Introduction emphysema A condition characterized bydilation of air spaces (with ↓ elasticity and ↑ compliance) due to alveolar wall destruction normally, elastin in the wall functions to keep alveoli open capillaries are destroyed along with the alveoli Causes smoking most common cause α1-antitrypsin (AAT) deficiency AD disorder (codominant) MM phenotype is normal ZZ phenotype results in disease AAT normally inhibits the action of elastase without AAT elastase is unchecked and destroys the elastic tissue of the alveoli as a result emphysema develops at early age may also develop cirrhosis due to the inability to release an abnormal form of AAT from the liver resulting in hepatotoxicity Classification Centriacinar dilated respiratory bronchiole most common presentation of emphysema due to smoking result of inhaled tobacco toxins arriving first in the respiratory bronchioles before traveling to the alveolus most commonly in the upper lobes result of upper lobes receiving exposure to smoke Panacinar dilated alveoli most common presentation of AAT deficiency also due to a functional AAT deficiency as a result of smoking oxidants and inflammatory reaction of smoke can destroy AAT smoking exacerbates effects of genetic AAT deficiency most commonly in the lower lobes result of lower lobes recieving ↑ perfusion allowing more immune cells to traffic into the alveoli Paraseptal most commonly involves young, otherwise healthy males does not obstruct the airway associated with bullae found near the pleura increased risk for spontaneous pneumothorax Presentation Symptoms dyspnea classic pursed-lip breathing results in increased airway pressure and prevents airway collapse during exhalation Physical exam decreased breath sounds on auscultation increased anterior-posterior diameter (barrel chest) hyperresonant to percussion "pink puffer" (end-stage) Imaging Chest radiograph increased AP diameter with flattened diaphragms hyperinflated lungs loss of lung markings elongated heart Evaluation Labs ABG during exacerbation shows hypoxemia and acute respiratory acidosis AAT shows no α-globin peak on electrophoresis Pulmonary function tests decreased FEV1 sec / FVC increased TLC and RV decreased diffusion capacity from destruction of capillaries Treatment Conservative smoking cessation ambulatory O2 Pharmacologic bronchodilators for symptom improvement inhaled steroids reduce exacerbations oral/IV steroids and antibiotics for acute exacerbations