Tuberculosis (Case Based) + Pretty Based if u ask me Flashcards
Discuss the difference between Smear Test Positive and Smear Test Negative TB.
Smear Test Positive TB denotes an active TB with a high bacterial load, such that it may be picked up by the Smear Test. Smear Test negative TB could still be active TB, but with a lower bacterial load.
Smear Test Positive TB is known to be generally more infectious than smear test negative TB.
A patient tests positive for Mycobacteria PCR, but negative for smear test, and does not respond to first-line TB antibiotics. What could be the root cause?
Non-Tuberculosis Mycobacteria
Patient presents with Tuberculosis-like symptoms. However, patient desaturates quickly and serology test reveals wrinkled colonies. What do you suspect?
Meliodosis (Burkholderia pseudomallei)
What does TST stand for?
Tuberculin Skin Test (TST)
What does IGRA stand for?
Interferon Gamma Release Assay (IGRA)
What does BCG stand for?
Bacillus Calmette–Guérin vaccine
Discuss some true and false statements regarding Tuberculin Skin Test (TST) and Interferon Gamma Release Assay (IGRA).
a. TST has more expensive reagents than IGRAs.
b. TST is a more time critical process than IGRAs.
c. TST involves a return visit by the patient, IGRA does not.
d. TST has more false positives than IGRA.
e. A reactive TST or IGRA result means that the patient has active TB
f. A reactive TST or IGRA means that the patient has been infected with TB in some point in their lives.
a. F (TST is cheap)
b. F (Both are time critical)
c. T
d. T (BCG Vaccine has similar antigens, since it is also from a a purified protein Derivative)
e. F
f. T
Compare the sensitivity of the AFB smear, TB PCR and TB culture.
TB culture > TB PCR»_space;> AFB smear.
AFB smear has a sensitivity of 30%.
TB PCR has a sensitivity of 75-80%
TB culture has a sensitivity of 90%
Compare the specificity of the AFB smear, TB PCR and TB culture.
TB culture ~= TB PCR > AFB smear
AFB smear has a specificity of 90%.
TB PCR and culture have a specificity of 99%.
