Fungal and Immunocompromised Pneumonia Flashcards Preview

Pulmonary Week 2 > Fungal and Immunocompromised Pneumonia > Flashcards

Flashcards in Fungal and Immunocompromised Pneumonia Deck (72):
1

What are the types of fungal infections?

-superficial and cutaneous mycoses
-subcutaneous (skin, lymphatics, subQ tissue)
-Endemic mycoses
-Oppoertunistic mycosis

2

What causes endemic mycoses?

dimorphic fungi

3

Notes about dimorphic fungi

-most common etiologic agents of pulmonary infection by fungi

-infection results from inhalation of spores that mold forms in soil

4

What does 'dimorphic' mean?

-grow as yeast in human tissue and as mold at room temp

5

What happens with spores of dimorphic fungi are inhaled?

they differentiate into yeasts or spherules. Most are self-limited but all can cause pneumonia and disseminate

6

What are some dimorphic fungi?

-Blastomyces dermatitidis
-Histoplasma capsulatum
-Coccidioides immitis
-Paracoccidioides brasiliensis

7

Where is Histoplasma capsulatum endemic?

Mississippi and Ohio River

8

Where does Histoplasma capsulatum grow?

soil and bird droppings

9

How does Histoplasma capsulatum infection present?

-mostly asymptomatic pulmonary infection
-but can have fever, chills, cough, chest pain

10

In AIDS, Histoplasma capsulatum can disseminate. What organs are typically affected?

-BM (pancytopenia)
-Mouth/Gi (ulcers)
-Skin (rash, nodules)

11

Tissue biopsy of positive Histoplasma capsulatum will show what?

oval yeast cells within macrophages

12

How else can Histoplasma capsulatum be diagnosed?

-serology
-Urinary antigen (good for AIDS patients)

13

How does Histoplasma capsulatum show on CXR?

-infiltrates
-mediastinal LAD
-cavitary lesions

14

What are two possible skin manifestations of Histoplasma capsulatum infection?

-skin rashes
-erythema nodosum

15

Note about skin rashes in Histoplasma capsulatum

seen in disseminated Histo (rash is rare, but common in AIDS/immunocompromised)

16

What is erythema nodosum?

tender nodules that present on extensor surfaces (tibia and ulna skin). Result from delayed hypersensitivity response to fungal antigen and is an indicatory of poor prognosis (not specific to histo but also seen in coccidioides and TB)

Aka desert bumps

17

Where is Blastomyces dermatitidis endemic?

Ohio/Mississippi River Valley, Missouri, and Arkansas River basins (grows in moist soil)

18

How does Blastomyces dermatitidis present?

asymptomatic respiratory illness, 50% will have cough, chest pain, sputum, fever/night sweats

most resolve spontaneously

19

Disseminated Blastomyces dermatitidis results in what?

ulcerated granulomatous lesions of the skin (70%), bone (33%), GI tract (25%), and CNS (10%). Seen in both immunocompetent and compromised patients

20

What does tissue biopsy of Blastomyces dermatitidis show?

thick-walled yeast cells with **single broad-based bud**

21

How is Blastomyces dermatitidis diagnosed?

-CXR (lobar consolidation)
-tissue biopsy
-serology

22

How is Histoplasma capsulate treated?

Ampho B for severe and Itra otherwise

23

How is Blastomyces dermatitidis treated?

Ampho B for severe and Itra otherwise

24

Where is Coccidioides immitis endemic?

Southwest and Latin America

25

Describe the pathogenesis of Coccidioides immitis

In the lungs, large spherules form and filled with endospores. Upon rupture, endospores are released and differentiate into new spherules

26

How does Coccidioides immitis present?

-mild flu-like illness with fever and cough ('valley fever') in 10%
-erythema nodosum

27

How common is dissemination in Coccidioides immitis?

1% (to bone, meninges, and skin)

28

What ethnicities are at increased risk for dissemination of Coccidioides immitis?

-AA, Filipinos, and women in 3rd trimester

29

____ is common with Coccidioides immitis

Eosinophilia

30

How is Coccidioides immitis treated?

-Ampho for persistent lung lesions or disseminated

-Fluconazole for meningitis

31

Where is Paracoccidioides brasiliensis endemic?

rural latin america, especially brazil

32

How does Paracoccidioides brasiliensis present?

mild respiratory infection which can disseminate and develop oral, nasal, and facial nodular ulcerated lesions and submandibular LAD

33

How is Paracoccidioides brasiliensis diagnosed?

-tissue biopsy shows yeast cells with multiple buds (aka pilot well configuration)
-Serology

34

Treatment of Paracoccidioides brasiliensis?

