Chronic obstructive pulmonary disease (COPD): Incidence, Symptoms, Causes, Risk Factors, Treatment

Chronic obstructive pulmonary disease (COPD) is a condition in which there is airflow limitation that leads to an abnormal inflammatory response of the lungs due to poisonous particles or gases that is not fully reversible.

Incidence Rate

COPD is the fifth leading cause of death in the UK and the fourth in the world. It is expected to rise to the third leading cause by 2020. It is estimated that over 2.5 million people have the disease in the UK, with 2.1 million having undiagnosed COPD.It is accountable for more than 10% of all hospital admissions and directly costs the NHS around £491 m/year.

Causes

Tobacco smoking is the most important and dominant risk factor in the development of COPD but other noxious particles also contribute, such as occupational exposure to chemical fumes, irritants, dust, and gases. A person’s exposure can be thought of in terms of the total burden of inhaled particles. These cause a (normal) inflammatory response in the lungs. Smokers, however, seem to have an exaggerated response which eventually causes tissue destruction and impaired repair mechanisms.

Risk factors

Smoking:

Risk increases with increasing consumption but there is also large interindividual variation in susceptibility

Age:

Increasing age results in ventilatory impairment; most frequently related to cumulative smoking

Gender:

Male gender was previously thought to be a risk factor but this may be due to a higher incidence of tobacco smoking in men. Women have greater airway reactivity and experience faster declines in FEV1, so may be at more risk than men

Occupation:

The development of COPD has been implicated with occupations such as coal and gold mining, farming, grain handling and the cement and cotton industries

Genetic factors:

α1 -Antitrypsin deficiency is the strongest single genetic risk factor, accounting for 1–2% of COPD. Other genetic disorders involving tissue necrosis factor and epoxide hydrolase may also be risk factors

Air pollution:

Death rates are higher in urban areas than in rural areas. Indoor air pollution from burning biomass fuel is also implicated as a risk factor, particularly in underdeveloped areas of the world

Socioeconomic status:

More common in individuals of low socioeconomic status

Airway hyperresponsiveness and allergy: Smokers show increased levels of IgE, eosinophils, and airway hyperresponsiveness but how these influence the development of COPD is unknown.

Diagnosis

A diagnosis of COPD should be considered in any patient who has symptoms of a cough, wheeze, regular sputum production or exertional dyspnoea and/or a history of exposure to COPD risk factors. Spirometry is the next procedure for the confirmation of the disease. There is no single diagnostic test used for the confirmation of COPD.

Investigational Tests For The Diagnosis of COPD

Chest X-ray: To exclude other pathologies

Full blood count: To identify anemia or polycythemia

Serial domiciliary peak flow measurements: To exclude asthma if there is a doubt about diagnosis

α1 -Antitrypsin: Particularly with early-onset disease or a minimal smoking/family history

Transfer factor for carbon monoxide: To investigate symptoms that seem disproportionate to the spirometric impairment

Thorax CT scan: To investigate abnormalities seen on the chest X-ray.

Echocardiogram: To know the cardiac status if features of cor pulmonale

Pulse oximetry: To assess the need for oxygen therapy If cyanosis or cor pulmonale is present or if FEV1 <50% of predicted value.

Sputum culture: This method is used if the organisms are present in sputum.

Treatment

Smoking cessation

Smoking is the most important factor in the development of obstructive airways disease. All COPD patients who still smokes, regardless of their age, should stop smoking as it can deteriorate the condition at every opportunity.
Bronchodilators

Bronchodilators in COPD are used to reverse airflow limitation.

Short-acting bronchodilators (short-acting b2 -adrenoceptor agonist or short-acting antimuscarinic). Selective β2 -agonists provide rapid relief and have a low incidence of side effects. Inhaled treatment is as efficacious as oral agents and is, therefore, preferred because of fewer side effects.

Long-acting bronchodilators. Long-acting bronchodilators include LAMAs and LABAs. The only LAMA in the UK, tiotropium, has a 24-h duration of action and can reduce exacerbation rates, increase exercise tolerance and reduce rates of hospital admissions, though not the rate of decline in lung function.

High-dose bronchodilators. Some patients with distressing or debilitating breathlessness despite maximal inhaled therapy may benefit from higher doses, either by inhaler or via a nebulizer.

Theophylline. Theophylline is a weak bronchodilator but seems to have useful additional physiological effects in COPD