Bronchiectasis is an irreversible widening (dilation) of portions of the breathing tubes or airways (bronchi) resulting from damage to the airway wall.
Bronchiectasis can result when conditions directly injure the bronchial wall or indirectly lead to injury by interfering with normal airway defenses. Airway defenses include tiny projections (cilia) on the cells that line the airways. These cilia beat back and forth, moving the thin liquid layer of mucus that normally coats the airways. Harmful particles and bacteria trapped in this mucus layer are moved up to the throat and coughed out or swallowed.
Whether airway injury is direct or indirect, areas of the bronchial wall are damaged and become chronically inflamed. The inflamed bronchial wall becomes less elastic, resulting in the affected airways becoming wider and flabby and developing small outpouchings or sacs that resemble tiny balloons. Inflammation also increases secretions (mucus). Because cells with cilia are damaged or destroyed, these secretions accumulate in the widened airways and serve as a breeding ground for bacteria. The bacteria further damage the bronchial wall, leading to a vicious circle of infection and airway damage.
Bronchiectasis may affect many areas of the lung (diffuse bronchiectasis), or it may appear in only one or two areas (focal bronchiectasis). Typically, bronchiectasis causes widening of medium-sized airways, but often smaller airways become scarred and destroyed.
The inflammation and infection can extend to the small air sacs of the lungs (alveoli) and cause pneumonia, scarring, and a loss of functioning lung tissue. Severe scarring and loss of lung tissue can ultimately strain the right side of the heart as the heart tries to pump blood through the altered tissue. The right-sided heart strain can lead to a form of heart failure called cor pulmonale (see Pulmonary Hypertension: Pulmonary Hypertension).
Very severe cases of bronchiectasis, which occur more commonly in underdeveloped countries and in people who have advanced cystic fibrosis, may impair breathing enough to cause abnormally low levels of oxygen and high levels of carbon dioxide in the blood, a condition called respiratory failure (see Respiratory Failure and Acute Respiratory Distress Syndrome: Respiratory Failure).
The most common cause is severe or repeated respiratory infections. Other causes include
Occasionally, a condition that affects larger airways, called allergic bronchopulmonary aspergillosis, occurs in people with asthma. Allergic bronchopulmonary aspergillosis (see Allergic and Autoimmune Diseases of the Lungs: Allergic Bronchopulmonary Aspergillosis) is an allergic reaction to the Aspergillus species, which is a fungal organism. It can cause mucus plugs that obstruct the airways and lead to bronchiectasis.
Bronchiectasis can develop at any age, but the process often begins in early childhood. However, symptoms may not appear until much later. In most people, symptoms begin gradually, usually after a respiratory infection, and tend to worsen over the years. Most people develop a chronic cough that produces sputum. The amount and type of sputum depend on the extent of the disease and whether there is a complicating infection. Often, people have coughing spells only early in the morning and late in the day. Coughing up of blood (hemoptysis) is common because the damaged airway walls are fragile and have increased numbers of blood vessels. Hemoptysis may be the first or only symptom.
Recurrent fever or chest pain, with or without frequent bouts of pneumonia, may also occur. People with widespread bronchiectasis may develop wheezing or shortness of breath. People whose bronchiectasis progresses to cor pulmonale or respiratory failure also have fatigue, lethargy, and worsening shortness of breath, particularly with exertion.
Doctors may suspect bronchiectasis because of a person's symptoms or the presence (currently or in the past) of a condition thought to cause bronchiectasis. Tests are done to confirm the diagnosis and assess the extent and location of the disease. Chest x-rays can often detect the lung changes caused by bronchiectasis. However, occasionally, x-ray results are normal. Computed tomography (CT) is the most sensitive test to identify and confirm the diagnosis and to determine the extent and severity of the disease.
After bronchiectasis is diagnosed, tests are often done to check for disorders that may be causing or contributing to it. Such tests may include the following:
When bronchiectasis is limited to one area—for example, a lung lobe or segment—doctors may do a bronchoscopy (see Diagnosis of Lung Disorders: Bronchoscopy) to determine whether an inhaled foreign object or lung tumor is the cause. Other tests may be done to identify underlying disorders, such as allergic bronchopulmonary aspergillosis or tuberculosis.
