tuberculosis

Question 1

tuberculosis

Answer 1

The lungs are the major site for Mycobacterium tuberculosis primary infection and disease.

transmitted via droplets

Primary tuberculosis is a term that describes new tuberculosis infection or active disease in a previously naïve host

After primary infection, 90 percent of individuals with intact immunity control further replication of the bacilli, which may then enter a “latent” phase.

reactivation of a previous focus of mycobacterial containment that was seeded at the time of the primary infection

testing:
tuberculin skin test

subdermal injection
measure size of enduration

false positive in those who have recieved the BCG vaccine
false negatives in those who are immune suppressed

Interferon gamma release assay

blood test
more specific. similar sensitivity

chest x ray
acid fast bacilli staining

Question 2

Tuberculosis treatment

Answer 2

Isoniazid
rifampacin
pyrazinamide
ethambutol

pyridoxine is given to try and prevent isoniazid side effects

Question 3

Isoniazid

Answer 3

Isoniazid is a prodrug and must be activated by a bacterial catalase-peroxidase enzyme in Mycobacterium tuberculosis called KatG.This process inhibits the synthesis of mycolic acids, which are required components of the mycobacterial cell wall.

Up to 20% of people taking isoniazid experience peripheral neuropathy

Question 4

Rifampacin

Answer 4

Rifampicin inhibits bacterial DNA-dependent RNA synthesis by inhibiting bacterial DNA-dependent RNA polymerase.

The most serious adverse effect is hepatotoxicity

Question 5

Pyrazinamide

Answer 5

Pyrazinamide is a prodrug that stops the growth of Mycobacterium tuberculosis

Question 6

ethambutol

Answer 6

Ethambutol is bacteriostatic against actively growing TB bacilli. It works by obstructing the formation of cell wall.