COPD - short for chronic obstructive pulmonary disease - is a chronic lung condition that is usually associated with tobacco smoking.
Contents of this article:
Here are some key points about COPD. More detail and supporting information is in the main article.
- COPD is a group of diseases that includes chronic bronchitis and emphysema
- Most cases of COPD are a result of tobacco smoking
- Symptoms of COPD include shortness of breath, coughing and production of sputum
- COPD is a progressive and incurable disease, and the third largest cause of death in the US
- In 2010, more than 70,000 women died of COPD in the US, compared to more than 64,000 males11
- A single symptom of COPD (such as cough, shortness of breath) often arises long before other symptoms.
- The lungs of people with COPD suffer structural damage that causes the tiny air sacs to enlarge and become less efficient
- Diagnosis is confirmed by a clinical test called spirometry, which measures by how much the breathing is limited
- The main way to prevent COPD developing is to avoid smoking
- Any patient with COPD can benefit from smoking cessation and there are medical interventions, including drugs, to help with this
- COPD cannot be reversed but its symptoms can be eased by drug treatment
- Drug treatments are usually inhaled, and most act as bronchodilators through muscle relaxation to ease breathing by opening up the lungs
- Other therapy options include pulmonary rehabilitation, oxygen therapy, and surgery
- Exacerbations and complications of COPD are an unusual worsening of symptoms and can be life-threatening. Healthcare professionals help patients to prevent complications as far as possible.
What is COPD?
COPD is irreversible and most often caused by smoking.
COPD stands for chronic obstructive pulmonary disease:
- Chronic because it is ongoing - it persists lifelong without being fully reversible
- Obstructive because normal breathing capacity is restricted
- Pulmonary because it pertains to the lungs - it is a respiratory disease.
Chronic bronchitis is continual irritation and inflammation of the lining of the lungs, causing them to thicken and secrete mucus. The diagnosis is made if cough or mucus production persists for long enough.4
Emphysema is damage to the structure of the lung in which the walls of the air sacs are destroyed, making the air spaces larger and less efficient.4
The airflow limitation in COPD is usually progressive - it gets worse over time - and is associated with an abnormal inflammatory response of the lungs to noxious particles or gases.4 The condition does not change much over the course of several months.3
Leading cause of illness and death
The American Lung Association says COPD is the third-leading cause of death in the US, claiming the lives of 134,676 Americans in 2010.11
The World Health Organization (WHO) has estimated that prevalence of COPD in the US rose by 41% between 1982 and 1994, with death rates going up by 71% between 1966 and 1985. It also estimates that COPD is responsible for 4.8% of all deaths - or an estimated 2,745,816 deaths in 2002.4
In 2011, 12.7 million US adults (aged 18 and over) were estimated to have COPD, but almost 24 million adults in the US have evidence of impaired lung function, suggesting that COPD is underdiagnosed.12,13
Increasingly, women are more likely to be affected by COPD, with 2010 the eleventh year in which rates of COPD-related deaths in women have exceeded deaths in men.11 In fact, women are twice as likely as men to be diagnosed with chronic bronchitis, and more women than men are now diagnosed with emphysema (a disease that was historically more prevalent in men).
The 2011 statistics for men and women are as follows:13
- Chronic bronchitis - 3.3 million men/6.8 million women
- Emphysema - 2.1 million men/2.6 million women.
A 2013 report from the European Respiratory Society says the number of people living with COPD will continue to rise.
Anatomy of COPD lung disease
The deepest part of the lungs end in tiny air sacs, where gases enter and leave tiny blood vessels. The walls of these sacs are damaged in COPD.
In COPD, the chief site of damage to the anatomy of the lungs occurs in the small airways - the deepest part of the lung tissue which contains no cartilage and where the internal diameter of the tubes is less than two millimetres.6
The normal anatomy of the normal lungs is designed to maximise the surface area over which gaseous exchange can occur. This is why the tubes branch off into smaller and smaller diameters, leading to a large number of tiny air sacs.
The larger the total surface area of the membrane between air sacs and blood vessels, the greater the efficiency of gaseous exchange, whereby oxygen can enter the circulation and carbon dioxide can leave it. The more sacs, the greater the surface area.
In COPD, the air sacs become larger and less numerous because of the breakdown of their walls, reducing the overall surface area of the air-blood barrier (or alveolar-capillary barrier - the air sacs are called alveoli and the small blood vessels are called capillaries).
Doctors are shown summarizing COPD in the short video below from YouTube, produced by the pharmaceutical company Novartis.
On the next page, we look at the causes, symptoms and diagnosis of COPD