Tuberculosis

Question 1

describe mycobacterium tuberculosis

Answer 1

aerobic and anaerobic
extra and intracellular
multidrug resistance
slow growing, latent

Question 2

describe the pathophysiology of Tb

Answer 2

very communicable spreads easily
aerosolized droplets
enter the bronchials then alveoli and settle in lower lobe
first line macrophage immunity followed by t cell over 2-8wks

Question 3

risk factors for exposure

Answer 3

close contacts 
endemic areas - northern ca 
poor living conditions, crowded, correctional facilities 
health care workers 
homelessness

Question 4

results of tests in latent TB

Answer 4

negative xray, sputum stain and culture

Question 5

symptoms of latent TB

Answer 5

asymptomatic
spreads to regional lymph nodes
latent or dormant in seeded foci (ghon node) for months - years
NOT CONTAGIOUS

Question 6

how does tst test work

Answer 6

heat sterilized protein derivative

delayed hypersensitivty response delayed 48-72hrs

Question 7

what can cause false negatives

Answer 7

cutaneous anergy (absence of an IR to an antigen) 
preconversion 
neonate
elderly 
HIV
chemo 
lymphoma 
corticosteroids 
** use positive control mumps or candida

Question 8

tst does not distinguish latent from what

Answer 8

active TB
BCG vaccination
other mycobacterial infection

Question 9

interferon gamma assay

Answer 9

blood test measures t cell release of interferon gamma

does not distinguish from active disease but most specific with patients vaccinated with BCG

Question 10

TST result <4mm indicates

Answer 10

negtive result

Question 11

TST result >/=5

Answer 11

positive in certain people 
HIV 
exposure in past 2 years 
fibronodular disease on chest xray 
ESRD 
therapy with immunosuppressants

Question 12

TST result >10

Answer 12

TST conversion within 2 years

Question 13

when should you treat latent TB how effective is it

Answer 13

90% effective
only if exposure to infectious TB wihtin the previous 2 years
assess risk vs benefit

Question 14

standard latent TB therapy

Answer 14

isonazid daily for 9 months

Question 15

alternative latent tb therapy

Answer 15

isonazid 6 months
isonazide/rifampin 3mon
rifampin 4 months

Question 16

when does primary tb occur

Answer 16

early within 4-12 months

Question 17

risk factors for primary tb

Answer 17

age

immune function

Question 18

disseminated primary including cns tb most common in who

Answer 18

young and immunocompromised

Question 19

most common place for primary tb

Answer 19

lymph node or pleural disease

Question 20

when does reactivation tb occur

Answer 20

18-24 months after infections

Question 21

what is most common for reactivation tb

Answer 21

pneumonia - upper lobe pulmonary

extra pulmonary in immunocompromised

Question 22

high risk factors for active tb

Answer 22

silicosis 
HIV AIDS 
chronic renal disease 
head and neck carcinoma 
recent TB infection 
abnormal chest xray-fibronodular disease 
immunosuppresive therapy

Question 23

moderate risk factors for active tb

Answer 23

diabetes
glucocorticoids
TNFalpha
0-4 years old when infected

Question 24

diagnosis for active pulmonary tb

Answer 24

signs and symptoms
radiograph
microbiology testing

Question 25

clinical signs and symptoms

Answer 25

dry then productive cough >2weeks fever, night sweats anorexia, weight loss hemoptysis, chest pain

Question 26

microbial testing for active disease

Answer 26

acid fast bacilli smear stain - rapid inexpensive mycobaterial culture/susceptibility - gold standard, 2-8wks molecular diagnositics - pcr and susceptibility

Question 27

radiograph for active disease

Answer 27

apical and upper lobe patchy infiltrates | volume loss and cavitation

Question 28

goals of treatment for active tb

Answer 28

eradicate the bug to cure the disease, prevent complications, and reduce mortality prevent AM resistance prevent transmission

