectrum anti fungals Surgery

Question 36

How do dermatophytes invade?

Answer 36

Invades dead keratin of skin, hair and nails

Question 37

Name some sites where dermatophytes grow and what the condition is called?

Answer 37

Tinea pedis - Feets Tinea capitis - Scalp Tinea cruris - groin Tinea corporis - abdo

Question 38

What is onichomycosis commonly caused by?

Answer 38

Trichophyton spp

Question 39

What is pitrriasis versicolor caused by?

Answer 39

Malassezia furfur

Question 40

How to treat pityriasis and onichomycosis?

Answer 40

Topical - clotrimazole, ketoconazole

Question 41

What side effects do azoles cause?

Answer 41

Abnormal LFTs

Question 42

What side effects do polyenes cause?

Answer 42

Nephrotoxicity - Potassium, sodium and magnesium wasting

Question 43

What side effects do echinocandins cause?

Answer 43

Relatively innocuous

Question 44

What side effects do pyrimidine analogues cause?

Answer 44

Blood disorders

Question 45

Which part od the fungal cell do polyenes and azoles attacks?

Answer 45

Cell membrane

Question 46

Are azoles P450 inducers or inhibitors?

Answer 46

Inducers

Question 47

Which part of the fungal cell do echinocandins attack?

Answer 47

cell wall - inhibits Beta 1-3 d glucan synthase enzyme

Question 48

Which fungi does echinocandins cover?

Answer 48

Candida Aspergillus Does NOT cover cryptococcus

Question 49

Which part of the fungal cell does pyrmidine analogues such as Flucytosine attack?

Answer 49

DNA RNA synthase

Question 50

What is Flucytosine used for?

Answer 50

Candida and cryptococcal meningitis in combination with ambisome/fluconazole

Question 51

When do you need to monitor Flucytosine blood levels?

Answer 51

When used in conjunction with amphotericin