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KEY CONCEPTS
Chronic obstructive pulmonary disease (COPD) is a treatable and preventable disease characterized by progressive airflow limitation that is not fully reversible and is associated with an abnormal inflammatory response of the lungs to noxious particles or gases.
Mortality from COPD has increased steadily over the past three decades; it is the fourth leading cause of death in the United States.
The primary cause of COPD is cigarette smoking, implicated in 75% of diagnosed cases in the United States. Other risks include genetic predisposition, environmental exposures (including occupational dust and chemicals), and air pollution.
In patients with COPD, staging of airflow limitation (GOLD 1-4) is classified by spirometry measurements. Disease severity (Category A-D) is classified using a combined assessment of symptom score, as measured by a validated questionnaire, and risk for future exacerbations.
Smoking cessation and avoidance of other known toxins are the only management strategies proven to slow COPD progression.
Oxygen therapy can reduce mortality in selected patients with COPD. Oxygen therapy is indicated for patients with a resting PaO2 of less than 55 mm Hg (7.3 kPa) or a PaO2 of less than 60 mm Hg (8.0 kPa) and evidence of right-sided heart failure, polycythemia, or impaired neurologic function.
Inhaled bronchodilators are the mainstay of drug therapy for COPD and are used to relieve patient symptoms and improve exercise tolerance and quality of life. Guidelines recommend short-acting bronchodilators as initial therapy for patients with occasional symptoms and all patients as rescue therapy to relieve symptoms.
For patients experiencing persistent symptoms, either a long-acting β2-agonist (LABA) or long-acting anticholinergic (LAMA) offers significant benefits, and both are of comparable efficacy. If a patient has continued symptoms, combining long-acting bronchodilator agents (LABA plus LAMA) is recommended.
For patients at high risk for future exacerbations, either a long-acting β2-agonist (LABA) or long-acting anticholinergic (LAMA) is effective at reducing exacerbation frequency. Anticholinergic agents are more effective at reducing exacerbation frequency and should be considered first-line. If a patient has continued exacerbations or has more severe disease, combining long-acting bronchodilator agents (LABA plus LAMA) is recommended.
The role of inhaled corticosteroid (ICS) therapy in COPD is controversial. Patients with frequent and severe exacerbations may benefit from ICS therapy, although the risk of pneumonia is increased.
Acute exacerbations of COPD (AECOPD) have a significant impact on disease progression and mortality. Treatment of acute exacerbations includes intensification of bronchodilator therapy and a short course of systemic corticosteroids.
Antimicrobial therapy should generally be used during AECOPD if the patient exhibits at least two of the following: increased dyspnea, increased sputum volume, and increased sputum purulence. A C-reactive protein (CRP) test may be helpful to guide the decision to treat a COPD exacerbation with antibiotics.
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BEYOND THE BOOK
Watch the video entitled “Pathophysiology of Large and Small Airway Disease in COPD” in AccessPharmacy by Scott Stern, MD. This 5-minute video ...