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Flashcards in Week 228 - Fungal Disease Deck (64):
1

Week 228 - Fungal Disease: What is pneumocystis jirovecii?

Opportunistic fungal parasite which can cause pneumonia in patients with impaired immune systems, such as those with AIDS or are receiving immunosuppressive drugs.

2

Week 228 - Fungal Disease: What is often the cause of candida of the oesophagus?

• Often follows a treatment of broad spectrum antibiotics, steroids or other immunosuppression.

3

Week 228 - Fungal Disease: What is the macroscopic appearance of oesophageal candida?

Soft white plaques.

4

Week 228 - Fungal Disease: How is oesophageal candida diagnosed? How is it confirmed?

• Endoscopic appearance.
• Confirmed by biopsy or brushings.

5

Week 228 - Fungal Disease: How might non-invasive aspergillus affect the following individuals, 1) Heavy exposure but normal, 2) Asthma or cystic fibrosis, 3) Pre-existing cavitating lung disease.

1) Hypersensitivity pneumonitis
2) Allergic bronchopulmonary Aspergillosis (ABPA)
3) Colonisation of cavities - mycetoma

6

Week 228 - Fungal Disease: How would invasive aspergillus affect the immunocompromised?

Invasion of blood vessels and tissues within and outside the lungs.

7

Week 228 - Fungal Disease: What is the pathological mechanism behind hypersensitivity pneumonitis?

• Combination of a type 3 and type 4 immune hypersensitivity response to a large dose of a number of antigens.

8

Week 228 - Fungal Disease: What is a type 3 hypersensitivity reaction?

• Antigen and antibody complexes precipitate in tissues which trigger the complement system leading to inflammatory damage.

9

Week 228 - Fungal Disease: What is a type 4 hypersensitivity reaction?

• T Lymphocytes drive macrophages to cause tissue damage.
• Cell mediated.

10

Week 228 - Fungal Disease: Give some examples of those at risk to hypersensitivity pneumonitis.

• Pigeon fanciers - Serum, feather, faecal proteins.
• Farmers - Fungi in mouldy hay
• Humidifier fever - Organisms in air conditioning
• Brewers - Aspergillus
• Cheese workers - Aspergillus, Penicillium

11

Week 228 - Fungal Disease: What are the symptoms of hypersensitivity pneumonitis?

• Dyspnoea
• Cough
• Fever
• Flu like symptoms
(Develop 4-6hours after exposure)

12

Week 228 - Fungal Disease: What would you find on examination and investigation in someone with hypersensitivity pneumonitis?

• Examination - Fine crackles at the end of expiration.
• Chest X-ray - Diffuse reticulo-nodular shadowing.
• CT thorax - Bilateral areas of consolidation and air trapping.

13

Week 228 - Fungal Disease: What is the treatment for hypersensitivity pneumonitis?

• Prevent further exposure.
• Immunosupression - Reduce bodies excessive T-cell response to antigen.

14

Week 228 - Fungal Disease: What is ABPA?

• Allergic bronchopulmonary aspergillosis.
• In patients with asthma or cystic fibrosis, that have been exposed to a low dose of airborne aspergillosis.

15

Week 228 - Fungal Disease: What are the symptoms of allergic bronchopulmonary Aspergillosis (ABPA)?

• Cough, Dyspnoea, (Worsening of asthma), coughing up casts.

16

Week 228 - Fungal Disease: What is a type 1 hypersensitivity reaction?

• IgE mediated.

• An antigen is presented to CD4+ (Th2) cells, these stimulate B-cells to produce IgE antibodies. These coat mast cells and basophils.
• A secondary exposure to the antigen, causes these sensitised cells to release inflammatory mediators such as histamine and prostaglandins.

17

Week 228 - Fungal Disease: Asthma is due to which type of hypersensitivity reaction?

• Type I

18

Week 228 - Fungal Disease: What is the type 3 hypersensitivity reaction to aspergillus?

• Immune complexes form as antibodies bind to proteins from the fungus.
• These activate the complement system leading to inflammation and damage to local tissues.

19

Week 228 - Fungal Disease: What is the type 4 hypersensitivity reaction to aspergillus?

