1. Pulmonary tubercolosis Dr Nawal N Binhasher Assistant professor, Medical consultant, Medical department

2. Epidemiology The incidence of TB has been slowly rising since the 1980s of the previous century esp in eastern & southern Africa where HIV is common. The incidence of TB has been slowly rising since the 1980s of the previous century esp in eastern & southern Africa where HIV is common. By the beginning of this century, there were an estimated 8-9 million new cases & 1.8 million people died of TB in 2000. By the beginning of this century, there were an estimated 8-9 million new cases & 1.8 million people died of TB in 2000. With the present trend, 9-10 million new cases of TB are expected in 1020. With the present trend, 9-10 million new cases of TB are expected in 1020.

3. Epidemiology Across regions, sub-Saharan Africa has by far the highest annual incidence rate ≈ 290/100,000 population, but Asia harbors the largest No of cases. Across regions, sub-Saharan Africa has by far the highest annual incidence rate ≈ 290/100,000 population, but Asia harbors the largest No of cases. India, China, Indonesia, Bangladesh, & Pakistan together account for over half the global burden. India, China, Indonesia, Bangladesh, & Pakistan together account for over half the global burden. The most striking rises have been seen in sub- Saharan Africa & the former Soviet Union. These rises offset the fall in cases No in other parts of the world mainly west & central Europe, the Americas, & the Middle East. The most striking rises have been seen in sub- Saharan Africa & the former Soviet Union. These rises offset the fall in cases No in other parts of the world mainly west & central Europe, the Americas, & the Middle East.

4. Epidemiology Globally, ≈ 11% of TB cases are co- infected with HIV, 38% of that in sub-Saharan Africa & < 1% in china & India. Globally, ≈ 11% of TB cases are co- infected with HIV, 38% of that in sub-Saharan Africa & < 1% in china & India. Risk Factors: Risk Factors: 1. Geography (place & date of birth): as mentioned above 2. Immunocompromise: mainly HIV/AIDS (& others like: steroids, TNF –inhibitors, drug injection abusers) 3. Medical factors, like: DM; 8 folds higher, Cancer; esp hematological & head & neck ca,

5. Risk Factors Celiac disease, ESRD, intestinal bypass or gastrectomy, chronic malabsorption syndromes, Cigarette smoking, Iron status: ↑ dietary Fe is associated with an ↑ risk of pulmonary TB, Vitamin-D: an inverse relationship between vit-D levels & both active & latent TB infection has been shown in several studies. Celiac disease, ESRD, intestinal bypass or gastrectomy, chronic malabsorption syndromes, Cigarette smoking, Iron status: ↑ dietary Fe is associated with an ↑ risk of pulmonary TB, Vitamin-D: an inverse relationship between vit-D levels & both active & latent TB infection has been shown in several studies. Low socioeconomic status (poverty). Low socioeconomic status (poverty). Children & aging. Children & aging.

6. Pathophysiology The disease is spread by airborne droplets, containing MTB, inhaled & lodged in the distal AW. The disease is spread by airborne droplets, containing MTB, inhaled & lodged in the distal AW. MTB is taken up by alveolar macrophages in which it replicates with spread via the lymphatics to hilar LN & a few escape to blood stream. These cells interact with T lymphocytes with the development of cellular immunity that can be demonstrated 3-8 wks after initial infect’n by a + ve skin reaction to ID injection of protein from tubercle bacilli (tuberculin). MTB is taken up by alveolar macrophages in which it replicates with spread via the lymphatics to hilar LN & a few escape to blood stream. These cells interact with T lymphocytes with the development of cellular immunity that can be demonstrated 3-8 wks after initial infect’n by a + ve skin reaction to ID injection of protein from tubercle bacilli (tuberculin).

7. Pathophysiology The cell-mediated immunity leads to granuloma formation (central caseation »» may completely heal » many become calcified » 20% of these contain dormant tubercle bacilli » reactivation when host cellular immunity is depressed) The cell-mediated immunity leads to granuloma formation (central caseation »» may completely heal » many become calcified » 20% of these contain dormant tubercle bacilli » reactivation when host cellular immunity is depressed)