Tuberculosis Flashcards
What is Tuberculosis?
An aerobic, non spore forming AFB. It is non motile and slow growing.
What is the reservoir of TB?
Humans although rarely, elephants can contract the infection
What are the barriers to acquiring an infection with TB?
Public Health Structure
Air Exchange
Alveolar Macrophages
CD4 and CD 8 Lymphocytes
How is a TB infection acquired?
Aerosolized droplets from coughing and sneezing.
What is the pathophysiology of TB infection?
AFB inhaled. Upon arrival in alveolus, they enter the alveolar macrophage and is encased in phagosome. The phagosomes fuse with lysosomes which digest them. CD4 and CD8 lymphocytes attack the AFB. The AFB is surrounded by a granuloma- the Ghon Complex.
What organ systems are affected by TB?
Pulmonary
Lymph Nodes
Pleura
CNS
What findings are associated with TB?
Non Specific X Ray findings at 10 days
Granuloma at 4 weeks
Positive skin test at 5 weeks
Visible chest x ray changes at 6 weeks
What are the two types of TB?
Latent (LTBI) Isocitrate Lyase\
Active
What are the first line drugs to treat TB?
INH, Rifampin, Pyrazinamide, Ethambutol, Rifabutin, Rifapentine
What are the second line drugs?
Streptomycin, Cycloserine, PAS, Amikacin/Kanamycin, Capreomycin, Levofloxicin, Moxifloxicin,Gatifloxicin
What are mechanisms of action of the first line drugs?
INH- disrupts cell membrane by interfering with Mycotic Acid Synthesis
Rifampin acts on Bacterial RNA Polymerasealtering Protein
Pyrazinamide- requires intra-bacterial activation in an acidic environment. It alter membrane efflux.. Works on M TB only
Ethambutol- Disrupts cell wall. does not require activation.
What is MDR TB?
TB resistant to INH and Rifampin. Seen especially in India, China and Russia.
What is XDR TB?
TB resistant to INH, Rifampin, Flouroquinolones and Aminoglycosides.
What is DOTS therapy?
Directly
Observed
Treatment
Short Course
What are some facts about Scrofula?
Painless
Usually in HIV pts.
Skin test + 77-100% 0f the time
6 month treatment
What are some facts about Pleural TB?
Sputum helps less than 40% of the time
Aspirate is usually serosanguineous with elevated Lactate levels and low Glucose levels