Fungal respiratory infections Flashcards Preview

Year 1 Microbiology > Fungal respiratory infections > Flashcards

Flashcards in Fungal respiratory infections Deck (49):
1

Which fungal pathogens are associated with the sinuses?

Zygomycetes

2

Which fungal pathogens are associated with the lungs?

1. Histoplasma 2. Blastomyces 3. Paracoccidioides 4. Coccidioides 5. Cryptococcus

3

Which fungal pathogens are associated with the lungs of immunocompromised patients?

1. Pneumocystis 2. Aspergillus

4

What are predisposing factors to zygomycete infection?

1. Immunosuppresion 2. Diabetes 3. Burns

5

What are the properties of zygomycetes?

1. Non-septate hyphae 2. Sporangia bearing sporangiophores

6

What are the clinical symptoms of rhinocerebral zygomycosis?

1. Most common form of zygomycosis 2. Primarily in diabetic patients 3. Infection originates in sinuses 4. Extends to neighboring tissues 5. Initial symptoms look like standard sinus congestion 6. Can progress to periorbital area, brain

7

What is the diagnosis for zygomycoses (mucormycosis)?

1. Broad aseptate hyphae in blood vessels 2. Hyphae branch at 90 degrees

8

What is the treatment for zygomycoses (mucormycosis)?

Amphotericin B

9

How does candida present in normal flora?

Yeast

10

How does candida present in tissue?

Hyphal form

11

What is the clinical presentation for oral candidiasis?

1. Diffuse erythema and white patches on surface of buccal mucosa, throat, tongue, gums 2. Plaques can be scraped or wiped to reveal raw erythematous lesion 3. White lesions are composed of yeast and pseudohyphal forms of C. albicans

12

What is the treatment for oral candidiasis?

Oral formulations of nystatin and azole compounds

13

What are the properties of systemic mycoses?

1. Initially present as respiratory illness 2. Not opportunistic 3. Acquired by inhalation 4. Dimorphic forms are regional, C. neoformans is worldwide 5. All dimorphic except for C. neoformans (encapsulated yeast)

14

What pathogens are responsible for systemic mycoses?

1. Histoplasma capsulatum 2. Blastomyces dermatitidis 3. Paracoccidioides brasiliensis 4. Coccidioides immitis

15

What are the characteristics of histoplasmosis?

1. Endemic to Mississippi river valley and Ohio river valley 2. Caused by histoplasma capsulatum 3. Found in soil (bird and bat droppings) 4. Infection via inhalation of micro or macroconidia

16

What is the clinical syndrome of histoplasmosis?

1. Inhaled fungal spores are phagocytized by pulmonary macrophages and convert to their yeast form 2. Replicates within macrophages 3. Usually asymptomatic (95%)

17

What are the properties of histoplasmosis?

1. Mild flu like illness with dry cough, fever, fatigue 2. Develops several weeks after exposure 3. Improves in 2-3 weeks 4. Self limiting 5. Calcifications of pulmonary lesions common

18

What are the properties of chronic pulmonary and dissenminated histoplasmosis?

1. Typically in immunocompromised individuals 2. More life threatening than normal histoplasmosis 3. Fever, night sweats, anorexia, fatigue, respiratory symptoms 4. Hepatomegaly, splenomegaly, lymphadenopathy possible

19

What is the diagnosis for histoplasmosis?

1. Direct observation (difficult due to small size) 2. Culture (takes a long time) 3. Serology (detect Ab or Ag)

20

What is the treatment for histoplasmosis?

1. Amphotericin B for pulmonary and disseminated 2. AIDS patients: lifelong suppressive therapy with azoles

21

How can B dermatitidis be differentiated from H. capsulatum?

1. Size of yeast 2. Thickness of wall

22

What are the characteristics of blastomyces dermatitidis?

1. Dimorphic2. Yeast in tissues

23

What are the properties of blastomycosis?

1. Primarily pulmonary disease 2. Transmission via inhalation 3. Yeast survive in macrophages 4. Mostly asymptomatic

24

What are the clinical symptoms of blastomycosis?

1. Acute - cough, fever, chills, arthralgia, myalgia 2. Chronic pulmonary - cough, fever, night sweats, sputum production 3. Disseminated - skin lesion, bone infection, prostate involvement

25

What is the diagnosis for blastomycosis?

