lecture 30- Bacterial infections of the lower respiratory tract III

Question 1

mycobacteria
gram stain-
cell wall
contents that would let you know it was mycobacteria

Answer 1

gram positive- acid fast
cell wall = lipid rich- responsible for acid fast staining
arabinogalactam, lipoarabinomannin, mycolic acid peptidoglycan

Question 2

how many animals can be infected by the mycobacterium tuberculosis

Answer 2

• just humans

Question 3

how many states are there of TB

Answer 3

-4- active, latent, primary, reactivation

Question 4

how does TB infect

Answer 4

enters thru respiratory tract and goes into alveoli of the lungs
macrophages and lymphocytes come to kill it but can’t so a wall of cells is formed around it by CD4 and CD8 and NK cells causing ‘caseaous necrosis’ that looks like white cheese

Question 5

latent TB

Answer 5

-when granuloma forms around TB and there is no spread

Question 6

primary TB?
when does it become reactivated?
activated?

Answer 6

• usually asymptomatic- leads to clearance
• in normal people- it only becomes “reactivated” when an immunocompromising event occurs
• active when pt is immunocompromised

Question 7

why is cell mediated immunity a dual edged when it comes to TB

Answer 7

-because CD8,4 and nk cells form a granuloma around TB and that’s the end of it
UNLESS
you have inadequate control and get active or reactivation of TB where most damage is ACTUALLY THE CELL MEDIATED IMMUNITY CAUSING NECROTIC LESIONS AND INFLAMMATION OF THE TISSUES

Question 8

disseminated TB infection

Answer 8

• known as military TB (looks like millet seeds) aka extrapulmonary TB - where TB is outside of the lungs
• granulomas form anywhere

Question 9

symptoms of primary TB
active
reactivation

Answer 9

primary- asymptomatic
active-gradual onset, variable, fatigue, weight loss, fever, night sweats, chest pain, dyspnea, cough WITH YELLOW OR YELLOW GREEN OR BLOOD STREAKED SPUTUM
reactivation- when granulomas fall apart and Mtb moves or is aerosolized (transmittable up to 2-3 yrs)-symptoms same as active TB

Question 10

ghon complex

Answer 10

-lung lesion (granuloma calcified) PLUS calcification of affected HILAR lymph seen on an xray

Question 11

how do you distinguish between active and reactivated TB

Answer 11

• lab tests, chest xray that will show granulomas that had already formed if it’s a reactivated state plus a cavity formation usually in the upper lobes of both lungs

Question 12

ghon focus

Answer 12

-just calcification of granuloma in lung of chest xray

Question 13

lab tests for TB

Answer 13

• skin test- purified protein derivatives (PPD)
• IFN-gamma release assay- check it’s release by t cells in whole blood stimulated by mtb =used for pt BCG vaccinated
• can use acid fast staining but that just says that you have mycobacterium not exactly TB
• PCR (expensive)
• culture (slow/contamination)- on sputum

Question 14

treatment of TB

Answer 14

• 4 drug cocktail: ethambutol, pyrazinamide, isoniazid, and rifampin = for two months followed by 26 months of INH and rifampin
• pt must take it somewhere because side effects are awful

Question 15

what is the vaccine for TB and where is it used? what’s the downfall?

Answer 15

• BCG vaccine
• used everywhere besides US and Netherlands
• downfall- pos TB skin test

Question 16

mycobacterium avium-intracellulare

Answer 16

• complex of mycobacteria

- pulmonary infection resembling TB in immuocompromised peeps or peeps with lung disease

Question 17

mycobacterium kansasii

Answer 17

-elderly
chronic grandulomatous pulmonary disease seen in COPD pt
(when you get older you get saucy)