• Activation of lymphocytes which recruit and activate macrophages.
• The macrophages form granulomas - which cause cell damage.
• This eventually leads to bronchiectasis and fibrosis.

20

Week 228 - Fungal Disease: What is a granuloma?

Ball of highly active macrophages that cause damage to surrounding tissues.

21

Week 228 - Fungal Disease: How is ABPA diagnosed?

• Hyphae in sputum
• Blood -eosinophilia, raised IgE, positive antibodies.
• Positive skin test to aspergillus proteins.
• Broncho-alveolar lavage
• Bronchiectasis develops with time - tram line, ring and gloved finger signs.

22

Week 228 - Fungal Disease: What is the treatment for ABPA?

• Oral steroid to suppress immune mediated damage.
• Management of asthma
• Physiotherapy
• Bronchoscopy to remover plugs if CXR shows collapse lasting more than 7 days.

23

Week 228 - Fungal Disease: What are some of the cavities that can be colonised by aspergillus?

• Old TB
• Abscess
• Bronchiectasis
• Chronic interstitial lung disease

24

Week 228 - Fungal Disease: Why does haemoptysis occur in cavitating aspergillus?

Oxalic acid released from the hyphae causes erosion of the blood vessels.

25

Week 228 - Fungal Disease: What are symptoms of a mycetoma?

(Mycetoma is a fungal ball, that colonises a pre-existing cavity in the lungs)
• May be an asymptomatic incidental finding.
• Recurrent haemoptysis.
• Non-specific weight loss, lethargy.

26

Week 228 - Fungal Disease: What is the histology of a mycetoma?

• Pink necrotic centre.
• Rim of active hyphae.
• Presence of fruiting bodies.

27

Week 228 - Fungal Disease: How is mycetoma diagnosed?

• Radiological appearance.
• Hyphae on sputum cytology.
• Culture of sputum.
• Skin sensitivity test.
• Serum antibodies (precipitins)
• Fine needle / core biopsy.

28

Week 228 - Fungal Disease: What is the treatment of mycetoma?

• Depends on severity of symptoms.
• Can be monitored.
• Anti-fungals no good.
• Surgical resection if troublesome.
• Bronchial artery embolisation.

29

Week 228 - Fungal Disease: What are the symptoms of invasive aspergillosis?

• Gravely ill.
• Rapidly spreading consolidation, necrosis and cavitation of lungs.
• Copious blood stained sputum.

30

Week 228 - Fungal Disease: What is histology of invasive aspergillosis?

• Acute necrotising inflammation with plugging of vessels by fibrin.
• Heavy infiltration by fungus.
• Plugged vessels cause infarction of organs.

31

Week 228 - Fungal Disease: What is the treatment for invasive aspergillosis?

• IV anti-fungals by slow infusion.
- Amphotericin and flucytosine.

32

Week 228 - Fungal Disease: How can mouldy peanuts cause cancer?

• High incidence in Asia of hepatocellular carcinoma caused by Aspergillus growth on mouldy peanuts.
- The aspergillus causes aflatoxin which causes the cancer.

33

Week 228 - Fungal Disease: Give three dermatophytes that are commonly responsible for causing 'ring worm'.

• Trichophyton
• Epidermophyton
• Microsporum

34

Week 228 - Fungal Disease: What are the types of anti fungal therapy?

• Azoles
• Echinocandins
• Allyamines
• Terbinafine
• Polyenes
• Other antifungals

35

Week 228 - Fungal Disease: What is dermatophytosis?

• A superficial localised infection of keratinized tissue such as skin, hair and nails.
• Digest keratin by their keratinases.

36

Week 228 - Fungal Disease: Give examples of dermatophytes and the area they may affect?

• Microsporum - Hair + Skin
• Epidermophyton - Skin and Nails
• Trichophyton - Hair, Skin and Nails

37

Week 228 - Fungal Disease: How does dermatophytosis manifest when in the skin?

Circular, dry, erythematous, scaly, itchy lesions.

38

Week 228 - Fungal Disease: How does dermatophytosis manifest when in the nail?

