Emphysema - Pathology - ATOT

Topic: Emphysema
Subject: Pathology
Course: ATOT 2nd year

Emphysema: Definition, Types, Pathogenesis, Morphology, Clinical features and Complications of Emphysema

Meant for BSc ATOT students and other allied health sciences

Reference: Ramadas Nayak - Exam Preparatory Manual for Undergraduates - Pathology

1. Emphysema Dr. Salman Ansari Dept. of Pathology Kanachur Institute of Medical Sciences

2. Contents Definition Types of emphysema Pathogenesis Morphology Clinical features Complications

3. Emphysema Definition : Irreversible dilation of air spaces distal to terminal bronchiole, accompanied by destruction of their walls.

4. Types of emphysema Classified according to anatomic distribution. Centriacinar Panacinar Paraseptal Irregular

5. Centriacinar: - upper lobes - involve the central or proximal parts of the acini (formed by respiratory bronchioles), whereas distal alveoli are spared. - occurs predominantly in smokers, in association with chronic bronchitis. Panacinar : - acini uniformly enlarged - lower lobes of lung - α1 antitrypsin deficiency

6. 3. Distal/paraseptal acinar : Dilatation affects the distal airspace at the periphery of the lobule and the proximal portion is normal. Site : Adjacent to pleura, along the lobular connective tissue septa - Areas of fibrosis, scarring and atelectasis - Multiple,continuous,enlarged airspaces, less than 0.5cm to more than 2.0 cm Cyst like structures. Spontaneous pneumothorax.

7. 4. Irregular : - Acinus is irregularly involved - associated with scarring. - asymptomatic and clinically insignificant. - most common type

8. Pathogenesis Factors involved in pathogenesis of emphysema are: Inflammatory mediators released in lung Protease-antiprotease mechanism Imbalance of oxidants and antioxidants Oxidative stress Airway infection

9. Protease- antiprotease imbalance hypothesis : Injury due to heavy smoking and pollution causes activation of inflammatory cells like neutrophils This causes damage to epithelial cells - genetic deficiency of the antiprotease a1-antitrypsin: enhanced tendency to develop emphysema which is increased by smoking.

10. α1-Antitrypsin: present in serum, tissue fluids, and macrophages Major inhibitor of proteases (particularly elastase) secreted by neutrophils. Emphysema results from destructive effect of high protease activity in people with low antiprotease activity.

11. Morphology Gross: Voluminous lungs Upper two thirds of lung Large apical blebs or bullae Microscopically : Large alveoli separated by thin septa Destruction of septal wall fibrosis and chronic inflammation of the walls.

12. Clinical features Dyspnea , cough, wheezing Prolonged expiration Barrel chest Pink puffers

13. Complications (i) Cor pulmonale (ii) congestive heart failure due to secondary pulmonary hypertension and pneumothorax. (iii) death

14. Death is due to: Respiratory acidosis and coma Rt sided heart failure Massive collapse secondary to pneumothorax

15. References : Ramadas Nayak - Exam Prep Manual for Undergraduates Questions : [email protected] For PPT, scan: For notes, click here or scan: