Unit 3- TB Flashcards
(30 cards)
Factors that increase risk of TB include:
Foreign-born minorities
lower socioeconomic status and crowded housing
HIV
Multi-drug resistance
weak immunity
child <5
T or F: TB spreads by airborne
FALSE
Spreads by droplet
When TB is in miliary
bacilli spread to all parts of bod, rare but FATAL if UNTX
When TB in CNS
occurs as meningitis
When TB occurs outside the lungs
usually NOT INFECTIOUS, unless concomitant pulm disease, extrapulmonary disease of oral cavity or larynx, or with open site
MDR (multi drug resistant) TB:
caused by bacteria resistant to best TB drugs isoniazid and rifampin
XDR (extensively drug resistant) TB
caused by organisms resistant to isoniazid and rifampin, plus fluoroquinolones and >=1 of the 3 injectable second-line drugs
Latent TB infection
granulomas may persist
2-8 weeks after infection: LTBI can be detected via TST or interferon-gamma release assay
Immune system is usually able to stop the multiplication of bacilli
TB disease
granulmonas break down>bacilli escape>multiple>TB disease
can occur soon after infection or years later
Positive M. tb cultures confirms dx
Can a person with LTBI spread the TB bacteria to others
NO
small amount of TB bacteria in the body that are alive but inactive
Does NOT feel sick but may become sick
Which of the following is true in a person with LTBI:
a. CXR is normal
b. Sputum smear and cultures are negative
c. Should be tx with 4 different medications
d. Does not require isolation
e. Is considered a TB case
a, b, d
should consider tx to prevent TB disease
Methods for detecting TB
Mantoux tuberculin skin test (TST)
IGAs: quantiferon-TB gold in-tube
T-spot TB
These tests DOONT exclude LTBI or TB disease
Mantoux tuberculin skin test (TST)
purified protein derivative (PPD)
Takes 2-8 weeks after exposure and infection for immune system react to PPD
Reading in 48-72 hours
PPD
0.1mL to produce 6-10m diameter
read 48-72 hr after
> =5 positive in: HIV, recent contact of TB, persons with fibrotic changes on CXR, organ transplant
> =10: travels to high prevalence, injection drug users, high-risk congregate setting, mycobacteriology lab personnel, persons w/ increase risk for progressing, child <5
> =15: person with no known risk factors for TB
Interferon gamma release assay (IGRAs) work by
detecting infection by measuring immune response in blood
CANNOT detect between TB and LTBI
CAN be used as surveillance/screening
IGRAs should not be used in children less than?
5
unless used in conjunction with TST
Sx of pulm TB
prolonged cough (3weeks) hemoptysis chest pain loss or apetite unexplained weight loss night sweats fever fatigue
Sx of possible extrapulm TB
Hematuria (TB of kidney) H/A Confusion (meningits) Back pain (TB spine) Hoarseness (TB larynx) Loss of appetite unexplained weight loss night sweats fever fatigue
T or F: CXR can confirm TB
FALSE
posterior/anterior view is standard
HIV pt may have typical appearance
What is used for bacteriologic exam of speciments
AFB smear
NAA testing
Culture and identification
Drug-susceptibility
*sputum culture
collect at least 3, at 8-24 hour intervals, at least 1 in the morning
Smear examination of specimen
quickest and easiest procedure
provides preliminary dx
Direct detection using nucleic acid amplificaion (NAA)
test rapid via DNA and RNA
Earlier lab confirmation, earlier resp isolation and tx, improved pt outcomes
Perform at least 1 on each suspect
single negative does not exclude TB
What is the gold standard for confirming dx
CULTURE
results 4-14 days
Who is a candidate for LTBI?
a. high-risk with + IGRA or TST of >5
b. High-risk with +IGRA or TST >10
c. persons with conditions that inrease risk
d. low-risk persons with + IGRA and TST >15
e. all of the above
E. All of the above
