Chronic Bronchitis

  • Basics

    Chronic bronchitis is a long-term, often irreversible respiratory illness. Those with chronic bronchitis have a daily mucus-producing cough that persists for at least 3 months a year, at least 2 years in a row.

    Bronchitis is an inflammation of the lining of the air passages. Bronchitis can be classified as acute or chronic. Acute bronchitis is a mild inflammation of the air passages of the lungs that clears up within a few days, often without treatment. Chronic bronchitis is a persistent, serious lung disease that requires ongoing medical care and can lead to gradual deterioration of the lungs. Many people with chronic bronchitis also develop another respiratory disease called emphysema.

    Chronic bronchitis involves restriction of airflow in the air passages that worsens over time. This causes increasing difficulty in breathing and more sputum (mucus) production in the lungs.

    Chronic bronchitis is a form of chronic obstructive pulmonary disease (COPD), a serious health condition.

    COPD is the fourth-leading cause of death in the United States. About 11 million American adults suffer from COPD.

    The diseases that fall under the COPD “umbrella” all lead to some type of long-term airflow problem in the lungs. The most common COPD conditions are chronic bronchitis, emphysema, and chronic asthmatic bronchitis. These may occur by themselves, but often a person has more than one condition occurring at the same time.

    Chronic bronchitis, like other COPD conditions, can have episodes where symptoms get worse very quickly. These episodes are called exacerbations, and they can vary in degree of severity.

    Exacerbations of chronic bronchitis can be triggered by upper- or lower-airway infections, such as colds or influenza. Exposure to environmental irritants, such as dust, fumes, or air pollution, may also exacerbate chronic bronchitis. Other medical conditions, such as heart problems or infection elsewhere in the body, can worsen chronic bronchitis symptoms. Exacerbations can be serious and even life threatening.

  • Causes

    Smoking is the major cause of chronic bronchitis and other chronic obstructive pulmonary diseases (COPDs).

    Cigarette smoking causes approximately 80%-90% of COPD cases. Inhaling smoke temporarily paralyzes the tiny, hair-like cells called cilia that line the air passages of the lungs. These cilia are important because they help to keep germs and irritants out of the lungs. The more you smoke, the more damage you do to the cilia.

    When the cilia do not work properly, mucus stays trapped in the lungs. This causes the walls of the bronchial tubes to become irritated, swell, and narrow. The bronchial tubes also become less able to expand when the body needs more oxygen. Mucus stuck in the smaller passages causes stale air to be trapped instead of exhaled. This leads to difficulty breathing that becomes progressively worse over time. The walls of the air sacs (alveoli) in the lungs also suffer damage as the disease progresses. As air sacs are destroyed, the lungs become less able to send oxygen to the bloodstream.

    Exposure to occupational or environmental irritants can cause chronic bronchitis.

    If you work around dust or fumes, know and follow the safety precautions recommended in the Material Safety Data Sheet(s) of the products or substances. Let your clinician know what you are exposed to in your work environment. If your bronchitis gets worse because of exposure to irritants in your workplace, you may need to change employment.

    Irritants may include:

    • Smoke
    • Air pollution irritants, such as ozone and nitrogen dioxide
    • Fumes from chemicals such as sulfur dioxide, hydrogen sulfide, bromine, strong acids, ammonia, some organic solvents, and chlorine
    • Dusts, such as coal dust or grain dust

    Chronic bronchitis can develop from repeated episodes of acute bronchitis or other repeated lung infections.

    The recurring cough from repeated episodes of acute bronchitis may damage the lining of the bronchial tubes, making it increasingly difficult to clear mucus from the lungs. The mucus then leads to further coughing and more scarring of the air passages in the lungs. Chronic bronchitis may develop over time because of this damage. Recurrent respiratory tract infections during infancy or early childhood can also lead to chronic bronchitis.

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