Brainscape's Knowledge GenomeTM

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


See full index

DTMH Block 3 > Deep Mycoses > Flashcards

Deep Mycoses Flashcards

1
Q

Define ‘deep fungal infection’

A

Any infection below the stratum corneum (in the keratin layer)

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

Are deep mycoses confined to tropical regions?

A

No! But more common due to
- medical care
- drug availability
- natural infectious sources
- lack of PPE

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

What is the difference in the inflammatory response to a deep fungal infection in the immunocompetent versus immunocompromised?

A

Immunocompetent
- standard inflammatory response
- granulomatous, neutrophilic microabscesses

Immunocompromised
- anergia response (non-specific, lots of histiocytes)
- florid infection
- often disseminated

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

What is the modality of choice for diagnosis of deep fungal infection?

A

Fungal culture
Best alternative - histology

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

What is a mycetoma?

A

A general term for chronic, subcutaneous granulomatous infection with draining sinuses and fistulae

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

What is the difference in the granule colour in actinomyces versus maduromycoses?

A

Actinomyces - yellow
Maduromycoses - black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is maduromycoses?

A

“Madura foot”
Was originally used for maduromycoses (madurella species) but now is generalised

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

What are the 3 kinds of mycetoma?

A

Eumycotic (true fungi)
Actinomycotic (branching bacteria)
Botryomycotic (clump forming bacteria)

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

What is the pathogenesis of mycetoma?

A
  1. Inoculation of causative agent into soft tissue
  2. Begins as a small nodule which discharges pus, often with granules
  3. Develops slowly via centrifugal extension along the fascial planes
  4. Eventually, bony destruction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the response of mycetoma on microscopy regarding each causative agent?

A

Uniform response irrespective of agent - neutrophilic micro abscesses

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

What are the features of mycetoma on histology?

A

Epidermal acanthuses
Parakeratosis
Orthoketatosis
Multinucleate giant cells
Splendore-Hoeppli phenomenon
Peripheral fibrosis

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

Which feature of mycetoma on histology is mistake for SCC?

A

Orthokeratosis

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

Where do you look for the organisms on histology?

A

In the micro abscesses

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

What is the Splendore-Hoeppli phenomenon?

A

Eosinophilic antigen-antibody response around an organism (not specific to fungi)

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

Why does peripheral fibrosis confound therapy of mycetoma?

A

Causes poor drug penetration

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

Name causative organisms of eumycotic mycetoma

A

Madurella mycetomi
Allescheria boydii
Phialophera species

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

Name causative organisms of botryomycotic mycetoma

A

Nocardia brasiliensis
Streptomyces
Actinomyces

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

Name causative organisms of actinomycotic mycetoma

A

Staph
Strep
E.coli
Proteus
Pseudomonas

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

How is mycetoma distinguished?

A

Gram
Grocott’s
PAS
ZN

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

Which organism is the most common infective organism of the eumycotic mycetoma group?

A

Madurella mycetomi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which actinomyces is most common in the actinomycotic group?

A

Actinomyces israelii

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

Why are pathological changes needed to confirm actinomyces israelii?

A

Commensal of the mouth and female genital tract

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

What are common sites of actinomycosis?

A

Cervicofacial
Thoracic
Abdominal
IUCD

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

What are the features of nocardia asteroids?

A

Delicate
Partially acid fast

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

In which population is nocardiosis more common?

A

HIV patients

26
Q

What condition of nocardiosis often confused with?

A

TB

27
Q

What sites does nocardiosis like to infect?

A

Lung
Sinuses
Brain
Soft tissue
Abdomen

28
Q

How do you differentiate actinomyces from nocardia?

A

Actinomyces
- anaerobic
- not acid fast
- oral and gut
Nocardia
- aerobic
- acid fast
- soil exposure

29
Q

What is chromomycosis?

A

Dermaticeous brown fungi from decaying wood and soil

30
Q

What does chromomycosis look like on histology?

A

“Stack of pennies”
Epidermal hyperplasia

31
Q

Which organisms cause chromomycosis?

A

Phialophera verrucosa
P. pedrosai
P. compost
P. dermatitis
Oladosporiom carionii

32
Q

What is the treatment of chromomycosis

A

5-flurocytosine
Amphotericin B (resistance common)

33
Q

Which organism causes sporotrichosis?