-several months of Itra
-Ampho for severe

35

Where is Aspergillus fumigatus found and how does it exist?

worldwide in a mold with ACUTE branching septate hyphae that grows on decaying vegetation producing chains of conidia

36

Features of Aspergillus fumigatus infection.

-fungus ball formed within cavities of lungs (can produce hemptysis)

-allergic infection of bronchi that produces asthmatic symptoms and high IgE titer

-invasive PNA with hemorrhage, infarction, and necrosis

37

What patient population is especially at risk for invasive PNA form of Aspergillus fumigatus?

those with hematologic malignancies and neutropenia

38

How does Aspergillus fumigatus present upon CT?

Can have single or multiple nodules with cavitation and a a ’halo’ sign which are areas of focal hemorrhage around a lesion

39

How is Aspergillus fumigatus treated?

-**Voriconazole** for invasive disease (ampho B and echinocandins alternatives if not well-tolerated)

-remove fungus balls

40

What is the treatment for ABPA?

steroids and antifungals

41

Describe Mucormycosis

Opportunistic infections caused by bread mold fungi (Mucor, Rhizomes, Cunninghamella, Lichtheimia)

42

What are some risk factors for Mucormycosis?

-diabetes
-neutropenia
-Iron excess
-burns/surgical wounds
-corticosteroid use

43

How is Mucormycosis transmitted?

airbourne spores that invade tissue and blood in those with reduced host defenses

44

How does Mucormycosis present?

-invasive rhinocerebral sinusitis
-frontal lobe abscesses
-pneumonia
-cutaneous infection

45

How does invasive rhinocerebral sinusitis occur?

originates in the paranasal sinuses and spreads to the orbit, hard palate, and brain and carries a high mortality rate

46

How is Mucormycosis diagnosed?

tissue biopsy with nonseptate broad hyphae with frequent RIGHT ANGLE branching; spores in a sporangium

47

How is Mucormycosis treated?

treat underlying disorder + Ampho and surgical removal of necrotic tissue

Alternative: Poscaonazole

48

How does Pneumocystis jiroveci exist?

yeast

49

Pneumocystis jiroveci is the most common cause of ___ in immunocompromised patients

pneumonia

50

Pathogenesis of Pneumocystis jiroveci (PCP)

cysts in alveoli produce inflammation, resulting in frothy exudate that block oxygen exchange (organism does not invade lung tissue)

51

How is Pneumocystis jiroveci cleared?

CD4 T cells recruit monocytes and macrophages which clear the organism (thus, AIDS is a major risk factor)

52

How does Pneumocystis jiroveci present?

-Dry cough, progressive dyspnea
-fever
-tachypnea, hypoxemia

53

CXR of PCP

-pneumothorax
-bilateral infiltrates

54

How is PCP diagnosed?

-Cysts in lung biopsy or from bronchoscopy fluids
-fluorescent AB staining
-PCR on RT specimens

55

How are cysts identified from PCP?

methenamine silver, Giemsa stain

56

How is PCP treated?

-Cotrimoxazole (Bactrim) (1st line)

57

2nd line options for PCP

-Clindamycin/Primaquine
-Atovaquone
-Pentamidine

58

Prophylaxis for AIDS patients with CD4 count below 200?

Bactrim, Dapsone, or Atovaquone

59

How does Cryptoococcus neoformans exist?

yeast in soil and PIGEON droppings that has the appearance of oval budding yeast with a wide polysaccharide capsule

60

What disease does Cryptoococcus neoformans cause?

meningitis in immunocompromised (especially in AIDS)

AND

PNA in immunocompromised AND competent persons

61

How does Cryptoococcus neoformans induced PNA present in immunocompetent persons?

asymptomatic or mild respiratory symptoms

62

How does Cryptoococcus neoformans induced PNA present in immunocompromised persons?

fever, chest pain, dyspnea, cough, and hemoptysis

63

T or F. CMV is a herpes virus

T.

64

How does CMV exist in the body?

enters latent state primarily in monocytes and can be reactivated when cell-meidtaed immunity is decreased

65

What patients is CMV commonly reactivated?

-renal and stem cell transplant recipients
(pneumonitis results)

66

What does activation of CMV in AIDS patients cause?

colitis and retinitis (typically NOT pneumonitis)

67

Two buzz words with CMV

ground glass appearance and inclusion bodies on H&E

68

What causes Nocardiosis?

Nocardia asteroides

69

Describe Nocardia asteroides

gram+ aerobe found in soil with thin branching filaments

70

In immunocompromised patients, Nocardia asteroides can disseminate and has a predilection for ____

brain tissue (can cause brain abscesses)

71

How is Nocardiosis diagnosed?

gram stain/acid-fast stain; culture

72

Treatment of Nocardiosis

Cotrimoxazole (resistance common- check susceptibilities)