200 likes | 427 Views
Chronic Obstructive Pulmonary Disease. Shannon Barkley, MD MPH Swedish Family Medicine Residency April 12, 2011. Definition. Chronic progressive airflow limitation that is not fully reversible
E N D
Chronic Obstructive Pulmonary Disease Shannon Barkley, MD MPH Swedish Family Medicine Residency April 12, 2011
Definition • Chronic progressive airflow limitation that is not fully reversible • Chronic abnormal inflammatory response of lung to noxious particles or gases resulting in small airway disease (obstructive bronchiolitis) and parenchymal destruction (emphysema) • Variable pathological lung changes (parenchymaland small airway disease) • Extra-pulmonary effects and comorbities influence severity • Long term decline in function • Periodic exacerbation characterized by change in baseline dyspnea, cough, or sputum that exceeds day-to-day variation (caused by infection, cardiopulmonary disease)
Emphysema vs. Chronic Bronchitis Interesting clinically and has ramifications for complications but treated the same.
Epidemiology • 47% prevalence of COPD on spirometry screening in general practice patients who were currently smoking and had history of smoking ≥ 15-pack-years • number of deaths from COPD in United States • 121,267 in 2003 (64.3 per 100,000 population ≥ 25 years old) • 117,134 in 2004 (61.1 per 100,000 population ≥ 25 years old) • 126,005 in 2005 (64.3 per 100,000 population ≥ 25 years old) • Fourth leading cause of mortality world-wide • Overall global prevalence estimated 4-20% (varies with population studied)
Etiology • Pathogenesis • Inflammation-induced structural changes, including small airway remodeling and narrowing • Parenchymal destruction • Subsequent reduction in ability of airways to remain open during expiration • COPD progression associated with small airway changes with accumulation of inflammatory mucous exudate in lumen and inflammatory infiltrate (including lymphoid follicles) in wall
Risk Factors • Exposure to inhaled particles • smoking cigarettes, cigars, marijuana • occupational dusts/vapors • indoor air pollution, particularly from burning biomass fuels in confined spaces; passive smoke exposure) • Other risk factors • outdoor air pollution • history of repeated lower respiratory tract infections during childhood, • history of pulmonary tuberculosis • chronic asthma • intrauterine growth retardation • poor nutrition • use of topical beta-blockers • western diet • acetaminophen use • poor socioeconomic status • Alpha-1 antitrypsin deficiency
Complications • Disease Specific • Disease exacerbation • Respiratory failure • Hypoxia (noctural/exercise induced) • Pulmonary HTN, Bullous Emphysema • Infection (H. influenza, S. pneumoniae, P. aeruginosa,M. catarrhalis, S. aureus, Enterobacteriaceae, C. pneumoniae, Mycoplasmapneumoniae) • Systemic • Depression • Weight Loss (higher energy expenditure) • Skeletal muscle weakness/wasting • Normochromic/normocytic anemia or polycythemia • Cardiovascular Disease, corpulmonale • Disability • Osteoporosis (chronic steroids) • Bronchial carcinoma: 2.8 times greater risk for incident lung cancer (95% CI 1.8-4.4)
Diagnosis • Insufficient evidence to support use of specificHxand PE items for COPD diagnosis • History items with some diagnostic value • dyspnea • wheezing • previous consultation for wheezing or cough • self-reported COPD (positive likelihood ratio 8.3, negative likelihood ratio 0.8) • age ≥ 45 years old (positive likelihood ratio 2.8, negative likelihood ratio 0.8) • smoking (> 40 pack years of smoking, current smoking) (positive likelihood ratio 7.3, negative likelihood ratio 0.5) • Physical examination items with some diagnostic valu • wheezing • forced expiratory time • laryngeal height - Maximum laryngeal height 4 cm or less (from top of thyroid cartilage to suprasternal notch) (positive likelihood ratio 1.3, negative likelihood ratio 0.4) • prolonged expiration • Presence or absence of ALL 4 with LR could rule in (positive likelihood ratio 220.5) or rule out (negative likelihood ratio 0.13) chronic OAD
Pulmonary Function Testing • Why get PFTs? • Identify disease • Follow disease course • Quantify disease severity • Assess response to treatment (bronchodilators) • Exclude other diseases from differential (i.e. extrinsic obstruction) • Pre-operative evaluation
Interpreting PFTs • Lung Volumes • Flow Rates • Bronchodilator response • Methacholine challenge • Inspiratory and Expiratory Pressures • Diffusion Capacity (DLCO)
Flow-Volume Loops Peripheral Obstructive Central Obstructive Normal Combined Obstructive-Restrictive Restrictive
Case 1 • Case 3 • Case 4 • Case 7 Case Studies PFT Interpretation
Chronic Treatment • C – Corticosteroids (inhaled) • 20% decrease in exacerbations if FEV1 < 2.0 L • Increase in pneumonia no change in mortality (with inhaled steroids alone) • O – Oxygen • If PaO2 ≤ 55 mm Hg or SaO2 ≤ 89% to prevent corpulmonale/decrease mortality • P – Prevention • Smoking Cessation – 50% reduction in lung function decline, decreased mortality • Flu/Pneumovax • D – Dilators • Anticholinergics > B2 agonist, combo may be more effective • Tiotripium superior to ipratropium and superior to LA B2 agonist • LABA + inhaled corticosteroid my decrease mortality • E – Experimental • Lung volume reduction surgery – increase exercise capacity, decreased mortality if FEV1 > 20%, upper lobe emphysema • Roflumilast (PDE III inhibitor): Increases FEV1 • R – Rehabilitation/Exercise • Including exercise, nutrition counseling, and education may improve dyspnea, fatigue, walking distance and quality of life
Treatment of Exacerbation • A word about B-Blockers: • Cardioselective B-blockers not associated with adverse respiratory effects in patients with COPD • B-blockers associated with reduced risk of mortality and COPD exacerbation • Topical B-Blockers leading to increased hospital stays?
Case 1 • Case 2 • Case 5 • Case 6 Case Studies Arterial Blood Gases
Prognosis • Progressive Disease • LOTS of comorbidities • FEV1 • < 50% predicted 5y mortality 10% • < 40% predicted 5y mortality 50% • < 20% predicted 5y mortality 90% • BODE (10 pt scale, HR 1.62 for resp mort for each 1 pt increase) • BMI: ≤21 (+1) • Obstruction (FEV1): 50-64% (+1), 36-49 (+2), ≤ 35 (+3) • Dyspnea: walking level (+1), after 100 yards (+2), with ADL (+3) • Exercise Capacity 6 min: 250-349 m (+1), 150-249 m (+2), ≤149 m (+3) • ADO Index • Age, Dyspnea, Obstruction • Continued Smoking/Frequent Exacerbations
Prevention • Smoking cessation - single most effective (and cost effective) intervention to reduce risk of developing disease • Reduce exposure to • tobacco smoke • occupational dusts • occupational chemicals • indoor and outdoor air pollutants