Chapter 83: Chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is described by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as a ‘common, preventable and treatable disease characterised by non-fully reversible persistent airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways and the lung to noxious particles or gases. It is basically a structural disease. Exacerbations and comorbidities contribute to the overall severity in individual patients’.¹

COPD typically affects middle-aged and older people with the usual age of onset in the fifth and sixth decades. It is the fourth leading cause of death and the third leading burden of disease in Australia, affecting 12.4% of Australians between 45 and 70 years. Early diagnosis and treatment is important to outcome and the provisional diagnosis should be based on the clinical features of breathlessness and cough in a smoker or ex-smoker.

Cigarette smoking is undoubtedly the major cause of both chronic bronchitis and emphysema, although only 10–15% of smokers develop the diseases.² Chronic bronchitis is defined as >3 episodes per year for 2 years while emphysema is destruction of alveoli. The clinical differences between asthma and bronchitis are summarised in CHAPTER 49. Patients experiencing overlap of asthma and COPD should be identified and treated differently to patients with either condition alone.

Lifelong passive smoking exposure increases COPD risk by 2.2 to 4.0 times.

FIGURE 83.1 illustrates the influence of smoking on lung function.

FACTORS IN CAUSATION

• Cigarette smoking (usually 20/day for 20 years or more)⁴

• Natural fuel—wood, twigs, crop residue

• Air pollution (outdoor and indoor)

• Airway infection/chronic bronchitis

• Occupation: related to cadmium, silica, dusts

• Familial factors: genetic predisposition

• Alpha₁-antitrypsin deficiency (emphysema)

• Bronchial hyper-responsiveness

DIAGNOSIS AND MANAGEMENT OF COPD

The COPDX Plan guidelines⁵ developed by the Australian Lung Foundation and the Thoracic Society of Australia and New Zealand provide an appropriate framework for diagnosis and management. The key recommendations are: Confirm diagnosis, Optimise function, Prevent deterioration, Develop a self-management plan and manage eXacerbations.

C—Confirm diagnosis and assess severity

Symptoms