User:DayWalsh/Background - What is COPD?

What is COPD?
Chronic Obstructive Pulmonary Disease (COPD) is defined by the Global Obstructive Lung Disease group as a disease state charachterised by airflow limitation that is not fully reversible, unlike asthma. The air flow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases.

COPD usually presents in mid-life (around 40 years and onwards) with slowly progressive symptoms COPD generally arises following a long smoking history and results in a largely irreversible airflow limitation.

Smoking
Cigarette smoking causes the majority of COPD cases. Cigarette smoke is thought to release enzymes that damage a protein called elastin, which makes the lungs elastic. Smoking is also believed to inactivate alpha-1 antitrypsin (AAT), a protein produced by the liver that normally protects elastin from the action of these enzymes.

Environmental Exposure
COPD can also occur in people who have had long-term exposure to things that irritate your lungs, like certain chemicals, dust, or fumes in the workplace. Occupational exposure may be responsible for 20 - 30% of COPD. Heavy or long-term exposure to second-hand smoke or other air pollutants may also contribute to COPD.

Genetic Factors
In some people, COPD is caused by a genetic condition known as alpha-1 antitrypsin (AAT) deficiency. People with this AAT deficiency can develop COPD even if they have never smoked or had long-term exposure to harmful pollutants before. In these susceptible individuals, exposure to noxious gases or particles can result in chronic inflammation with tissue injury, ineffective repair and structural changes

Gender Factors
Some studies have shown that women may be at greater risk than men of COPD from exposures at work and are more susceptible to COPD due to smaller lungs and airways and more sensitive airways.

Forms of COPD
COPD can generally be classified into one of two groups: Chronic Bronchitis or Emphysema (multiple forms).

Chronic Bronchitis
Chronic Bronchitis is a recurrent problem, defined as the presence of cough and sputum production for at least 3 months in each of 2 consecutive years. The condition reduces the diameter of the airways through a combination of airway inflammation and overproduction of mucus. Chronic bronchitis is more prevalent in women than in men.

Emphysema
Emphysema is defined in structural and pathological terms as the abnormal and permanent enlargement of air spaces distal to the terminal bronchioles accompanied with destruction of their walls. In emphysema, the /alveoli/ are gradually destroyed so people have difficulty absorbing enough oxygen. The /bronchi/ become inelastic and narrow making it harder to breathe in and out (26 & 29). These days, smoking is the most common cause of emphysema. It is also most prevalent among men aged over 65 years.