chronic obstructive pulmonary disease
Meaning of chronic obstructive pulmonary disease: The problem is emptying rather than filling: air enters well enough but cannot get back out of a lung that has lost its recoil.
Definition of chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease is a long-term lung condition in which airflow out of the lungs is persistently limited and never returns to normal. Damage to the airways and to the air sacs, usually built up over years of inhaled smoke or dust, narrows the passages and destroys the elastic tissue that empties them. Breathlessness, a lasting cough and sputum develop gradually.
What are the two halves of the disease?
| Component | What changes | Main effect |
|---|---|---|
| Chronic bronchitis | Airway lining inflamed and thickened, mucus glands enlarged | Daily cough with sputum, and narrowed passages |
| Emphysema | Walls between neighboring air sacs break down | Lost surface area and lost elastic recoil |
Most people carry both in some proportion rather than one alone. Bronchitis narrows the tube, while emphysema takes away the spring that squeezes air back out of it and also removes the tethering that holds small airways open, so those airways collapse during exhalation. Stale air is left behind after every breath, the chest sits progressively overinflated, and breathing becomes hard work even at rest as the disease advances.
What causes it?
Tobacco smoke accounts for the great majority of cases where smoking is common, and risk rises with both the amount smoked and the years spent smoking. Smoke from indoor cooking and heating fires is a major cause worldwide, particularly among women, and involves no tobacco at all. Occupational dust, fumes and vapors contribute, as do severe chest infections in childhood and lungs that never reached full size. A small share of cases trace to alpha-1 antitrypsin deficiency, an inherited shortage of a protein that shields lung tissue from the body's own enzymes, which produces emphysema unusually early.
How is it recognized and measured?
Symptoms cannot establish it on their own, because breathlessness and cough have many sources. The diagnosis rests on a breathing measurement showing airflow that stays obstructed after a reliever inhaler, and that persistence is what separates it from asthma. A PFT supplies the measurement and also tracks the disease over time. Flare-ups, called exacerbations, punctuate the illness: over days the cough worsens, sputum changes in color or volume and breathing deteriorates, usually set off by infection or by polluted air. Severe flare-ups tend to leave lung function lower than it was before, and the condition is progressive rather than reversible.
Also known as
Used in a sentence
Chronic obstructive pulmonary disease was confirmed by spirometry showing persistent airflow obstruction.
Good to know
Airflow limitation here persists after a reliever inhaler, which is the feature separating it from asthma, and diagnosis made on symptoms alone without a breathing measurement is a recognized source of both over-diagnosis and under-diagnosis.
Word origin
Where “chronic obstructive pulmonary disease” comes from
Pulmonary comes from the Latin pulmo, meaning lung, and chronic from the Greek chronos, meaning time.