Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Year 2 > Fungal Infections > Flashcards

Fungal Infections Flashcards

1
Q

What type of cells are fungi

A

Eukaryotic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is their cell wall made of

A

Chitin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Fungi are heterotrophic, what does this mean?

A

An organism that can’t manufacture its own food and instead obtains its food and energy by taking in plant and animal matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does fungi ‘grow’

A

Produce spores which move through water and air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is fungus so infectious

A

High reproductive rate

Slow death so can spread before numbers thin

Broad host range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Yeast vs Mould

A
  1. Yeast - single celled
    Mould - multicellular
  2. Yeast divide by budding whilst moulds develop from hyphae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are dimorphic fungi

A

They can switch from being yeast to mould depending on the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is hyphae

A

Branching from the cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Example of a dimorphic fungus

A

Coccidiodes immitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Ideal conditions for C immitis

A

Warm, arid conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When does C immitis grow as mould

A

ambient temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is C immitis spread

A

Light so by wind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When do C immitis convert from mould to yeast

A

At body temperature after inhalation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What disease does C immitis cause

A

Pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why do not many fungi cause human infection

A
  1. Denature at 37 degrees

2. Our strong immune responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How common are life-threatening fungal infections

A

Very uncommon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is Otitis Externa

A

Inflammation of external ear canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is Onychomycosis

A

Final nail infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is Tinea Pedis

A

Athlete’s foot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Name five fungi which can cause life-threatening disease in immunocompromised hosts

A
  1. Candida
  2. Invasive aspergillosis
  3. Pneumocystis
  4. Cryptococcosis
  5. Mucormycosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does candida commonly cause in the mouth

A

Thrush

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why does Invasive aspergillosis take place

A

Cause the immune system can’t stope spores from reaching the bloodstream via the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does invasive aspergillosis often cause

A

TB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Two life-threatening fungal diseases in healthy hosts

A
  1. Fungal asthma

2. Travel associated fungal infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Four characteristics of selective toxicity drugs for fungal infections

A
  1. Target receptors not in humans
  2. Target receptors is different to any human analogues
  3. Drug is concentrated in organism cell
  4. Increased permeability to compound
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How do human cells survive selective toxicity drugs

A
  1. They use alternative metabolic pathways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why is selective toxicity more difficult for fungi than bacteria

A

Eukaryotic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Four components of the final cell wall

A
  1. Mannoproteins
  2. B1,3, gluons
  3. B1,6 gluons
  4. Chitin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the plasma membrane of fungus made of

A

Ergosterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Difference in composition of plasma membrane in humans and fungus

A

1, Humans have cholesterol in wall whilst fungi have ergosterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is an amphoteric molecule

A

A molecule with both acid and alkaline properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What do amphoteric drugs act on in fungal cells

A

Drugs bind to ergosterol in membrane forming pores in membrane, k+ leakage and death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Why are polyenes like amphoteric drugs selective

A
  1. 10 times lower affinity for cholesterol in mammalian membrane s
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Does this mean polyenes can’t cause damage in host cells

A

No, they can (dose dependant)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are side-effects of polyenes

A
  1. Anaphylactic reactions, hypotension
  2. Hyperkalemia
  3. Hypokalaemia if distal renal uses are effected
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Describe the ergosterol synthetic pathway

A

Acetyl CoA -> Farnesyl Pyrophosphate -> Squalene -> Squalene Eposide
-> Lanosterol -> 4,4-dimethylcholesta-8,14,24-trienol -> 4,4-dimethyltrymosterol -> Fecosterol -> Episterol -> Ergosta-5,7,24(28)-trienol -> Ergosterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What type of drug is Terbinafine

A

Allylamines

38
Q

How does Terbinafine work

A

Reversible inhibition of squalene epoxidase

39
Q

What is the bioavailability of Terbinafine

A

45%

40
Q

Where is Terbinafine usually metabolised

A

First pass metabolism in the liver

41
Q

Where is Terbinafine distributed to

A

Poorly perfused sites (skin and nails)

42
Q

What is Terbinafine usually used to treat

A

Dermatophytes (Candida, aspergillus)

43
Q

Two side-effects of Allyamines

A

Taste disturbance, deranged LFT, increased CYP450 metabolism

44
Q

What do azoles inhibit

A

Lanosterol

45
Q

Role of triazoles

A

Inhibit secondary targets in synthetic pathways

46
Q

Name an azalole used to inhibit lanosterol

A

Fluconazole

47
Q

What are clotrimazole and Ketoconazole active against

A

Candida

48
Q

Adverse effects of azoles

A
  1. Transaminitis

2. GI SEs

49
Q

Adverse effects unique to itraconazole

A

Nausea, diarrhoea

Liver failure

50
Q

Adverse effects unique to Voriconazole

A

30% suffer from reversible visual disturbances

51
Q

Why do azole drug-drug interactions occur

A
  1. Result of CYPP450
52
Q

Why are azole drug-drug interactions so rare for Fluconazole

A
  1. Hydrophilic and easily excreted
53
Q

What does Fluconazole inhibit

A

Warfarin, phenytoin, anxiolytics

54
Q

Which is a stronger inhibitor, intra or post

A

Itra

55
Q

What does Itraconazole and Posaconazole inhibit

A

CYP3A4

56
Q

What does Voriconazole inhibit

A

CYP enzymes (some of the smaller ones)