Question 29

how often do you follow up sputum samples

Answer 29

monthly until to consecutive negatives

Question 30

how long is someone with active tb in isolation

Answer 30

initial 2 weeks and until 3 consecutive negative results

Question 31

principles of active tb AM

Answer 31

combo therapy adherance important both to optimize killing and decrease resistance

Question 32

standard regimen 1 for active tb

Answer 32

isonazid, rif, ethambutol, pyranzinimide for 2 months | then inh and rif for 4 months

Question 33

regimen 2 for active tb

Answer 33

inh, rif, emb for 2 months | then inh and rif for 7 months

Question 34

what regimen should elderly use for active tb

Answer 34

regimen 2, higher hepatooxicity in the older people

Question 35

what regimen should pregnant women use for active tb

Answer 35

either one

Question 36

what is direct observed therapy

Answer 36

initial 2 months instead of daily 5x a week and then for the continuation 3x a week at higher doses

Question 37

why is ethambutol added

Answer 37

in case there is resistance to the other agents can discontinue once results come back that its senstive to the others

Question 38

risk factors for ressitance

Answer 38

high local resistance rates previous tb infection exposure to resistant tb

Question 39

isonazid dose

Answer 39

5mg/kg max 300

Question 40

rifampin dose

Answer 40

10mg/kg max 600

Question 41

pyranzinamide dosing

Answer 41

20-25mg/kg

Question 42

ethambutol dosing

Answer 42

15-20mg/kg

Question 43

second line drugs for active tb

Answer 43

levofloxicin, moxi | ampikacin

Question 44

ampikacin dosing

Answer 44

15mg/kg injection

Question 45

which drugs have to be changed in hemodialysis

Answer 45

pyranzinimide 25- 35 3x a week | ethambutol 15-25 3x a week

Question 46

which are cidal

Answer 46

rif, inh, pyr

Question 47

which are static

Answer 47

emb

Question 48

which are extracellular

Answer 48

inh, rif

Question 49

which are intracellular

Answer 49

pyr, emb, rif

Question 50

inh adverse effects

Answer 50

hypersensitivity hepatotoxicity NV peripheral neuropathy

Question 51

what can you do to prevent peripheral neuropathy

Answer 51

give vit B6

Question 52

what drug should be avoided when on therapy

Answer 52

tylenol - affects liver

Question 53

what increases the incidence of hepatotoxicity

Answer 53

``` age >35 female pre existing liver disease other hepatotoxic drugs alcohol use ```

Question 54

when should you monitor for hepatotoxicity

Answer 54

baseline then in 2 weeks then monthly

Question 55

inh drug interactions

Answer 55

inhibits cyp 2C9 and 3A4 | antacids reduce absorption

Question 56

rifampin adverse effects

Answer 56

hypersensitivity hepatotoxicity orange discoloration of saliva urine and tears

Question 57

rifampin drug interactions

Answer 57

inducer of 3A4 and pgp | max in 7 days and returns to baseline in 14

Question 58

pyranzinamide adverse effects

Answer 58

hepatotoxicity hypersensitivity hyperuricemia - gout if preexisting, arthralgias

Question 59

ethambutol adverse effects

Answer 59

ocular neritis - eye exams indicated, dose dependent (high dose long time) CNS, peripheral neuritis hypersensitivity - rash, fever, dermatitis

Question 60

what to do if the patient gets a drug induced rash

Answer 60

stop all drugs and start second line agent review other potential causes once rash resolves start inh in 3 days start rif (can take off second line here) in 3 days start emb if no rash assume it was pyr if rash occurs with any step then discontinue and restart all the others, adjust regimen based on those continues

Question 61

what to do if patient experiences drug induced hepatotoxicity AST or ALT >5x ULN or clinical jaundice

Answer 61

discontiue all meds and start second line agent check for other causes , cehck viral hep serologies when levels normal start rif after 2 weeks start inh if normal transaminases after 2 weeks assume pyr and do not rechallenge if hepatitis occurs with any then discontinue and restart the others adjust treatment based on remaining