April 15, 2011
Dear Mayo Clinic:
What causes chronic bronchitis? Is there a cure?
Bronchitis is an inflammation of the lining of the tubes that carry air to and from the lungs (bronchial tubes). Symptoms include coughing, phlegm production, and wheezing. Chronic bronchitis is defined by how long a person has a cough with daily phlegm production. It involves a frequent cough that persists for more than two years and, for at least three continuous months, produces phlegm. This is an important definition since the term chronic bronchitis implies a specific medical diagnosis. This should not be confused with a cough that may linger for several weeks or months after a cold(post-infectious cough). Other causes of prolonged cough are postnasal drip, acid reflux or asthma. Rarely, it can be due to lung cancer, a bacterial infection or aspiration pneumonia.
The most common cause of chronic bronchitis is smoking. Unlike a post-infectious cough or viral bronchitis — which usually clear up over time with little or no treatment — chronic bronchitis is a serious, ongoing disorder that involves long-term inflammation, irritation and thickening of the bronchial tubes. In some people, chronic bronchitis may be a component of chronic obstructive pulmonary disease (COPD), a lung disorder associated with reduced airflow when a person exhales. In addition to a cough, COPD is typically accompanied by shortness of breath, especially with exertion.
Many conditions can cause a persistent cough that mimics chronic bronchitis. People who have a persistent cough need to be carefully evaluated for asthma, lung cancer, allergies, acid reflux and sinus disease, especially if they are current nonsmokers. If an underlying respiratory condition is the source of the problem, treating that condition should improve the chronic cough.
Treatment of chronic bronchitis varies, depending on the cause. Since smoking is the most common cause, current smokers should quit. In some people who develop COPD, the bronchial inflammation of chronic bronchitis may persist even after a smoker quits. Typically, though, once a person stops smoking, the cough and the mucus production recede over time, although it may take several months.
In those who have chronic bronchitis with COPD, it is not unusual to be at risk for sudden worsening of cough, shortness of breath, change in the character of phlegm production and bronchial infection. Developing one or more of these symptoms is known as an acute exacerbation of chronic bronchitis. Early diagnosis and treatment of an acute exacerbation is important. Treatment may include antibiotics to fight infection, prednisone to reduce inflammation, and bronchodilators to open up the airways.
Many over-the-counter cough suppressants and mucolytic medications can help to relieve symptoms of chronic bronchitis. These medications may help temporarily, but research studies have shown that they do not provide lasting benefit.
Treatment of chronic bronchitis that is part of COPD can be more complicated than chronic bronchitis from other causes. Although COPD cannot be cured, it can be managed. Emphysema and chronic asthmatic bronchitis are the two main conditions that make up COPD. In COPD, damage to the airways eventually interferes with the exchange of oxygen and carbon dioxide in the lungs. This damage can't be reversed, so treatment focuses on controlling symptoms and minimizing further damage. Medications, such as bronchodilators to relax the muscles around the airways and inhaled steroids to reduce airway inflammation, can help make breathing easier and reduce coughing.
If you think you may have chronic bronchitis, talk to your doctor. It's important to determine the cause and develop a treatment plan that fits your situation. If you smoke and have chronic bronchitis, quit. If you need help quitting, ask your doctor to recommend a reputable smoking cessation program.
— Kaiser Lim, M.D., Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, Minn.