An uncommon but serious lung disorder
Most often secondary to childhood infection, bronchiectasis is irreversible. But there are steps you can take to improve your patients' quality of life.
Bronchiectasis, which is characterized by abnormal dilatation of the bronchi and excessive mucus production, is usually the result of acute or chronic infection.1 Thanks to the advent of effective anti-TB therapy and widespread childhood immunization against pertussis and measles, the number of diagnosed bronchiectasis cases has dropped in the past 50 years.2 However, the health-care community has become increasingly aware of bronchiectasis, mainly because high-resolution CT scans make diagnosing the condition much easier than it used to be.
Although most cases cannot be cured, treating underlying causes, initiating a regimen of bronchopulmonary hygiene, and prescribing appropriate antibiotic and inhaled medication can greatly ease patients' symptoms and improve their quality of life.
A vicious cycle
Bronchiectasis is the result of a vicious cycle of airway infection, inflammation, and structural damage. Infected airways become damaged by inflammatory mediators, resulting in impaired mucociliary clearance and increased bacterial colonization. Obstruction due to mechanical factors may also be a contributing factor.
A number of conditions have been associated with bronchiectasis (Table 1); however, in at least half of all cases, no definite cause or associated condition is identified.1, 3
Childhood infections are considered the most common etiologic factor. Besides pertussis and measles, other childhood respiratory tract infections, including pneumonia, may also damage the airways and set the cycle in motion.
In the past decade, there has been growing recognition of an association between Mycobacterium avium complex (MAC) infection and bronchiectasis.4 Patients with MAC are typically thin, older, nonsmoking women. In these patients, bronchiectasis tends to run a chronic, indolent course with recurrences and relapses despite treatment.
Patients with hypogammaglobulinemia are at elevated risk for bronchiectasis. Causes include congenital syndromes, common variable immunodeficiency, HIV/AIDS, and some malignancies. It is especially important to recognize hypogammaglobulinemia since immunoglobulin replacement has been shown to reduce the number of pulmonary infections and may prevent further airway destruction. Bronchiectasis is also a frequent complication of inflammatory autoimmune diseases, such as rheumatoid arthritis and inflammatory bowel disease.1, 5
A symptom constellation
While cough and chronic sputum production are the cardinal symptoms of bronchiectasis, varying degrees of hemoptysis are also seen in about a third of all patients. Although hemoptysis is usually mild, expectoration of massive amounts of blood leading to airway compromise occasionally occurs. Dyspnea and wheezing are quite common. Pleuritic chest pain occurs in up to half of all patients and is a sign of distended airways or inflammation adjacent to the pleural surface. Physical exam findings may include coarse crackles and rhonchi.
It can be difficult to differentiate between bronchiectasis and other respiratory diseases like asthma and chronic obstructive pulmonary disease. The presence of large amounts of purulent sputum should always raise suspicion for bronchiectasis. This symptom—especially in the presence of comorbidities known to be associated with bronchiectasis—should certainly prompt a diagnostic evaluation.
In the majority of patients with symptomatic bronchiectasis, chest x-rays are abnormal; the findings, however, tend to be relatively nonspecific. They include irregular opacities, linear or platelike atelectasis, and ringlike shadows or “tram lines,” which are linear shadows caused by thickened airways.
Making the diagnosis
When assessing patients with suspected or proven bronchiectasis, be sure to consider possible underlying factors. For example, a history of infertility can lead to a diagnosis of ciliary dysfunction. Coexistent paranasal sinus disease can be a clue to the presence of a systemic cause, such as immunoglobulin deficiency or a cystic fibrosis (CF) variant. Many CF mutations lead to disease that presents in adulthood and is milder than classic CF.
Prior to the widespread availability of CT, bronchography was considered the gold standard when it came to diagnosing and assessing the severity of bronchiectasis.
These days, bronchography has been all but replaced by CT because the latter is both highly accurate and noninvasive. The single best way to identify bronchiectasis on CT is finding a bronchus larger than its accompanying pulmonary artery at any given level.6 This gives rise to the classic “signet ring” sign (Figure 1). Other useful signs include failure of a bronchus to taper while progressing toward the periphery of the lung, and visualization of airways in the extreme lung periphery (Figure 2). Additionally, check for bronchial-wall thickening, mucus impaction, and focal air trapping.
Bronchial hyperresponsiveness and airflow obstruction are common findings in bronchiectasis, and spirometry is recommended as part of a basic workup. Sputum cultures may be helpful in guiding appropriate antimicrobial treatment, ruling out TB and identifying non-TB mycobacteria. When the clinical presentation is suggestive, helpful serologic investigations may include serum immunoglobulin (Ig) G, IgM, and IgA levels; rheumatoid factor; IgE and aspergillus precipitins; and a1-antitrypsin level.
Mucosal biopsies for detection of ciliary dyskinesia and sweat-chloride testing for CF may also be indicated occasionally. Finally, flexible bronchoscopy may be useful in confirming an endobronchial obstruction leading to localized bronchiectasis as well as in collecting biopsy and culture specimens.
Usually incurable—but treatable Since bronchiectasis is generally incurable, management goals usually include improving patients' quality of life by minimizing daily symptoms and preventing acute complications. The rare exception is the severely symptomatic patient with focal bronchiectasis and little comorbidity. In such a patient, surgical resection of the involved portion of lung can be curative.
