TB, mycobacteria, atypical

Question 1

mycobacteria is NOT

Answer 1

mycoplasma that causes walking pneumonia

Question 2

what are the 2 major species of Mycobacterium?

Answer 2

1. Mycobacterium tuberculosis

2. Mycobacterium leprae

Question 3

Mycobacteria gram stain

Answer 3

very poorly, but are almost uniquely acid-fast

Question 4

what are the important structural components of M. tuberculosis?

Answer 4

1. mycolic acids –> acid fastness
2. Wax D
3. Phosphatides –> caseation necrosis
4. cord factor (trehalose dimycolate) –> virulence, microscopic serpentine appearnce

Question 5

what structural component of TB cause lung pathogenesis?

Answer 5

phtiocerol dimycocerosate

Question 6

what is the cord factor of TB?

Answer 6

trehalose dimycolate

Question 7

M. tuberculosis do not produce any

Answer 7

toxins

Question 8

M. tuberculosis can be either

Answer 8

intra or extracellular

Question 9

what important structural component is associated with lung pathogenesis?

Answer 9

phtiocerol dimycocersosate

Question 10

M tuberculosis proliferates within

Answer 10

mononuclear phagocytes, traveling to extrapulmonary sites, where it can establish latent (immunocompetent) or active (peds, HIV+, immunosenescence) extrapulmonary infeciton:

1. lymph nodes
2. kidney
3. bones
4. meninges

Question 11

what result in infecting GI?

Answer 11

swallowing infectious sputum

Question 12

what terminates the unimpeded growth of the M. tuberculosis 2-3 weeks after initial infection?

Answer 12

cell mediated immune response

Question 13

CD4 helper T cells activate

Answer 13

some infected macrophages to kill intracellular bacteria

Question 14

CD8 suppressor T cells lyse other infected macrophages leading to

Answer 14

caseating granulomas = tubercules

Question 15

mycobacteria cannot continue to grow within these

Answer 15

granulomas, so the infectious pauses (latency)

Question 16

what plays an important role in maintaining latency?

Answer 16

TNF (pts getting TNF-a antagonists may reactivate)

Question 17

what is the most common site of the primary lesion of TB?

Answer 17

within alveolar macrophages in subpleural regions of the lung

Question 18

Bacilli proliferate locally and spread through the lymphatics to a hilar node, forming the

Answer 18

Gohn complex, launch from there to the bloodstream

Question 19

what is ghon complex?

Answer 19

typical of pulmonary tuberculosis, consists of a parenchymal focus and hilar lymph node lesions

Question 20

Ghon complex

Answer 20

exudative lesion plus hilar node

Question 21

what are the classic active pulmonary TB’s clinical symptoms?

Answer 21

1. presents with cough
2. weight loss = consumption
3. fever
4. night sweats
5. hemoptysis
6. chest pain

Question 22

what is TB scrofula?

Answer 22

reactivation in lymph node

–> painless, enlarging, or persistent mass

Question 23

what is the most common site for extrapulmonary infection?

Answer 23

genitourinary TB (usually secondary to renal tuberculous infection)

Question 24

what is miliary TB?

Answer 24

hematogenous spread of TB throughout body, many tiny noncalcified foci of infection appear “like millet seeds” in lung on chest X ray

Question 25

what are some clinical characteristic of miliary TB?

Answer 25

1. Hx of cough and resp distress 2. lymphadenopathy 3. hepatosplenomegaly 4. tachypnea 5. cyanosis

Question 26

what are the clinical signs of TB meningitis?

Answer 26

1. 5-10% of children younger than 2 yrs 2. nuchal rigidity 3. altered deep tendon reflexes 4. lethargy 5. cranial nerve palsies