EMPHYSEMA

1. Tanya Holubiak MD4 # 1075 EMPHYSEMA

2. “Emphysema is a condition of the lung characterized by abnormal permanent enlargement of the airspaces distal to the terminal bronchiole, accompanied by destruction of their walls and without obvious fibrosis” † Definition

3. What is Emphysema? • General Considerations: • COPD • Permanent enlargement & destruction of airspaces • Loss of lung elasticity

4. 4 Major Types • CENTRILOBULAR (centriacinar) • PANACINAR • PARASEPTAL • IRREGULAR • Other Types • Compensatory Hyperinflation • Obstructive Overinflation • Bullous Emphysema • Interstitial Emphysema

5. 4 Major Types CENTRILOBULAR PANACINAR Enlargement is uniform from the respiratory bronchioles to the alveoli Tends to occur in the lower lung field & anterior margins, most severe form at the bases of the lung Cause is associated with Alpha 1-Antitrypsin deficiency Grossly increased size of the alveolar space & monotonous appearance ‡ • Enlargement of the centrilobular airspaces • Damage affects mainly the proximal & central respiratory bronchioles • Distal Alveoli spared • Commonly distributed in the upper lobe • Development believed to be correlated cigarette smoking, dust inhalation, & residents of smog filled cities‡ • Characteristic gross appearance is anthracosis in a patchy fashion

6. 4 Major Types (cont’d) PARASEPTAL IRREGULAR Acinus is irregularly involved Almost always is associated with scarring • Enlargement of the airspaces at the distal acinar • Lesions mostly along the dorsal surface of the upper lung† • Occurs along scarring & atelectasis • Often associated with fibrosis & may coexist w/ other emphysema • Responsible for spontatneous pneumothorax in young males

7. PATHOPHYSIOLOGY Major Physiologic Changes in the Lungs³ Physiologic Effects vary & depend on the severity of disease³ Relative degree of Bronchiolar obstruction vs. Lung Parenchymal destruction Irregularities include: Increases in Airway Resistance Decreases in Diffusing Capacity Massively Abnormal Ventilation-Perfusion ratios Pulmonary Hypertension • Chronic Infection from inhalation of smoke or other irritants that aggravate bronchi & bronchioles • Chronic Obstruction of many smaller airways • Entrapment of Air in the Aveoli & overstretching them

8. PATHOGENESIS Protease-Antiprotease Theory • Hypothesis to explain the damage of alveolar wall • Imbalances of protease-antiprotease & oxidant-antioxidant have additive effect on tissue damage • Excessive Protease + Less Anti-protease • Cigarette smoking • Contains Oxidants • Cause PMNs to release free oxy radicals • Inhibit α1-AT •  Neutrophil elastase release • Particles @ bifurcation of respiratory bronchioles • Engulfed by macrophages • release elastase & metalloproteinases • Released elastase can digest α1AT • Cause lung tissue damage

9. CLINICAL FINDINGS • Dyspnea • Weight Loss • Variable Coughing & Expectoration • Wheezing • Barrel-chested • Prolonged Expiration • Hunched-over sitting position • Breathing through pursed lips • Severe Emphysema • Cough is slight • Severe Overdistention • Diffusion Capacity is low • Blood gas fairly normal @ rest • “Pink Puffers” • Overventilation • Well oxygenated

10. CLINICAL FINDINGS (cont’d) • Death in most COPD patients from: • Respiratory Acidosis & Coma • Right-sided Heart Failure • Massive Collapse of the Lungs

11. DIAGNOSIS • Spirometry • High Resolution Computed Tomography (HRCT)

12. HRCT Normal Lung Moderate Centrilobular Panacinar HRCT of the normal lung. The pulmonary artery supplies 2 secondary lobules, and arrows indicate branching on the intralobular airways On HRCT, a “wall” structure is observed at the periphery of the emphysema, composed of compressed lung tissue and perilobularvessels. On HRCT, diffuse low attenuation changes are aboservedthrought out the lung field.

13. MANAGEMENT/TREATMENT Usual Options for Tx: In Selected Patients Lung Volume Reduction Surgery Lung Transplantation • Bronchodilators • Steroids • Bullectomy

14. CASE STUDY⁴ 57 year-old-man with severe, disabling end-stage emphysema was randomly assigned to a surgery group. Before surgery, the patient was able to walk only 100 to 200 yd (91-183 m) on level ground because of dyspnea & not able to perform the activities of daily living. Preoperative axial CT showed severe, heterogenous emphysema that predominantly affected the upper lobes. Color-enhance, 3D, volume-rendered imaging was used. This method showed, in this case, a marked predilection of the emphysema for the upper lobes.

15. CASE STUDY cont’d • Patient underwent bilateral video-assisted thoracoscopic surgery, with resection of the majority of the right upper lobe. • 1 year post-op: Patient was able to was a little more than 1 mile (1.6 km)

16. REFERENCES † Abbas, Abdul K. et. al. Robbins and Cotran: Pathologic Basis of Disease 7th Edition. Philadelphia, PA: Elsevier Inc., 2005. ‡ Takahashi, Masashi et. al. “Imaging of pulmonary emphysema: A pictorial review.” 2008. International Journal of COPD. Ed. Dove Press Vol. 3(2). 193-204. ³ Guyton, Arthur C. and Hall, John E. Textbook of Medical Physiology 11th Edition. Philadephia, PA : Elsevier Inc., 2006. ⁴Hunsaker, Andetta R. and Reilly, John J. “Centrilobular Emphysema with Predominantly Upper-Lobe Involvement.” 2003 New England Journal of Medicine. Massachusetts Medical Society. Vol. 348. 2091