57
Q

Why are Candida displaying azole resistance

A
  1. Mutations in ERG11 gene
  2. Increased expression for ERG11
  3. Causes efflux
58
Q

What drugs are most effected by azole resistance in Candida

A

Fluconazole and Voricaonzole

59
Q

What do Echinocandins inhibit

A

1,3 beta-glucan synthase

60
Q

Define fungistatic

A

Inhibit growth of fungus

61
Q

What type of cells are Echinocandins fungistatic towards

A

moulds at hyphen tip

62
Q

What the of cells are Echinocandins fungicidal towards

A

Yeast

63
Q

What cell are resistant to Echinocandins

A
  1. Species with large amounts of 1,3 gluten in cell wall
64
Q

What species are resistant to Echinocandins

A
  1. Zygomycetes
  2. Cryptococcus
  3. Trichosporon
  4. Fusarium
65
Q

What is inconvenient about Echinocandins

A
  1. Poor oral bioavailability (IV only)

2. Poor penetration in some parts of the body (CSF, eye)

66
Q

What is a convenience of Echinocandins

A

Limited, and rare drug toxicity

  1. Concentration dependant killing
  2. Prolongues antibiotic effect
67
Q

What fungal infection does this patient have

  1. 60 yr old man has acute gallstone pancreatitis with pseudocysts
  2. Stable on transfer
    1 week later:
  3. Febrile >38 despite antibiotics
  4. Haemodynamics relatively stable
  5. Fungal infection found in line tip and blood
A

Invasive Candida infection

68
Q

How can we maximise sensitivity for fungi during diagnosis

A
  1. Pick up from tissue and fluids if can be obtained (best place to pick up)
69
Q

Blood culture efficiency for fungi vs bacteria

A

Blood culture only half as sensitive n fungi

70
Q

Why can we detect if there is a fungal infection within the body by using blood

A
  1. 1,3 gluten released by cell membrane into plasma
71
Q

Inconveniences of blood samples for fungi

A
  1. Prone to contamination

2. Non-specific for individual fungi

72
Q

Most common Candida in hospital patients

A
  1. Candida albicans
73
Q

What two drugs are candida most susceptible to

A
  1. Echinocandins

2. Polyenes (ampotericin B)

74
Q

What fungal infection is this man suffering from:

  1. 43 year old
  2. Found unconscious
  3. Lesion on CT in brain
  4. Serum galactomanna found
A

Aspegillus

75
Q

How do we know the 43 year old man is suffering from Aspergillus infection

A

Because Galactomannan is found in Aspergillus cell walls as an antigen

76
Q

Two drugs that inhibit ergosterol synthesis

A

Azole

Allyamines

77
Q

Drug that inhibits formation of cell wall gluten

A

Echinocandin

78
Q

Drug that inhibits DNA and RNA synthesis

A

Pyrimidine (5-fluuorocytosine)

79
Q

Drug that inhibits microtubule assembly

A

Grisan

80
Q

How common is Onychomycosis

A

Very

81
Q

What is Onchomycosis caused by

A

Dermatophyte moulds

82
Q

When do dermatophyte moulds grow best

A

30 degrees

83
Q

What species causes Onchymycosis

A

Trichopyton Rubrum

84
Q

What is the most specific test for Onchymycosis

A

Microscopy (30% culture negative)

85
Q

Two treatment options for Onchymycosis

A
  1. Topical Amorolfine

2. Itraconazole and Terbinafine

86
Q

What is Amorolfine

A

Morpholine

87
Q

How does Amorolfine work

A

Stops production of ergosterol

88
Q

What fungus has caused the following:

  1. 75 yrs old
  2. Admitted with onset respiratory failure
  3. Pulmonary oedema was primary diagnosis
  4. Beta gluten positive
A

Could be any cause every fungus has 1,3 gluten.

HOWEVER, since it effects the lungs it is pneumocystis

89
Q

When is pneumocystis most common

A

Early in life

90
Q

What patients usually get pneumocystis later in life

A

Immunocompromised

91
Q

What clinical indication for pneumocystis is there

A
  1. Hypoxia is more severe than tests are suggesting

Year 2 (155 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions