Micro Pulmonary fungal infections 2

Question 1

what are the major opportunistic mycoses?

Answer 1

candida, cryptococcus, aspergillus, mucor/rhizopus, fusarium spp

Question 2

cryptococcus form

Answer 2

oval, budding yeast that is NOT thermally dimorphic

Question 3

cryptococcus transmission

Answer 3

environmental (worldwide in soil contaminated with bird droppings esp pigeon) - no human to human

Question 4

pathogenesis of cryptococcus

Answer 4

inhalation, lung infection that could lead to pneumonia, immunosuppression for dissemination which has meningitis with skin nodules

Question 5

what is characteristic for cryptoccocus

Answer 5

skin nodules and blunted inflammatory response to infection

Question 6

virulence factors for cryptoccocus

Answer 6

1. capsule (not eaten by macrophage)
2. melanin in cell wall (anti-phagocytic)
3. phospholipase (break down tissue to help invade)

Question 7

lab for cryptococcus

Answer 7

• CSF: stain with India ink - years with wide capsule

- serologic test: crag for cryptococcal antigen

Question 8

treatment for cryptococcus

Answer 8

amphotericin B PLUS flucytosine

in AIDS: fluconazole for long-term suppression

Question 9

aspergillus form

Answer 9

only mold, not dimorphic

septate hyphae with V shaped brances

Question 10

pathogenesis aspergillus

Answer 10

widespread on decaying vegetation worldwide, infectious conidia are airborne which colonize skin, burns, cornea, ear sinuses

Question 11

aspergillus virulence factors

Answer 11

gliotoxin (immunosuppressive), toxic metabolites, proteases

Question 12

what are the four presentations of aspergillus

Answer 12

1. allergic bronchopulmonary aspergillosis (ABPA): hypersensitivity to infection of bronchi by aspergillus - exacerbates asthma, cystic fibrosis
2. aspergilloma: “colonizing aspergilliosis” - fungus ball in vaitary lesion left by past TB, etc
3. chronic necrotizing pulmonary aspergillosis (CNPA): hyphae invade lung tissue causing pneumonia with hemoptysis and granulomas
4. invasive aspergillosis: rapidly progressive invasion of BV leading to infarction, hemorrhage, necrosis

Question 13

diagnosis of ABPA

Answer 13

coughing up BROWNISH BRONCHIAL PLUGS containing hyphae, allergic to aspergillus, underlying asthma or CF
-X-ray/CT may show grape cluster (clusters of mucus clogged bronchi)

Question 14

aspergilloma diagnosis

Answer 14

fungus ball visible on X-ray, changes position when patient sits up/lies down. cough, fever, leading to dangerous hemoptysis

Question 15

CNPA diagnosis

Answer 15

subacute pneumonia unresponsive to antibiotics with fever, cough, night sweats, weight loss
history of alcoholism, collagen-vascular disease, chronic granulomatous disease, COPD, long-term corticosteroids
-hard diagnosis - best sample is aspirate of fluid from lungs

Question 16

Invasive aspergillosis diagnosis

Answer 16

history of profoudn immunosuppression or COPD with long-term corticosteroids. fever, cought, pleuritic chest pain
-CT scan has characteristic “halo sign” (focus of pulmonary infarction surrounded by alveolar hemorrhage)

Question 17

biopsy for aspergillosis

Answer 17

• septate hyphae invading tissue at acute angles
• cultures have colonies with radiating chains of conidia
• invasive: high serum levels of glactomannan antigen
• ABPA: aspergillus-specific IgE, eosinophilia, hyphae in mucus

Question 18

treatment of ABPA

Answer 18

oral corticosteroids and itraconazole, sinus surgery

Question 19

treatment of aspergilloma

Answer 19

remove surgically and oral itraconazole

Question 20

CNPA/invasive treatment

Answer 20

amphotericin B, lipsomal if kiney issues, surgical resection

Question 21

mucor/rhizopus form

Answer 21

mold form - not dimorphic

Question 22

pathogenesis rhizopus/mucor

Answer 22

airborne asexual spores, invade tissues patients w/ reduced immunity ESP diabetes, burns, leukemia, proliferate in walls of BV esp paranasal sinuses, lungs, gut, cause infarction and necrosis of tissue downstream of blocked vessel

Question 23

what are the two characteristic things about mucor/rhizopus?

Answer 23

DIABETES and paranasal sinuses

Question 24

symptoms of mucor/rhizopus

Answer 24

brain, eyes, lungs, skin, GI, CNS (due to imparied blood flow

Question 25

labs for mucor/rhizopus

Answer 25

• biopsy: nonseptate hyphae with broad irregular walls and branches at right angles
• cultures: colonies with spores contained in sporangium - difficult to culture

Question 26

treatment for mucor/rhizopus

Answer 26

50% mortality - needs to be dianosed early

-amphotericin B and surgical removal of necrotic tissue

Question 27

fusarium spp from what?

Answer 27

primarily pathogens of plants including improtant crops

Question 28

how does fusarium spp cause disease?

Answer 28

1. mycotoxicity (toxins, no actual fungus)
2. immunocompetent patients = local infection common in burn unit
3. immunocompromised patients = aggressive disseminated infection

Question 29

pathogenesis of disseminated infection of fusarium spp

Answer 29

airborne conidia also has inhalation of water - causes local infections and locally invasive infections depending on immune status

Question 30

virulence factors for fusarium spp

Answer 30

immunosuppressive mycotoxins, collagenases and proteases, ability to adhere to prosthetic material (similar to asperilligus but less pathogenic)

Question 31

what are the systems commonly affected by fusarium spp?

Answer 31

eye (corneal infection), sinuses (allergic sinusitis), pneumonia, skin lesions (wound sites in immunocompetent, anywhere for immunocompromised), fungemia

Question 32

diagnosis for fusarium spp

Answer 32

• samples from several sites on fungal media - banana-shaped macroconidia with “foot cell” at the base
• has BOTH a mold and yeast form

Question 33

treatment of fusarium spp

Answer 33

more resistant to antifungals - need surgical care and topical/oral antifungals (natamycin or coriconazole)
-amphotericin B for disseminated disease

Question 34

prevention of fusarium spp

Answer 34

HEPA-filtered rooms at positive pressure (keep dust out)