2016 PTB Flashcards
Previously treated for TB, declared cured and is now diagnosed with TB
Relapse
Previously treated for TB and declared treatment failure at the end of most recent course of treatment
Treatment after failure
True or False: serum Uric acid should be taken before starting TB treatment
False. Serum Uric acid is not recommended before starting anti TB treatment. Asymptomatic hyperuricemia is not indication to hold pyrazinamide
What is the effective treatment regimen for new PTB cases?
2HRZE and 4HR (isoniazid + rifapicim)
Target: cell wall. Inhibits mycolic acid
Isonizid
Target: nucliec acid. Inhibits transcription by interfering the DNA dependent RNA polymerase
Rifampicin
Mechanism of resistance. Rifampicin
Mutation in rpoB gene
Target: intracellular. Targets essential membrane transport, in fatty acid synthesis
Pyrazinamide
Drug dose per Kg body weight HRZES.
H 5 R 10 Z 25 E 15 S 15
Mechanism of resistance. Streptomycim
Mutation of ribosome target binding sites
Target: ribosome. Inhibits translation during protein synthesis
Streptomycin
Target: cell wall. Affects Lipid and cell wall metabolism. Inhibits RNA synthesis.
Ethambutol
Mechanism of resistance. Ethambutol
Mutation of embCAB gene
Mechanism of resistance. Pyrazinamide
Mutation in pncA gene
Gold standard of PTB diagnosis
TB culture
LED vs Zeihl Neelsen microscopy
LED is preferred. More sensitive and more specific
Indications for Drug sensitivity testing
ALL cases of re treatment, treatment failure, MDR suspects; Also for known contacts of MDR-TB, PLHIV
Additional work up for smear negative patients
CXR for all smear negative presumptive PTB. If available, Xpert MTB/Rif should be requested for CXR positive presumptive PTB
Pre-treatment tests prior to initiating TB treatment
SGPT, Creatinine, FBS