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Micro U4 > Pulmonary Fungal Infection 2 > Flashcards

Pulmonary Fungal Infection 2 Flashcards

1
Q

What is the most important predisposition for susceptibility to opportunistic mycoses?

A

Prolonged Neutropenia

Underlying dz–determines severity

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2
Q

What are the five serotypes of Cryptococcus neoformans and gattii?

A

Neoformans–A, D and AD

Gattii–B and C

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3
Q

Where is cryptococcus neoformans found?

A

Environmental–found worldwide in soil contaminated with bird droppings—PIGEON

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4
Q

Where is cryptococcus gatti found?

A

Found in litter under eucalyptus trees

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5
Q

What is the structure of cryptococcus?

A

Oval yeast with narrow-based buds and wide polysaccharide capsule

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6
Q

When is cryptococcus strain pathogenic?

A

At 37 C

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7
Q

Is there human-to-human transmission of cryptococcus?

A

ONLY organ transplantation or needle stick–so in hospital

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8
Q

What has increased the caseload of cryptococcal meningitis?

A

Use of steroids
Survival with malignancy
AIDS

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9
Q

How is cryptococcosis transmitted?

A

Inhalation–pigeon droppings

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10
Q

How does cryptococcosis travel through body?

A

Either using macrophages or as a bare yeast because of thick capsule

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11
Q

Dissemination of cryptococcosis leads to?

A

Cryptococcal meningitis with SKIN Nodules

Seen mostly in AIDS pts

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12
Q

What causes the organ damage seen with C. neoformans?

A

Tissue distortion from growing yeast

Very little inflammatory response or granuloma formation occurs with neoformans

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13
Q

What are the virulence factors of cryptococcosis?

A

Capsule
Melanin in cell wall- antiphagocytic
Phospholipase B–allows tissue invasion

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14
Q

Why are fever and stiff neck less common with cryptococcosis meningitis?

A

Little inflammation involved with cryptococcosis infection

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15
Q

What complicates the dx of cryptococcosis infection?

A

Blunted inflammatory response–usually means pts present late in dz progression

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16
Q

What is used for assessment of the CSF with cryptococcosis infection?

A

India ink stain– observe yeast with wide capsule

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17
Q

What is used to stain a biopsy of cryptococcosis infection?

A

Methenamine silver
PAS
Mucicarmine

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18
Q

How is cryptococcosis cultured?

A

37C on Sabouraud agar

Will produce melanin in culture

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19
Q

What is crag in the context of cryptococcosis?

A

Serology–Latex agglutination for cryptococcal antigen in blood and CSF

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20
Q

What is Cryptococcomas

A

Focal neurologic defects

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21
Q

What is the tx for meningitis or cryptococcoma caused by cryptococcosis infection?

A

Amphotericin B plus flucytosine for 2 wks followed by 10 wks of fluconazole

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22
Q

What is the tx for cryptococcosis infection involving the prostate

A

Fluconazole

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23
Q

What is the tx for cryptococcosis infection involving the skin and bones?

A

Amphotericin B

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24
Q

When is it safe to stop tx for a cryptococcosis infection?

A

CSF needs to be examined weekly— must have consistently failed cultures to DC tx

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25
Q

What are the descriptive features of aspergillosis?

A

Mold–septate hyphae with V-shaped branches

26
Q

What are the 4 syndromes caused by aspergillosis?

A

Allergic bronchopulmonary aspergillosis
Aspergilloma or colonizing aspergilliosis: fungus ball in lung
Chronic necrotizing pulmonary aspergillosis
Invasive aspergillosis

27
Q

What is allergic bronchopulomnary aspergillosis?

A

HSR to infection of bronchi by aspergillus

Seen in asthmatic and CF pts

28
Q

What is Aspergilloma

A

Fungus ball formation when aspergillus invades cavitary pulmonary lesions of TB, CF

Hemoptysis is seen and can be life-threatening

29
Q

What is Chronic necrotizing pulmonary aspergillosis?

A

Seen in immunocompromised pts–invades lungs causing pneumonia with hemoptysis and granulomas (can have hyphae within granuloma)

High mortality rate

30
Q

What is invasive aspergillosis?

A

Rapidly progressive invasion of blood vessels in severely immunosuppressed pts

Involves infarction, hemorrhage, necorsis and is often fatal

31
Q

What are the Virulence factors of aspergillus?

A

Gliotoxin–immunosuppressive
Toxic metabolites interfere with phagocytosis and opsonization
Proteases–involved in tissue invasion

32
Q

Patient presents with positive skin test for aspergillus allergy and has a history of asthma or CF, coughing up brownish bronchial plugs containing hyphae, has fever, wheezing and pulmonary infiltrates that are NOT responsive to antibiotics and asthma/CF has been worse lately. Xray shows grape cluster of mucus-clogged bronchi. Dx?

A

Allergic bronchopulmonary aspergillosis

33
Q

Pt presents with fungus ball in lung on X-ray that changes position when pt sits up. Mass does not invade tissue. A air crescent sign is seen on CT of the lung. Dx?

