Tuberculosis

Question 1

classification of mycobacteria

Answer 1

M. leprae- leprosy (Hansens Disease)

M. tuberculosis

non-tuberculosis mycobacteria (NTM)

Question 2

mycobacterium gram stain and morphology

Answer 2

weakly positive rods

Question 3

mycobacterium motility

Answer 3

non motile

Question 4

mycobacterium spores

Answer 4

non spore forming

Question 5

mycobacterium capsule

Answer 5

no capsule

Question 6

mycobacterium cell walls

Answer 6

contain fatty acids- absent in most other

Question 7

mycobacterium acid fastness

Answer 7

stain with ziehl neelsen procedure, making them appear red

Question 8

TB transmissoin

Answer 8

person to person by inhalation

ingested by alveolar macrophages and induce granuloma formation in the lung (rarely brain liver or kidney)

may cause transient bacteremia

may stay latent for years before transitioning to a TB disease

Question 9

TB syndromes

Answer 9

ghon lesion, ghon complex, and ranke complex- seen on imaging

cavitary TB- hole in the lung from TB damage, containing large number of bacteria

miliary TB- occurs throughout the entire lung and potentially whole body

extrapulminary TB- miliary, lymphatic, skeletal, or any non lung site

Question 10

TB and HIV`

Answer 10

leading opportunistic infection of HIV infected pts b/c it is CD4 cell mediated immunity that is compromised in HIV

Question 11

diagnosing active TB

Answer 11

acid fast bacillus smear- same day results but limited sensitivity and specificity

culture- takes more time but more sensitive

nucleic acid ampliciation- fast

Question 12

TB treatment

Answer 12

isonizaid- cidal for extracellular, causes hepatitis and neuropathy

rifampin- cidal for intracellular, causes hepatitis and influenza syndrome

pyrazinamide- intracellular, causes GI, hepatitis, and rash

ethambutol- static, causes optic neuritis, rash

RIPE for 2 months, then INH/rifampin for 4 months

Question 13

multidrug resistance to TB

Answer 13

resistance to INH and rifampin

treatment is expensive and takes years

Question 14

diagnosis of latent TB

Answer 14

PPD- delayed hypersensitivity test

TB contact or HIV- greater than 5

for immigrant, drug user, hospital worker, or diabetic- greater than 10

for persons w/o risk- greater than 15

Question 15

IGRAs

Answer 15

interferon gamma release assats- blood assay for TB

mononuclear cells from pts w/ TB infection and normal T cell immunity prouce IFN in response to TB Ags

Question 16

treatment for latent TB

Answer 16

INH for 9 months

rifampin for 4 months

Question 17

mycobacterium bovis

Answer 17

related to TB, causes TBs in cows and milk can cause GI “TB” in humans- attenuated strain is source of vaccine for TB

works well in children

can cause positive PPD tests

Question 18

mycobacterium leprae is special because…

Answer 18

cannot be cultivated in vitro

obligate intracellular

Question 19

mycobacterium leprae pathophysiology

Answer 19

likes cooler temps- skin, nose, upper respiratory tract

armidillos are other host

respiratory transmission

incubation period is 2-5 years

Question 20

differences between TB and leprosy

Answer 20

TB- granulomas, few bacteria, cellular immune rxn, lepromin skin test positive, good prognosis

lepsory- few granulomas, many bacteria, nodules and diffuse thickening, Ab immune rxn, negative lepromin skin test, poor prognosis

Question 21

leprosy diagnsosi

Answer 21

appearance of lesions and acid fast stains

Question 22

treatment of leprosy

Answer 22

chemotherapy- dapsone, rifampin, clofazimine

Question 23

nonTB mycobacteria transmission

Answer 23

not human to human

found in soil, water, animals

Question 24

runyon classification

Answer 24

classification of nonTB mycobacteria based off how fast they grow and whether they express color in light or dark

Question 25

mycobacterium avium

Answer 25

most common NTM in US

found in water soil and birds

Question 26

mycobacterium avium syndromes

Answer 26

cervical adenitis in children

pulmonary disease in pts w/ chorninc lung disease

pulmonary disease in normal hosts

disseminated infection in AIDS

treatment takes 18 months