Chronic obstructive pulmonary disease (COPD) is comprised primarily of three related conditions – chronic bronchitis, chronic asthma, and emphysema.

In each condition there is chronic obstruction of the flow of air through the airways and out of the lungs, and the obstruction generally is permanent and may be progressive over time.

While asthma features obstruction to the flow of air out of the lungs, usually, the obstruction is reversible.
Between “attacks” of asthma the flow of air through the airways typically is normal.

These patients do not have COPD. However, if asthma is left untreated, the chronic inflammation associated with this disease can cause the airway obstruction to become fixed.

That is, between attacks, the asthmatic patient may then have abnormal air flow. This process is referred to as lung remodeling.

These asthma patients with a fixed component of airway obstruction are also considered to have COPD.

Often patients with COPD are labeled by the symptoms they are having at the time of an exacerbation of their disease.
For instance, if they present with mostly shortness of breath, they may be referred to as emphysema patients, While if they mostly have cough and mucus production, they are referred to as having chronic bronchitis.

Thus, patients with emphysema may have some of the characteristics of chronic bronchitis and chronic asthma and vice a versa.

Chronic bronchitis:
Chronic bronchitis involves inflammation and swelling of the lining of the airways that leads to narrowing and obstruction of the airways.

The inflammation also stimulates production of mucous (sputum), which can cause further obstruction of the airways.
Obstruction of the airways, especially with mucus, increases the likelihood of bacterial lung infections.
Chronic bronchitis usually is defined clinically as a daily cough with production of sputum for three months, two years in a row.

Emphysema:
There is permanent enlargement of the alveoli due to the destruction of the walls between alveoli in emphysema.
The destruction of the alveolar walls reduces the elasticity of the lung overall.
Loss of elasticity leads to the collapse of the bronchioles obstructing airflow out of the alveoli.
Air becomes “trapped” in the alveoli and reduces the ability of the lung to shrink during exhalation.
This trapped air takes up space and results in a reduced amount of air that can be taken in during the next breath.
As a result, less air gets to the alveoli for the exchange of gasses.
This trapped air also can compress adjacent less damaged lung tissue, preventing it from functioning to its fullest capacity.
The exchange of carbon dioxide and oxygen between air and the blood in the capillaries takes place across the thin walls of the alveoli.
Destruction of the alveolar walls decreases the number of capillaries available for gas exchange leading to decrease in the ability to exchange gases.
However, in emphysema, inefficient breathing occurs because extra effort and energy has to be expended to empty the lungs of air due to the collapse of the airways.
This essentially doubles the work of breathing, since now energy is required for both inhalation and exhalation.
In addition, because of the reduced capacity to exchange gases with each breath (due to the collapse of the bronchioles and loss of capillaries), it is necessary to breathe more frequently.

Chronic asthma:
Asthma, like chronic bronchitis, is a disease of the airways.
Obstruction to the flow of air is due to inflammation of the airways as well as spasm of muscles surrounding the airways in asthma.
The narrowing that results from spasm of the muscles is called bronchospasm.
Generally, bronchospasm in asthma is reversible and subsides spontaneously or with the use of bronchodilators (medications that relax the muscles surrounding the airways).
Major component of asthma is inflammation of the airways, and this inflammation causes thickening of the walls of the airways.
This inflammation involves different inflammatory cells and mediators than those seen in chronic bronchitis.
In many asthmatics, antiinflammatory medications such as inhaled steroids are required to reduce this inflammation.
In long standing asthma, this chronic inflammation can lead to scarring and fixed airway obstruction.

Causes:
Cigarette smoking
Effects of passive smoking or “second-hand smoke”
Air pollution
Occupational pollutants
Symptoms:

Author Bio: steven is associated with dermatology billing services and cardiology billing services and medical coding training and ICD10 Certification

Category: Medicines and Remedies
Keywords: dermatology, billing, services