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Emphysema. 1. What is Emphysema?. Specifically, two things combined:. Permanent abnormal enlargement of the acini ( acinius , Latin for “berry”) (MedicineNet, 1999) Destruction of alveolar walls without obvious fibrosis (McCance & Huether, 2006).
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What is Emphysema? Specifically, two things combined: • Permanent abnormal enlargement of the acini (acinius, Latin for “berry”) (MedicineNet, 1999) • Destruction of alveolar walls without obvious fibrosis (McCance & Huether, 2006) (as opposed to something like Asbestosis: http://en.wikipedia.org/wiki/Asbestosis) Image from www.nucleusinc.com 2
Two kinds of emphysema Primary emphysema • 1-2% of cases • Inherited lack of alpha-1 antitrypsin, a protective protein (inhibits neutrophil elastase) Secondary emphysema • Also caused by inability to inhibit proteolytic enzymes in the lungs • From inhaled toxins (e.g., cigarette smoke) • 20% of smokers at risk (McCance & Huether, 2006) 3
Secondary Emphysema: Pathophysiology • Toxins (smoke) cause inflammation • Infiltration of neutrophils, macrophages and lymphocytes • Inflammatory cytokines increase protease activity, inhibiting normal antiprotease activity (antitrypsin) • Alveoli are destroyed because elastin is being broken down by proteases (McCance & Huether, 2006) 4
Emphysema & Normal Alveoli • Loss of septa • Loss of capillary beds • Hyperinflation • Loss of elastic recoil & collapse of alveoli • Increased residual volume • Decreased diffusion • (lower SA/Volume ) 6
Bullous Emphesyma “Bullae are large dilated airspaces that bulge out from beneath the pleura.” [Image and quote from http://medlib.med.utah.edu/WebPath/LUNGHTML/LUNG056.html] 7
Centriacinar (centrilobar) Emphysema Respiratory bronchioles in proximal portion of acinus are lost Alveoli distal to terminal bronchiole intact Occurs in smokers with chronic bronchitis Usually in upper lobes 8
Emphysema: Clinical Manifestations • Dyspnea • Wheezing is minimal • Barrel chest, often thin • Tachpynea with prolonged expiration • Pursed lip breathing • Tripod stance • Hypoxemia &/or hypercapnia • Chronic hypoventilation (later stage) • Not much coughing with little sputum (Productive cough with infection) 9
Radiograph: Emphysema, Pulmonary hypertension, Cardiomegaly • Flattened diaphragm • Hyperinflation • Translucency of lung • Hypertrophy of heart • (Hypoxia/ hypercapnea & damage = pulmonary vasoconstriction & hypertension. • Later cor pulmonale) 12
Clubbing of the Nails A sign of chronic hypoxia 13
Normal Spirograph FEV1/VC normally greater than 75% (per Walters presentation) Emphysema Spirograph Decreased FEV1/VC Total Lung Capacity normal or increased RV increased 14