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Flashcards in Fungal Infections Deck (58)
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1
Q

name the main fungal pathogens

A

aspergillus sp - aspergillus fumigatus
candida sp - candida albicans
cryptococcus sp - cryptococcus neoformans

2
Q

fungal pathogens are what in nature?

A

opportunistic

3
Q

fungal pathogens affect what groups of people?

A

impaired immune system: primary immunodeficiences, HIV/AIDS, malignancies, transplants, premature neonates

chronic lung disease: asthma, CF, chronic obstructive lung disorders

Patients in ICU

4
Q

name common infections caused by: pneumocystis spp

A

pneumocystis pneumonia

ophthalmic pneumocystosis
hepatosplenic infiltrates
renal pneumocystosis
bone marrow infiltrates

5
Q

name common infections caused by: aspergillus spp

A

allergic and invasive pulmonary aspergillosis
aspergilloma

cerebral aspergillosis
keratitis
sinusitis
osteomyeliti
cutaeneous aspergillosis
6
Q

name common infections caused by: candida spp

A

thrush
candidaemia

cerebral abscess
oesophagitis
endocardinitis
hepatic abscess
renal abscess
urinary candidiasis
vulvovaginal candidiasis
osteomyelitis
cutaneous candidiasis
onchomycosis
7
Q

name common infections caused by: cryptococcus spp

A

meningitis

cerebral absecc
endophathlamitis
pulmonary infiltrates
endocarditis
crytococcaemia
renal abscess
subcutaneous abscess
8
Q

what is mucocutaneous candidiasis associated with?

A

antibiotic use

9
Q

where is mucocutaneous candidiasis found?

A

moist areas

10
Q

oral candidiasis is associated with?

A

inhalation steroids

11
Q

what age group are vulnerable to mucocutaneous candidiasis?

A

< 3 months

12
Q

presenting symptoms of primary immunodeficiency disorders

A

neutropenia
low CD4+ T cells
impaired IL-17 immunity

13
Q

what are the 4 types of impaired IL-17 immunity?

A

AD-hyper IgE syndrome - deficit of IL-17 producing cells

Dectin-1 deficiency - reduced IL=17 producing cells

CARD9 deficiency - low proportion of circulating IL-17 T cells

APECED syndrome - high titers of neutralising Ab against IL-17A, IL-17F and/or IL-22

14
Q

most invasive candidiasis infections are what in origin and why?

A

endogenous because gut commensal

15
Q

what can invasive candidiasis present as?

A

bacterial blood stream infection

16
Q

what is the mortality rate of invasive candidiasis?

A

up to 40%

17
Q

risk factors for developing invasive candidiasis

A

broad spectrum antibiotics
intravascular catheters
TPN
abdominal surgery

18
Q

how can you diagnose invasive candidiasis?

A

Take a blood culture or culture from a normally sterile site. B-d-glucan high NPV and performs very well to exclude invasive candidiasis. Recent developments in PCR assays very promising. In infants and children performance lower due to sampling issues.

19
Q

how is aspergillus spread?

A

airborne

20
Q

describe aspergillus spores

A

hydrophobic conidia

diameter approx 2-3um

21
Q

name the classification of pulmonary aspergillus disease

A

acute invasive pulmonary aspergillosis
chronic pulmonary aspergillosis
allergic aspergillosis

22
Q

who gets acute invasive pulmonary aspergillosis?

A

neutropenic patients
post transplant: stem cell > solid organ
patients with defects in phagocytes

23
Q

who gets chronic pulmonary aspergillosis?

A

patients with underlying chronic lung conditions

24
Q

when does aspergillosis pulmonary become chronic?

A

3 months

25
Q

who gets allergic aspergillosis ?

A

allergic bronchopulmonary aspergillosis in CF ans asthma

asthma or CF with fungal sensitisation

26
Q

describe effects acute invasive pulmonary aspergillosis

A

rapid and extensive hyphal growth
thrombosis and haemorrhage
angioinvasive and dissemination

27
Q

acute invasive pulmonary aspergillosis signs and symptoms

A

absent or non specigic

persistent febrile neutropenia despite broad spectrum antibiotics

28
Q

acute invasive pulmonary aspergillosis mortality

A

50%

29
Q

effects of sub acute invasive pulmonary aspergillosis

A
non-angioinvasive
limited fungal growth
pyogranulomatous infiltrates
tissue necrosis
excessive inflammation
30
Q

who does sub acute invasive pulmonary aspergillosis affect?