A

Sporothrix schenckii

34
Q

What is the clinical presentation of sporotrichosis?

A

Painless nodule at inoculation site with dissemination along the lymphatics

35
Q

Discuss the histological features of sporotrichosis

A

Small, spherical, cigar-shaped bodies
Asteroid bodies
Splendore-Hoeppli phenomenon
Epidermal hyperplasia
Neutrophilic microabscesses

36
Q

How does sporotrichosis present in HIV patients?

A

Florid infection, easily misdiagnosed
Proliferation of intracytoplasmic cigar shaped spores

37
Q

What is the treatment of sporotrichosis?

A

Potassium iodide

38
Q

How is sporothrix different to cryptosporidium on microscopy?

A

Sporothrix = mucicarmine negative

39
Q

Which histoplasma capsulatum type is worldwide versus only in Africa?

A

Worldwide - var capsulatum
Africa - var duboisii

40
Q

What is the clinical presentation of histoplasma capsulatum?

A

Papulonodular lesions of the skin and subcutaneous tissue

41
Q

Which yeast are the spores of histoplasma capsulatum similar to?

A

Candida granulomatis

42
Q

Which stains are positive for histoplasma capsulatum?

A

PAS
Grocott’s
H&E (may be refractive)

43
Q

Which type of necrosis is seen in histoplasma capsulatum?

A

Caseous necrosis (also cryptosporidium)

44
Q

Which site is common for histoplasma capsulatum and why?

A

Nose - cooler temperature

45
Q

How do you differentiate histoplasma capsulatum from cryptosporidium?

A

Histoplasma = small and uniform

46
Q

What is a differential diagnosis for histoplasmosis?

A

Leishmaniasis

47
Q

How is histoplasmosis transmitted?

A

Inhalation (recreational and occupational)

48
Q

What is the majority of clinical presentations of histoplasmosis?

A

90% subclinical with spontaneous resolution

49
Q

What are symptomatic presentations of histoplasmosis?

A
  1. Acute pulmonary infection
  2. Chronic pulmonary histoplasmosis
  3. Disseminated histoplasmosis
50
Q

Discuss the features of acute pulmonary histoplasmosis

A

Flu-like illness with spontaneous resolution
Pancytopenia
May extend to mediastinal LN
Granulomatous inflammation that mimics TB

51
Q

Discuss the features of chronic pulmonary histoplasmosis

A

May follow acute pulmonary OR latent lung infection
Cavitatory, coin lesions
Granulomatous, fibrosing mediastinitis
Resembles TB and malignancy
Epithelioid histiocytes
Caseous necrosis
IE
HLH

52
Q

Discuss the features of disseminated histoplasmosis

A

Immunocompromised patients
Extensive RES involvement
- lymphadenopathy
- HSM
- BM suppression
Oropharynx
Papulonodular mucocutaneous lesions that may ulcerate
Fever, cough, malaise, headache, weight loss

53
Q

What is the histopathology of histoplasmosis in immunocompetent patients?

A

Well-formed granulomata
Multinucleate giant cells
Caseous necrosis
Scanty organisms
Yeasts easily missed on H&E

54
Q

What is the histopathology of histoplasmosis in immunocompromised patients?

A

Histiocyte rich infiltrate
Numerous small intracellular yeasts
Neutrophils
Lymphocytes
Necrosis variable
Dot-like appearance
Refractile
Narrow-based budding

55
Q

Discuss the features of histoplasma var duboisii

A

Tendency for caseous and cutaneous involvement
Pulmonary disease unusual
Long and flat bones
Large multinucleate giant cells

56
Q

Which is larger: histoplasma capsulatum var capsulatum or var duboisii?

A

Var duboisii

57
Q

Which common yeast is mucicarmine positive?

A

Cryptosporidium

58
Q

In which patient population is mucormycosis most common in?

A

Diabetic ketoacidosis (rhinocerebral)

59
Q

What is the important feature of mucormycosis on histology?

A

Broad
Non-septate
Branch at 45 degrees

60
Q
A

DTMH Block 3 (18 decks)

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