Chronic Obstructive Pulmonary Disease (COPD) Exacerbation 

Introduction - The Global Initiative for Chronic Obstructive Lung Disease (GOLD), a report produced by the National Heart, Lung, and Blood Institute and the World Health Organization defines a Chronic Obstructive Pulmonary Disease Exacerbation as an acute increase in symptoms beyond normal day-to-day variation [1]. This generally includes an acute increase in one or more of the following cardinal symptoms...

• Cough increases in frequency and severity
• Sputum increases in volume or changes in character
• Dyspnea increases from baseline (using inhalers/breathing treatments more often, increase in O2 use at home)

Etiology - Most precipitants of COPD exacerbations are secondary to viral and bacterial respiratory infections (estimated as 70-80% of the time). The other 20% is secondary to environmental pollution or unknown etiology. 

Risk of Exacerbations - The GOLD guidelines suggest using a combination of an individual’s FEV1 and history of exacerbations to assess the exacerbation risk. The severity of lung function impairment is stratified based on the postbronchodilator FEV1, using the GOLD classification of airflow limitation (see table below). These components are combined into the following risk stratification...

• Low risk: Typically GOLD 1 or 2 (mild to moderate airflow limitation) and/or 0 to 1 exacerbation per year. 
• High risk: Typically GOLD 3 or 4 (severe or very severe airflow limitation) and/or ≥2 exacerbations per year

Initial Evaluation - Initial evaluation of a patient with a suspected exacerbation of COPD includes a medical history, physical examination, chest xray, sputum culture and routine laboratory studies. Arterial blood gas analysis should be performed in most patients to assess the severity of the exacerbation and to establish a baseline from which improvement or deterioration can be measured. Patients with COPD who present to the hospital with acute worsening of dyspnea should be evaluated for potential alternative diagnoses, such as heart failure, pulmonary thromboembolism, and pneumonia.

Treatment - Supplemental oxygen is a critical component of acute therapy. It should target an O2 saturation of 90 to 94 percent. The major pharmacologic components of managing an acute exacerbation of COPD include inhaled short-acting bronchodilators (beta adrenergic agonists and anticholinergic agents), glucocorticoids, and antibiotics. 

• Beta adrenergic agonists - Inhaled short-acting beta adrenergic agonists (albuterol) are the mainstay of therapy for an acute exacerbation of COPD because of their rapid onset of action and efficacy in producing bronchodilation.
• Anticholinergics - Inhaled short-acting anticholinergic agents (ipratropium) may be used in combination with inhaled short-acting beta adrenergic agonists. 
• Glucocorticoids - Systemic glucocorticoids, when added to the bronchodilator therapies described above, improve symptoms and lung function, and decrease the length of hospital stay. The route used depends on the stability of the patient. Oral glucocorticoids are rapidly absorbed and appear equally efficacious as intravenous glucocorticoids. In fact, a randomized trial assigned 210 patients hospitalized with a COPD exacerbation to receive oral or IV steroids for five days and found no difference between the two groups in the rate of treatment failure, length of hospital stay, improvement in spirometry, or improvement in quality of life. However, intravenous glucocorticoids are typically administered to patients who present with a severe exacerbation, who respond poorly to oral glucocorticoids or who are unable to take oral medication. 
• Antibiotics - The optimal antibiotic regimen for the treatment of exacerbations of COPD has not been determined. UpToDate recommends a "risk stratification" approach when selecting initial antibiotic therapy (see algorithim below). Specifically, they recommend prescribing a broader antibiotic regimen for patients who have risk factors for a poor outcome.