Tuberculosis

Question 1

CXR findings in early stage of TB

Answer 1

Ghon focus/coin lesion in the lungs

Question 2

Stains for Mycobacterium tuberculosis

Answer 2

Acid-fast staining/Ziehl-Neelsen
Fluorescent staining

Question 3

Reason for acid-fast property of Mycobacterium tuberculosis

Answer 3

Mycolic acids in cell wall

Question 4

Appears pink on blue background in acid-fast stain

Answer 4

Mycobacterium

Question 5

Fluorescent staining of Mycobacterium

Answer 5

Screen with auramine-rhodamine, appears apple green

Question 6

Mediums for culture of Mycobacterium tuberculosis

Answer 6

Lowenstein-Jensen Agar - slow growth
Bactec liquid medium - faster growth

Question 7

MDR TB

Answer 7

Disease with bacillary resistance to isoniazid and rifampicin

Question 8

XDR TB

Answer 8

Bacillary resistance to isoniazid, rifampicin, fluoroquinolone, and at least one injectable (kanamycin, amikacin, capreomycin)

Question 9

Virulence factor of TB that contributes to resistance of killing in macrophages and the ability to remain latent within macrophages

Answer 9

High lipid content

Question 10

Cord factor of Mycobacterium tuberculosis that causes serpentine growth

Answer 10

Trehalose dimycolate

Question 11

Soluble virulence factors of Mycobacterium tuberculosis

Answer 11

Superoxide dismutase
Catalase

Question 12

Virulence factor of Mycobacterium tuberculosis that blocks phagosome-lysosome fusion

Answer 12

Sulfatides

Question 13

Complement receptors of M tuberculosis

Answer 13

CR1, CR2, CR3, CR4

Question 14

Transmembrane protein of endosomes and lysosomes that has different polymorphism that can cause progression of TB without an effective immune response

Answer 14

NRAMP1

Question 15

Function of NRAMP1

Answer 15

Pumps iron out to inhibits bacterial growth by limiting availability of iron

Question 16

Step 1 - initial infection of TB

Answer 16

Infection of macrophages by M tuberculosis followed by unchecked replication and blocking or phagolysosome formation

Question 17

Step 2 of TB infection

Answer 17

TH1 response to activate macrophages, allowing macrophages to become bactericidal

Question 18

Step 3 of TB infection

Answer 18

TH1 mediated macrophage activation and killing of bacteria

Question 19

Critical mediator that enables macrophages to contain TB infection. Stimulates maturation of phagolysosome, production of NO, autophagy, and mobilizes antimicrobial peptides (defensins)

Answer 19

IFN-gamma

Question 20

Peripheral rim of epithelioid histiocytes surrounding a central necrotic region that is dry, crumbling, and cheesy

Answer 20

Caseating granulomas

Question 21

External to rim of histiocytes of caseating granulomas

Answer 21

Outer rim of lymphocytes and plasma cells

Question 22

Miliary TB

Answer 22

Invasion of blood vessels and dissemination throughout the body

Question 23

CD4 count at risk for Mycobacterium avium intracellulare

Answer 23

<50

Question 24

Transmission of MAC

Answer 24

Inhalation of contaminated water or ingestion, not person to person

Question 25

Prophylaxis for MAC

Answer 25

Azithromycin
Clarithromycin
Rifabutin

Question 26

Treatment for MAC

Answer 26

Combination of 4 drugs:
Clarithromycin or azithromycin
Ethambutol
Rifabutin
Amikacin or fluoroquinolone

Question 27

Acid-fast stain that does not require heat

Answer 27

Kinyoun

Question 28

Weak acid-fast branching bacilli that can cause cavitary bronchopulmonary necrosis

Answer 28

Nocardia asteroides

Question 29

Nocardia species that has a cutaneous manifestation

Answer 29

N brasiliensis

Question 30

Treatment of choice for Nocardia

Answer 30

Sulfonamides