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Bronchiectasis
is an irreversible widening (dilation) of portions of the airways
(bronchi) resulting from damage to the bronchial wall.
Bronchiectasis can result from several conditions that injure the bronchial wall directly or indirectly by interfering with its normal defenses against potentially harmful substances (see Biology of the Lungs and Airways: Defense Mechanisms). The most common cause is severe respiratory infections. Immune deficiency disorders, hereditary disorders (such as cystic fibrosis, in which abnormal mucus impairs the ability of cilia to clear the bronchi of organisms that cause infections (see Cystic Fibrosis (CF))), and mechanical factors (such as bronchial obstruction caused by an inhaled object, a lung tumor, or other disorders) may predispose a person to infections that lead to bronchiectasis. A small number of cases probably result from inhaling toxic substances that injure the bronchi, such as noxious fumes, gases, smoke (including tobacco smoke), and injurious dust (silica, coal dust).
In bronchiectasis, areas of the bronchial wall are destroyed and become chronically inflamed, ciliated cells are damaged or destroyed, and secretions (mucus) accumulate. Also, the bronchial wall becomes less elastic—the affected airways become wider and flabby and may develop outpouchings or sacs that resemble tiny balloons. The increased mucus production promotes the growth of bacteria, often obstructs the bronchi, and leads to pooling of infected secretions and further damage to the bronchial wall. The inflammation and infection can extend to the small air sacs of the lungs (alveoli) and produce pneumonia, scarring, and a loss of functioning lung tissue.
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Understanding Bronchiectasis
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In bronchiectasis, mucus production increases, the cilia are destroyed or damaged, and areas of the bronchial wall become chronically inflamed and are destroyed.
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In severe cases, scarring and a loss of blood vessels in the lung can ultimately strain the right side of the heart as the heart tries to pump blood through the altered vessels. Also, inflammation and an increased number of blood vessels in the bronchial wall (which are fragile) can result in a person coughing up blood. Blockage of the damaged airways can lead to abnormally low levels of oxygen in the blood.
Bronchiectasis may affect many areas of the lung, or it may appear in only one or two areas. Typically, bronchiectasis causes widening of medium-sized bronchi, but often smaller bronchi become scarred and destroyed. Occasionally, a form of bronchiectasis affecting larger bronchi occurs in allergic bronchopulmonary aspergillosis, a condition caused by an allergic response to the Aspergillus fungus (see Allergic and Autoimmune Diseases of the Lungs: Allergic Bronchopulmonary Aspergillosis).
Symptoms
Bronchiectasis can develop at any age; often, the process 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 how extensive the disease is and whether there is a complicating infection. Often, the person has coughing spells only early in the morning and late in the day. Coughing up of blood is common and 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; they may also have chronic bronchitis, emphysema, or asthma. Very severe cases of bronchiectasis, which occur more commonly in underdeveloped countries and in people who have advanced cystic fibrosis, may impair breathing and the lung's ability to oxygenate the blood and rid the body of carbon dioxide, a condition called respiratory failure (see Respiratory Failure and Acute Respiratory Distress Syndrome: Respiratory Failure). Very severe bronchiectasis may also strain the right side of the heart and lead to cor pulmonale (see Cor Pulmonale: A Disorder Stemming From Pulmonary Hypertension ).
Diagnosis
Doctors may suspect bronchiectasis because of a person's symptoms or the presence of a condition thought to cause bronchiectasis. Tests are performed 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, results are normal. Computed tomography (CT) is usually the most sensitive test to identify and confirm the diagnosis and to determine the extent and severity of the disease; these are important factors when surgical treatment is being considered.
After bronchiectasis is diagnosed, tests are often performed to check for diseases that may be causing or contributing to it if they were previously not identified. Such tests may include measuring the immunoglobulin levels in blood, testing for HIV infection and other immune system disorders, measuring the salt levels in sweat (which are abnormal in people with cystic fibrosis), and examining nasal, bronchial, or sperm specimens with a special microscope and other tests to determine if the cilia are structurally or functionally defective. When bronchiectasis is limited to one area—for example, a lung lobe or segment—doctors may perform bronchoscopy (see Symptoms and Diagnosis of Lung Disorders: Bronchoscopy) to determine whether an inhaled foreign object or lung tumor is the cause. Other tests may be performed to identify underlying diseases, 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 suspicious findings in a child or young adult, even when other typical features of cystic fibrosis are absent.
Prevention
Early identification and treatment of conditions that tend to cause bronchiectasis may prevent the development of bronchiectasis 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, appropriate use of antibiotics, and improved living conditions and nutrition have significantly reduced the number of people who develop bronchiectasis. Annual influenza vaccines, use of the pneumococcal vaccine, and use of appropriate drugs early in the course of infections (such as pneumonia and tuberculosis) 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 carefully watching what they put in their mouth. Additionally, avoiding oversedation 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 other oils should never be placed in the mouth or nose because they can be inhaled into the lungs.
Treatment and
Prognosis
Treatment of bronchiectasis is directed against eradicating infections, decreasing the build up of mucus and inflammation, relieving airway obstruction, and reducing complications (such as coughing up of blood, low oxygen levels in the blood, respiratory failure, and cor pulmonale). Drugs that suppress coughing may worsen the condition and generally should not be used.
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 buildup of mucus, anti-inflammatory drugs such as inhaled corticosteroids and drugs that thin the pus and mucus (mucolytics) 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 Symptoms and 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. Alternatively, a doctor may deliberately block a bleeding bronchial vessel by using a procedure called bronchial arterial embolization.
If the person's blood oxygen level is low, oxygen therapy (see Rehabilitation for Lung and Airway Disorders: Oxygen Therapy) may help prevent complications such as cor pulmonale. If the person has wheezing or shortness of breath, 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 performed in certain 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.
Overall prognosis for people with bronchiectasis depends on how well infection and other complications are prevented or controlled. Because other conditions (such as chronic bronchitis, emphysema, pulmonary hypertension, cor pulmonale, or other serious diseases that affect the whole body [systemic diseases]) diminish the effectiveness of prevention and treatment, people with these conditions tend to have a worse prognosis.
Last full review/revision February 2003
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