Emphysema

patho

1. EMPHYSEMA Dr. Sujan Vaidya

2. OBJECTIVES Emphysema: definition types pathogenesis

3. EMPHYSEMA condition of the lung characterized by irreversible enlargement of the airspaces distal to the terminal bronchioles is accompanied by destruction of their walls without obvious fibrosis.

4. TYPES OF EMPHYSEMA centriacinar panacinar paraseptal irregular

5. TERMINAL PORTION OF RESPIRATORY TREE

6. TYPES OF EMPHYSEMA centriacinar: central or proximal part of acini, formed by respiratory bronchioles, are affected distal alveoli are spared seen in heavy smokers

7. TYPES OF EMPHYSEMA panacinar: acini uniformly enlarged from level of respiratory bronchiole to terminal blind alveoli. associated with deficiency of α 1 -antitrypsin

8. TYPES OF EMPHYSEMA paraseptal (distal acinar): distal part is predominantly involved. proximal portion of the acinus is normal

9. TYPES OF EMPHYSEMA irregular: acinus irregularly involved almost always associated with scarring most common form

10. PATHOGENESIS emphysema arises as a consequence of 2 critical imbalances: protease (elastase)- antiprotease imbalance oxidant-antioxidant imbalance effects of imbalances lead to tissue damage.

11. PROTEASE-ANTIPROTEASE IMBALANCE imbalance due to deficiency of α 1 -antitrypsin α 1 -antitrypsin: normally present in serum, tissue fluids & macrophages major inhibitor of proteases (elastase), secreted by neutrophils during inflammation.

12. patients with genetic deficiency of α 1 -antitrypsin have ↑↑ tendency to develop emphysema. this tendency is ↑ with smoking about 1% of all patients with emphysema have this defect

13. PROTEASE-ANTIPROTEASE IMBALANCE neutrophils (principal source of proteases) are normally present in peripheral capillaries (including lungs) few gain access to the alveolar spaces neutrophilic elastase capable of digesting human lung, but inhibited by α 1 -antitrypsin

14. PROTEASE-ANTIPROTEASE IMBALANCE sequence of events: in smokers, neutrophils and macrophages gain access to alveolar spaces any stimulus that ↑ no. of neutrophils and macrophages in the lung or the release of proteases→ ↑ proteolytic activity if serum α 1 -antitrypsin is ↓, elastic tissue destruction is unchecked → emphysema

15. PATHOGENESIS OF EMPHYSEMA

16. OXIDANT-ANTIOXIDANT IMBALANCE normally, antioxidants (Eg: glutathione) are present in the lungs tobacco smoke contains abundant free radicals smoking releases reactive oxygen species (free radicals ) which deplete anti-oxidants present → inactivate anti-proteases → tissue damage

17. CLINICAL FEATURES dyspnoea: begins insidiously and is progressive expiration prolonged cough 3. weight loss

18. THANK YOU