Chronic Obstructive Pulmonary Disease

INTRODUCTION

Chronic bronchitis and emphysema should be considered together as both conditions usually coexist to some degree in each patient. An alternative, and preferable, term—chronic obstructive airway or pulmonary disease (COPD)—is used to cover chronic bronchitis and emphysema with chronic airflow limitation.

It is defined as a common preventable and treatable disease of persistent airflow limitation associated with an enhanced chronic inflammatory response to noxious particles or gases. Exacerbations and comorbidities contribute to the overal severity in individual patients.

FACTORS IN CAUSATION

• Cigarette smoking: usu. 20/d for 20 yrs

• Air pollution/occupational exposure, e.g. coal, bauxite, cadmium

• Airway infection

• Familial factors: genetic predisposition

• Alpha₁-antitrypsin deficiency—autosomal recessive (emphysema)

SYMPTOMS

• Onset in 5th or 6th decade

• Wheeze (chronic bronchitis)

• Chest tightness

• Susceptibility to colds

INVESTIGATIONS

Chest X-ray: can be normal (even with advanced disease) but characteristic changes occur late in disease.

Pulmonary function tests (spirometry is gold standard):

• peak expiratory flow rate—low with minimal response to bronchodilator (not sensitive)

• ratio FEV₁/FVC—reduced with minimal response to bronchodilator

• gas transfer coefficient of CO is low if significant emphysema

Blood gases:

• may be normal

• PaCO₂ ↑; PaO₂ ↓ (advanced disease)

• Gas transfer factor

MANAGEMENT

Advice to the patient

• Reduce risk factors

• If you smoke, you must stop: this is the key to management

• Avoid places with polluted air and other irritants, such as smoke, paint fumes and fine dust

• Go for walks in clean, fresh air

• A warm dry climate is preferable to a cold damp place (if prone to infections)

• Get adequate rest

• Update immunisation—annual influenza, pneumococcus

• Avoid contact with people who have colds and flu

PHYSIOTHERAPY

Refer symptomatic patients for pulmonary rehabilitation—chest physiotherapy, breathing exercises and an aerobic physical exercise program.

DRUG THERAPY

Consider the use of bronchodilators (e.g. inhaled β₂-agonists) and inhaled corticosteroids, because of associated (often unsuspected) asthma. A carefully monitored trial of these drugs with FEV measurement is recommended. Fixed dose combinations of LABA and inhaled corticosteroids ICS (Seretide, Symbicort or Flutiform) may be used for patient convenience.

Triple therapy with tiotropium (a long-acting muscarinic antagonist [LAMA]) plus an ICS/LABA agent is usual practice for moderate to severe COPD. Corticosteroids should be used routinely for acute exacerbations. Use:

• prednisolone 30–50 mg (o)/d

If not tolerated orally use:

• hydrocortisone 100 mg IV 6 hrly (or ...