demographics

• Australia has one of the lowest rates of tuberculosis (TB) in the world with an annual incidence of 5·2–7·0 per 100,000 population
• ATSI 5-6x
• People who were born and grew up in Australia are very unlikely to get TB, unless they have close contact with a sick person

Aetiopathology

• Is a bacterial disease caused by Mycobacterium tuberculosis, mainly affecting the lungs
• Primary infection is transmitted by airborne droplets, is often initially asymptomatic as the bacteria lays dormant as the hosts immune system is able to keep it in check (known as latent tuberculosis). If the immune system becomes compromised, reactivation of the disease may occur
  • Primary TB
    • Causes activation of macrophages and formation of granulomas (1-2 cm caseating granulomas in lung (Ghon focus) with involvement of lymph nodes (Ghon Complex)
    • Stimulation of cell mediated immunity ;leads to healing with fibrosis and calcification (majority) or in a few spread (progressive pr.)
  • Secondary TB
    • Secondary entry of bacteria in immunocompromised adult
    • Typical cavity pulm. TB and many other organ TB

Risk Factors

• History of previous TB infection or disease state
• Known or possible TB exposure
• Past / present residence in or travel to an endemic TB area
• Overcrowding
• Low socioeconomic status
• Minority groups
• Alcohol
• IV drug use