1. Observation of distinct yeast forms in sputum or biopsy 2. Long cultivation

26

What is the treatment for blastomycosis?

1. Amphotericin B 2. Azole compounds for uncomplicated pulmonary

27

What are the properties of paracoccidioidomycosis?

1. Limited to tropical south and central America 2. Caused by P. brasiliensis 3. High prevalence (90%) in men 4. Dimorphic 5. Ship's wheel and mickey mouse ear morphologies

28

What are the properties of coccidioides immitis?

1. Dimorphic 2. Arthroconidia easily airborne 3. Following inhalation fungus converts to spherule

29

What are the properties of spherules in coccidioides immitis?

1. Multinucleated 2. Produces hundreds of single nucleated spores

30

What are the clinical symptoms of coccidioidomycosis?

1. Asymptomatic 60% of the time 2. Mild to moderate flu like symptoms developing 1-3 weeks after infection 3. Self resolving 4. Chronic form may take years to resolve

31

What are the properties of disseminated coccidioidomycosis?

1. Rare2. Develops within 1 year of infection 3. Infection of bones, joints, skin, CNS

32

What are the properties of coccidial meningitis?

1. Develops slowly with increasing headache, fever, stiff neck, other neurological signs 2. Frequently fatal if untreated

33

What is the diagnosis for coccidioidomycosis?

1. Direct observation for spherule in sputum or biopsy 2. Cultivation 3. Serology

34

What is the treatment for coccidioidomycosis?

1. Azoles 2. Amphitericin B for disseminated and meningitis

35

What is the leading form of fungal meningitis?

Cryptococcal

36

What are the properties of cryptococcus neoformans?

1. Most common cause of cryptococcosis 2. NOT dimorphic 3. Encapsulated yeast

37

What are properties of pulmonary cryptococcosis?

1. Asymptomatic or mild, spontaneously resolving flu like sickness 2. Little sputum production 3. Little damage to lung (granuloma or cavitation)

38

What are properties of disseminated cryptococcosis?

Skin and bone lesions

39

What is the treatment for cryptococcal meningitis?

1. Long term (6-10 weeks) Amphotericin B + 5-fluorcytosine or fluconazole 2. Relapse is common in AIDS patients may require suppressive therapy

40

What are properties of pneumocystis jiroveci pneumonia (PCP)?

1. Caused by pneumocystis carinii (jiroveci) 2. Single celled eukaryote 3. Phylogenetically related to fungi 4. Some cellular and metabolic processes similar to protozoa 5. Difficult to grow in lab 6. Highly lethal

41

What are the clinical symptoms of PCP?

1. Infection via inhalation 2. Usually asymptomatic 3. Symptomatic - dyspnea, nonproductive cough, fever 4. Patient develops interstitial pneumonia with cellular infiltrate (weakness, tachypnea, cyanosis, death)

42

What is the diagnosis for PCP?

1. Identification in clinical material (lung lavage) 2. Need a special silver stain 3. Need to be looking for it and make special lab request

43

What is the treatment for PCP?

1. Trimethoprim-sulfamethoxazole - interferes with folate synthesis pathway 2. Prophylaxis in AIDS patients

44

What are the most common pathogens associated with aspergillosis?

1. A. fumigatus 2. A. flavus

45

What are the properties of aspergillosis?

1. Not dimorphic - always a filamentous mold 2. Infection via inhalation of conidia 3. Hyphal growth in tissues causes pathology

46

What are aspergillomas (fungus balls)?

1. Colonization of pre-existing lung lesions 2. Consist of hyphae within a matrix of fibrin and cellular debris 3. Typically unilateral 4. Frequently asymptomatic 5. Hyphal penetration of blood vessels results in hemoptysis

47

What are the properties of invasive / disseminated / systemic asperigillosis infection?

1. Occurs primarily in patients with leukemia, neutropenia, organ / marrow transplant 2. Frequently fatal 3. Invasion of lung parenchyma following infection 4. Hyphae invade vessel lumen causing thrombosis / infarction / hemorrhage 5. Dissemination from lung to GI, brain, liver, kidney

48

What is the diagnosis for aspergillosis?

1. Observation of hyphal elements in sputum or biopsy (septate hyphae with 45 degree V shaped branching) 2. Culture confirmation

49

What is the treatment for aspergillosis?

1. Azole 2. Echinocandin 3. Amphotericin B 4. Surgical removal of aspergillomas