Thickened, deformed, friable, discoloured nails, subungual debris accumulation.

39

Week 228 - Fungal Disease: How does dermatophytosis manifest when in the hair?

Typical scaly lesions, hair loss.

40

Week 228 - Fungal Disease: What is pityriasis versicolor?

• Superficial infection of stratum corneum (outer layers of the skin).
• Caused by the skin commensal Malassezia furfur

41

Week 228 - Fungal Disease: What infection does Malassezia furfur commonly cause?

• Pityriasis versicolor

42

Week 228 - Fungal Disease: How does pityriasis present?

Hyperpigmented or depigmented macules on the trunk or proximal parts of the limbs.

43

Week 228 - Fungal Disease: What do skin scrapings of pityriasis versicolor reveal?

Yeast cells in clusters and short hyphae (KOH,PAS)

44

Week 228 - Fungal Disease: What is the treatment for pityriasis versicolor?

• Topical - Ketonazole shampoo or other topical agent.
• Oral - Itraconazole or fluconazole

45

Week 228 - Fungal Disease: Which species of candida is most commonly the cause of candidiasis?

Candida albicans

46

Week 228 - Fungal Disease: What is cryptococcosis?

• Fungal infection caused by cryptococcus neoformans.
• Usually presents as CNS infection but can sometimes present as a pulmonary infection, particularly in AIDS patients.
• Pigeon droppings.

47

Week 228 - Fungal Disease: Give examples of endemic or true pathogens (Fungi)?

• Histoplasmosis
• Coccidioidomycosis
• Blastomycosis
• Paracoccidiodomycosis

48

Week 228 - Fungal Disease: Which anti-fungal groups work by inhibiting membrane synthesis?

• Azoles
• Echinocandins
• Allylamines

49

Week 228 - Fungal Disease: Which anti-fungal group work by inhibiting membrane function?

• Polyenes

50

Week 228 - Fungal Disease: How do Flucytosine and Griseofulvin work as anti-fungals?

• Inhibit nucleic acid synthesis and mitosis.

51

Week 228 - Fungal Disease: Azoles are split into two subgroups, what are they give examples of each.

• Imidazoles - Ketoconazole, Topical imidazoles

• Triazoles - Fluconazole, Voriconazole, Itraconazole

52

Week 228 - Fungal Disease: Give an example of Echinocandins.

Capsofungin.

53

Week 228 - Fungal Disease: Give an example of an allylamine.

Terbinafine.

54

Week 228 - Fungal Disease: Give examples of some polyenes.

• Amphotericin B
• Nystatin

55

Week 228 - Fungal Disease: Give the mechanism of action of Azole anti-fungals.

• Inhibit fungal cytochrome p450 which depletes ergosterol in the cell membrane.
• This causes the accumulation of toxic intermediates resulting in the inhibition of growth of the membrane.

56

Week 228 - Fungal Disease: What is Clotrimazole used for?

The topical treatment of candida, tinea pedis and tinea cruris. (Skin only)

57

Week 228 - Fungal Disease: What anti-fungal is used for the treatment of SKIN candida, tinea pedis and tinea cruris?

Clotrimazole (Topical)

58

Week 228 - Fungal Disease: What is Fluconazole used for?

Treatment of Candida, Cryptococcus and dermatophytes.

59

Week 228 - Fungal Disease: What are the side effects of fluconazole?

GI disturbances, liver damage.

60

Week 228 - Fungal Disease: What is Voriconazole used for?

• Fungicidal against Aspergillus and Candida.
• Available orally and IV.

61

Week 228 - Fungal Disease: What are the side-effects of voriconazole?

GI disturbances, visual disturbances.

62

Week 228 - Fungal Disease: What is Itraconazole used for?

Candida, Aspergillus, Cryptococcus, Dermatophytes.

63

Week 228 - Fungal Disease: What are the side effects of itraconazole?

Negative inotropic effect, liver damage.

64

Week 228 - Fungal Disease: What is the mechanism of action of Echinocandins?

• Inhibits 1,3 beta-glucan synthase.
• Reduces glucan in cell wall.
• Weakens the cell wall.