When considering bronchiectasis management, keep in mind that it is a heterogeneous disease, both in terms of cause and severity. While some patients have severe symptoms with respiratory insufficiency, daily production of large amounts of sputum, and frequent exacerbations, others have only a mild cough with rare exacerbations. Thus, the intensity of treatment will vary greatly from patient to patient. Frequently, referral to a pulmonary specialist is indicated (Table 2).
For most patients, attention to bronchopulmonary hygiene is a cornerstone of therapy. Effective mucus removal is important for improving the patient's quality of life and may also help lessen the inflammatory “driver” of the vicious cycle of bronchial destruction.
In the past, mucus removal was accomplished with postural drainage and percussion, but this is time-consuming and requires a willing and able partner. Currently, several mechanical modalities are available. These include mechanical vibrators and high-frequency chest-wall oscillation with the Vest Airway Clearance System (a device worn by the patient that inflates and deflates rapidly, simulating the action of percussion). Others, such as the Flutter device and the Acapella, are handheld devices that the patient exhales into, creating intermittent positive pressure.
Before devising a treatment plan, consider disease severity, patient preference, and the patient's ability to use a particular device. All patients at the University of Connecticut's Center for Bronchiectasis Care meet with a respiratory therapist who helps determine an optimal bronchial-hygiene regimen.
Since virtually all patients with bronchiectasis are colonized with pathogenic bacteria, antibiotics are an important component of care. Contrary to the usual practice in chronic bronchitis, sputum cultures should be a routine component of bronchiectasis management, since the spectrum of pathogenic organisms is broader and antibiotic resistance is more frequent with this disease.
Although most patients don't need chronic antibiotic treatment, an occasional patient who has frequent exacerbations may do better with either chronic suppressive therapy or a scheduled course of antibiotics each month. Of course, chronic antibiotic therapy raises the risk of resistant strains, so this treatment has its risks. Inhaled tobramycin has been used in some patients who are severely symptomatic due to chronic Pseudomonas infection, and a number have reported improvements in their quality of life.7
Some patients, however, are intolerant of this therapy because of bronchospasm. There have also been reports of slightly improved pulmonary function and cough in patients with long-term Pseudomonas infection who have received chronic oral macrolide therapy. Since macrolides are not effective against Pseudomonas in vitro, this improvement may be due to an immunomodulatory effect of macrolides or an effect on Pseudomonas that is not detected by ordinary in vitro sensitivity testing.
Several studies have suggested that inhalation of hypertonic substances, such as mannitol and hypertonic saline, can improve secretion clearance and ease symptoms in patients with bronchiectasis. Presumably, they do so by increasing water diffusion into the airway, which decreases the viscosity of mucosal secretions.
Patients with severe bronchiectasis usually develop wheezing and bronchospasm. Such individuals should generally be kept on a regimen that includes inhaled corticosteroids and beta-agonist bronchodilators. In randomized trials, inhaled corticosteroids have been shown to improve indices of inflammation and sputum production. Although there is limited evidence proving the benefit of bronchodilators, there is no doubt that many patients with bronchiectasis develop bronchial hyperresponsiveness, which does respond to bronchodilators.
If complications develop
The most common complication of bronchiectasis is acute exacerbation, which is characterized by increased sputum volume and purulence, often with wheezing, fever, and pleuritic chest pain. In fact, it can be difficult to make a distinction between an exacerbation and pneumonia (although it is usually not important to do so).
Treat exacerbations promptly with appropriate antibiotics to minimize duration and severity. In most patients, outpatient treatment with oral antibiotics is adequate. Because many patients harbor multiresistant organisms, sputum culture and sensitivity testing are often indicated. When this approach is taken, antibiotics should be started as soon as the sample is produced, based on the patient's prior culture results and, if quickly available, the Gram's stain results.
In patients without prior Pseudomonas infection, advanced macrolides, amoxicillin-clavulanic acid, second- and third-generation oral cephalosporins, or fluoroquinolones are all appropriate choices for initial empiric coverage. For patients with a suspected Pseudomonas-induced exacerbation, anti-pseudomonal fluoroquinolones, such as ciprofloxacin and levofloxacin, provide the only effective oral therapy, although the chances of resistance are high when there has been recent fluoroquinolone exposure. If there is evidence of bronchospasm, consider a brief course of oral steroids and provide bronchodilators to patients who are not already using them.
Hemoptysis is another complication of bronchiectasis. This is caused by the development of exuberant collateral circulation to the airways via bronchial arteries as a consequence of chronic inflammation. If the patient has never had hemoptysis before, most pulmonologists will perform bronchoscopy to eliminate the possibility of a different etiology, such as lung cancer. In most patients, hemoptysis is neither persistent nor severe, except in the setting of exacerbations. When severe hemoptysis cannot be controlled with antibiotics and cough suppression, one option is bronchial artery embolization, which is approximately 90% effective in controlling acute bleeding.8
Dr. Metersky is professor of clinical medicine and director of the Center for Bronchiectasis Care at the University of Connecticut School of Medicine in Farmington. Dr. Uzunpinar is a fellow in pulmonary and critical care medicine also at the University of Connecticut School of Medicine in Farmington. Dr. Metersky has served on an advisory board/speaker's bureau for the following pharmaceutical companies: Aventis, Bayer, Ortho, Oscient, and Pfizer. Dr. Uzunpinar reports no conflict of interest.
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