A

Aspergilloma or colonizing aspergilliosis

34
Q

Pt presents with subacute pneumonia that is unresponsive to antibiotics. Pt has a history of COPD and has been on long-term steroid therapy. Has been on empiric tx for TB that has failed. dx?

A

Chronic pulmonary aspergillosis

Usually seen with underlying dz (alcoholism, collagen-vascular dz, chronic granulomatous dz, or COPD) and with long-term corticosteroid therapy

35
Q

Pt present with Hx of profound immunosuppression and COPD and is on corticosteroid therapy. Pt has fever, cough, dyspnea, pleuritic chest pain, neutropenia and hemoptysis. CT scan shows halo sign–ground glass infiltrate surrounding a nodular density. Dx?

A

Invasive aspergillosis

36
Q

How is a culture prepared for aspergillosis and what is seen?

A

Visualize with silver stains

See colonies with radiating chains of conidia that grows fast

37
Q

What are some defining features of aspergillosis?

A

Septate hyphae branching at acute angles invading tissue
Tissue necrosis
Blood vessel invasion

High serum levels of glactomannan antigen

38
Q

What are laboratory findings seen with allergic bronchopulmonary aspergillosis?

A

High levels of aspergillus-specific IgE and eosinophilia

Mucus with degenerating eosinophils and hyphae

39
Q

What is the tx for allergic bronchopulomnary aspergillosis?

A

Oral corticosteroids which is what causes the others

itraconazole

40
Q

What is the tx for aspergilloma?

A

Surgical removal if hemoptysis and oral itraconazole

41
Q

What is the treatment for invasive or Chronic necrotizing pulmonary aspergillosis?

A

Voriconazole and/or amphotericin B

Decrease immunosuppression if possible

High mortality

42
Q

What are the underlying risk factors for Mucormycosis (Rhizopus) infection?

A

DM

Neutropenia

43
Q

How is mucormycosis (Rhizopus) transmitted?

A

Airborne asexual spores

Inhaled or ingested/introduced by trauma

Invades tissues of pts with reduced immunity–DM, Burns, Leukemia, IV steroids or TNF blockers, iron overload

44
Q

What cells are the main host defense against mucormycosis (Rhizopus)?

A

Neutrophils

45
Q

What is seen with mucormycosis (Rhizopus) infection when involving rhino cerebral area?

A

Unilateral retro-orbital HA
Facial pain
Numbness
Fever

Progresses to:

  • Diplopia and visual loss
  • Reduced consciousness
  • Black pus
  • Necrotic eschars
46
Q

What is seen cutaneously with a mucormycosis (rhizopus) infection?

A

cellulitis progressing to dermal necrosis and black eschar formation

47
Q

What is seen on blood work of a patient with mucormycosis (rhizopus) infection?

A

Neutropenia
Diabetic acidosis
Iron overload

48
Q

What is seen on biopsy of mucormycosis (Rhizopus)?

A

Nonseptate hyphae with broad irregular walls and branches at right angles

Vascular invasion and necrosis with neutrophil infiltration

49
Q

What is seen on a culture of mucormycosis (rhizopus)?

A

colonies with spores contained in sporangium

50
Q

What is the tx for mucormycosis (rhizopus) infection?

A

If dx early tx underlying disorder and amphortericin B and aggressive surgical removal of necrotic tissue

Very high mortality rate

51
Q

What is unique under the microscope about fusarium?

A

Banana–shaped marcoconidia

52
Q

What are the virulence factors for fusarium mycology?

A

Immunosuppressive mycotoxins
Collagenases and proteases
Ability to adhere to prosthetic material

53
Q

What are the 3 presentations seen with fusarium?

A

Mycotoxicosis
Immunocompetent local infection
Immunosuppressed opportunistic infection

54
Q

What is seen with mycotoxicosis caused by fusarium?

A

Widespread bleeding and immunosuppression with secondary sepsis–often fatal

55
Q

What is seen with immunocompetent local infection caused by fusarium infection?

A

Seen with burns and contaminated contact lens solution–skin and cornea involved

Allergic sinusitis
Colonization of prosthetics and catheters

56
Q

What is the tx for immunocompetent local infection caused by fusarium infection.

A

Amphotericin B
Voriconazole
Posaconazole

57
Q

What are the predispositions exposing pts to an opportunistic infection caused by Fusarium?

A

Prolonged neutropenia
Long-term use of steroids
Profound T-cell deficiency (HSCT recipients)

58
Q

What causes a disseminated fusarium infection and how does it present?

A

Invasion from sinus or wound site

Presentation:
-Fungemia with skin lesions that invaded from within the skin!!

59
Q

What complicates culturing of fusarium?

A

Grow very easily on media BUT is environmentally ubiquitous so MANY samples and sites are need to differentiate from lab contamination

60
Q

What is used for the prevention of Fusarium infection?

A

High-risk pts kept in HEPA filtered rooms at POSITIVE pressure with filtered water supplies and scrubbed-down showers

Micro U4 (9 decks)

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