A

non-neutropenic host (graft vs host disease, neutrophil disorders)

31
Q

signs and symptoms of sub acute invasive pulmonary aspergillosis

A

non-specific

mild-moderate systemic illness

32
Q

sub acute invasive pulmonary aspergillosis mortality

A

20-50%

33
Q

discuss invasive aspergillosis as a presenting symptom of primary immunodeficiency

A
• Congenital neutropenia
• Chronic granulomatous disease
o Phagocytic disorder
• Hyper IgE syndrome (Job’s syndrome)
o Phagocytic disorder and impaired IL-17 pathway
• CARD-9 deficiency
o Innate immune pathways, killing defect

Clinical presentation is often outside the lungs; e.g. bones, spine, brain, abdomen.

34
Q

discuss chronic pulmonary aspergillosis

A

• Asthma, cystic fibrosis, chronic obstructive lung disorders
• Pulmonary exacerbations (not responding to antibiotics)
• Lung function decline
• Increased respiratory symptoms as cough, decreased exercise tolerance and dyspnoea
• Positive sputum cultures for aspergillus
o 50% of CF patients are infected
• High morbidity but causative mortality rates less clear

35
Q

discuss allergic bronchopulmonary aspergillosis

A

Immunological responses to a variety of A. fumigatus antigens in the CF-host (10-15%) result in:
• Acute/subacute deterioration of lung function and respiratory symptoms
• New abnormalities chest imaging
• Elevated IgE level
• Increases aspergillus specific IgE or positive skin test
• Positive aspergillus specific IgG

36
Q

pulmonary aspergilloma who does it affect?

A
tuberculosis
sarcoidosis
bronchiectasis
bronchial cysts and bullae
after pulmonary infections
37
Q

emerging non-neutropenic hosts vulnerable to aspergillus?

A
  • Respiratory insufficiency > intubation ICU
  • Influenza A > Th: oseltamivir, corticosteroids, antibiotics
  • A. fumigatus in sputum by day 3
38
Q

diagnosis of pulmonary aspergillosis in the non-neutropenic host

A

cultures of sputum and/or bronchoalveolar lavage, and/or biopsy
aspergillus specific IgG or IgE in chronic and allergic

39
Q

diagnosis of pulmonary aspergillosis in the neutropenic host

A

high resolution CT chest - halo sign, air crescent sign
molecular markers in blood: galactomannan and PCR aspergillus
BAL and biopsies if clinical condition allows

40
Q

how cryptococcus is spread?

A

inhalational

41
Q

where can cryptococcus be found?

A

bark on a variety of trees
bird faeces
organic matter

42
Q

what can cryptococcus cause?

A

pulmonary infection ranging from asymptomatic to pneumonia

43
Q

cryptococcus can disseminate to the brain causing?

A

meningoencephalitis in HIV and AIDS patients

44
Q

clinical presentation of cryptococcus

A
headache
confusion
altered behaviour
visual disturbances 
coma due to raised ICP in 60-80%
45
Q

diagnosis of cryptococcal disease: CSF

A

Indian Ink preparation
culture
high protein and low glucose
cryptococcus antigen

46
Q

diagnosis of cryptococcal disease: blood

A

culture

cryptococcus antigen

47
Q

mortality of cryptococcal meningitis

A

africa - 3 month mortality 70%

US - 3 month mortality 25%

48
Q

what factors are associated with mortality in cryptococcal meningitis?

A
delay in presentation and diagnosis
lack of access to antifungals
inadequate induction therapy
delays in starting antiretroviral therapy
immune reconstitution syndrome
49
Q

what antifungals can be used to treat invasive fungal infections? inc route

A

amphotericin B formulation (IV)
azoles (IV, oral)
ehinocandins (IV)
flucytosine (IV, oral)

50
Q

how does amphotericin B work>

A

acting on ergosterol causing lysis

51
Q

how do azoles work?

A

inhibit ergosterol synthesis

52
Q

how do echinocandins work?

A

inhibit glucan synthesis

53
Q

how does flucytosine work?

A

inhibit fungal DNA synthesis

54
Q

what antifungal has the broadest activity?

A

AmB

55
Q

what can be used to treat invasisive candidiasis?

A

echinocandins and fluconazole

56
Q

what can be used to treat (acute) invasive aspergillosis?

A

voriconazole and isavuconazole

57
Q

what can be used for antifungal prophylaxis?

A

itraconazole and posaconazole

58
Q

what can be used for the maintenance of cryptococcal meningitis?

A

AmB + flucytosine followed by fluconazole

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