Genetic testing for cystic fibrosis may be needed when there is a family history, repeated respiratory infections, or other unusual findings in a child or young adult, even when other typical features of cystic fibrosis are absent.
Early identification and treatment of conditions that tend to cause bronchiectasis may prevent its development or reduce its severity. More than half the cases of bronchiectasis in children can be accurately diagnosed and promptly treated.
Childhood immunizations against measles and whooping cough, improved living conditions, and good nutrition have markedly reduced the number of people who develop bronchiectasis. Annual influenza vaccines, pneumococcal vaccine, and use of appropriate antibiotics early in the course of lung infections help to prevent bronchiectasis or reduce its severity. Receiving immunoglobulin for an immunoglobulin deficiency syndrome may prevent recurring infections. In people who have allergic bronchopulmonary aspergillosis, the appropriate use of corticosteroids and perhaps the antifungal drug itraconazole may reduce the bronchial damage that results in bronchiectasis.
Avoiding toxic fumes, gases, smoke, and injurious dusts also helps prevent bronchiectasis or reduce its severity. Inhalation of foreign objects into the airways by children may be prevented by watching what they put in their mouth. Avoiding over-sedation from drugs or alcohol and seeking medical care for neurologic symptoms (such as impaired consciousness) or gastrointestinal symptoms (such as difficulty in swallowing and regurgitation or coughing after eating) may help to prevent aspiration. Also, drops of mineral oil or petroleum jelly should never be placed in the nose because they can be inhaled into the lungs.
Treatment and Prognosis
Treatment of bronchiectasis is directed toward eradicating infections, decreasing the build-up of mucus and inflammation, and relieving airway obstruction. Drugs that suppress coughing may worsen the condition and generally should not be used. Early, effective treatment can reduce complications such as hemoptysis, low oxygen levels in the blood, respiratory failure, and cor pulmonale.
Infections are treated with antibiotics, bronchodilators, and physical therapy to promote drainage of secretions. Sometimes antibiotics are prescribed for a long period to prevent recurring infections, especially in people who have cystic fibrosis.
For inflammation and the build-up of mucus, anti-inflammatory drugs such as inhaled corticosteroids and drugs that thin the pus and mucus (mucolytics and saline) may also be given, although the effectiveness of mucolytics is uncertain. To help drain the mucus, postural drainage and chest percussion (see Rehabilitation for Lung and Airway Disorders: Postural drainage) are used.
To detect and treat a bronchial obstruction, bronchoscopy can be used before severe damage occurs (see Diagnosis of Lung Disorders: Bronchoscopy). Rarely, part of a lung needs to be surgically removed. Such surgery usually is an option only if the disease is confined to one lung or, preferably, to one lung lobe or segment. Surgery may be considered for people who have recurrent infections despite treatment or who cough up large amounts of blood. Occasionally, doctors use a technique called embolization instead of surgery to stop bleeding in people who have a significant amount of bleeding when they cough. Doctors use a catheter to inject a substance that blocks the vessel that is bleeding. If people have low blood oxygen levels, doctors give oxygen therapy (see Rehabilitation for Lung and Airway Disorders: Oxygen Therapy). Appropriate use of oxygen may help prevent complications such as cor pulmonale. If people have wheezing or shortness of breath, oral and inhaled corticosteroids taken with or without bronchodilators often help. Respiratory failure, if present, should be treated (see Respiratory Failure and Acute Respiratory Distress Syndrome: Respiratory Failure).
Lung transplantation can be done in some people who have advanced bronchiectasis, mostly those who also have advanced cystic fibrosis. Five-year survival rates as high as 65 to 75% have been reported when a heart-lung or a double lung transplantation is used. Pulmonary function (as measured by the amount of air in the lungs and the rate and amount of air moving in and out of the lungs with each breath) usually improves within 6 months, and the improvement may be sustained for at least 5 years.
Prognosis for people with bronchiectasis depends on how well infections and other complications are prevented or controlled. People with co-existing conditions, such as chronic bronchitis or emphysema, and people who have complications, such as pulmonary hypertension or cor pulmonale, tend to have a worse prognosis.
Last full review/revision February 2008 by Joshua O. Benditt, MD