Clinical history and symptoms
Chronic obstructive pulmonary disease (COPD) typically presents in middle-aged and older people, usually with a history of exposure to noxious particles or gases. Tobacco smoking is the most important risk factor for COPD—approximately half of all smokers develop some degree of airflow limitation, and 15 to 20% develop clinically significant disability. Smoking and loss of forced expiratory volume in 1 second (FEV1) with age illustrates the accelerated decline in lung function seen in smokers compared with nonsmokers.
Not all patients with COPD have a history of smoking. Other risk factors include prenatal parental smoking, premature birth, respiratory illnesses in childhood, asthma, exposure to second-hand smoke, occupational exposure to dusts and fumes, and genetic susceptibility. In low- and middle-income countries, exposure to biomass smoke for heating and cooking is common.
Consider the possibility of COPD in all patients older than 35 years who are smokers or ex-smokers, or have other relevant risk factors, and present with symptoms suggestive of COPD, including:
- breathlessness
- cough
- recurrent respiratory tract infection
- sputum production
- wheezing.
Breathlessness may be the patient’s only symptom; it typically occurs only on exertion initially, but worsens insidiously over several years.
Some inherited conditions, most notably alpha1-antitrypsin deficiency, make patients more susceptible to the damaging effects of tobacco smoke, and lead to earlier development and more rapid progression of COPD. Alpha1-antitrypsin deficiency should be suspected if COPD develops at a young age (eg before 40 years), particularly if the patient has a family history of COPD. Refer young patients with COPD to a respiratory physician for assessment.
Although a medical history and symptoms can suggest COPD, a formal diagnosis cannot be made without spirometry; see Lung function measurement for more information.