The Centers for Disease Control and Prevention (CDC) assembled a panel of national health experts, including physicians with expertise in internal, family, emergency and infectious disease medicine to develop evidence-based guidelines for evaluating and treating adults with acute respiratory disease. The goal of the guidelines, which were compiled by the CDC and other members of the panel, is to provide physicians with practical strategies for limiting antibiotic use to patients who are most likely to benefit. The complete treatment guidelines were published in the March 20, 2001 issue of Annals of Internal Medicine, and they can be viewed online athttp://www.annals.org/issues/v134n6/full/200103200-00013.html.

The following information focuses on the appropriate use of antibiotics for treatment of uncomplicated acute bronchitis:

Acute bronchitis is a clinical diagnosis designating an acute respiratory tract infection in which cough, with or without phlegm, is a predominant feature. For a cough illness lasting less than three weeks, previously undiagnosed asthma and pneumonia should be considered. The primary objective should be to rule out pneumonia, because it is the third most common cause of acute cough illness and potentially the most serious. About 5 percent of adults in the United States self-report an episode of acute bronchitis each year, and 90 percent of these persons seek medical attention.

Diagnosis

In healthy, nonelderly adults, the absence of vital sign abnormalities (heart rate of at least 100 beats per minute, respiratory rate of at least 24 breaths per minute or oral temperature of 38°C [100.4°F] or higher) and asymmetrical lung sounds reduces the likelihood of pneumonia enough that further diagnostic testing is usually unnecessary. In patients with a cough lasting more than three weeks, chest radiography is warranted in the absence of other known causes. Absent from the rules is the presence of purulent sputum. Purulence primarily occurs when inflammatory cells or sloughed mucosal epithelial cells are present, and it can result from viral or bacterial infection. Respiratory viruses, particularly influenza, appear to cause the majority of uncomplicated acute bronchitis cases.

Unless bacterial superinfection (pneumonia with an infiltrate on chest radiography) is present, antibiotic treatment does not affect the clinical course of viral respiratory infection. To date, only Bordetella pertussis, Mycoplasma pneumoniae and Chlamydia pneumoniae have been established as nonviral causes of uncomplicated acute bronchitis in adults.

Treatment

Routine antibiotic treatment of acute bronchitis does not have a consistent impact on duration or severity of illness or on potential complications, such as development of pneumonia. According to the panel, three meta-analyses reported no impact of antibiotic treatment on illness duration, activity limitation or work loss, concluding that routine antibiotic treatment of adults with acute bronchitis is not justified, regardless of the duration of cough.

In the unusual circumstance of pertussis, diagnostic tests should be performed and antibiotic treatment initiated. Physicians should limit suspicion and treatment of adult pertussis to patients with a high probability of exposure, usually occurring during an outbreak. Antibiotics are primarily recommended to decrease shedding of the pathogen and the spread of the disease because antimicrobial therapy does not appear to resolve symptoms if it is initiated seven to 10 days after the onset of illness.

Physicians caring for patients with uncomplicated acute bronchitis should discuss the lack of benefit of antibiotic treatment and stop using prescriptions as standard practice. Evidence reviewed by the panel indicates that patient satisfaction with the office visit does not depend on receipt of an antibiotic, but instead is most dependent on the patient-physician communication. The physician should provide realistic expectations for the duration of cough (10 to 14 days after office visit) and refer to the cough illness as a chest cold rather than bronchitis. It may also help to personalize the risk of unnecessary antibiotic use. Let patients know that previous antibiotic use increases their likelihood of carriage of and infection with antibiotic-resistant bacteria, that antibiotics commonly have side effects and that rare but serious adverse reactions such as anaphylaxis may occur.

Because influenza is the most common isolated pathogen with acute bronchitis, the recent advances in influenza therapy could be discussed. Patients and physicians will need to weigh the high cost of the newer drugs and the possibility of the emergence of viral resistance against the degree to which the duration of symptoms and illness is shortened. All influenza drugs appear to have the same impact of about one less day of illness and about one-half day quicker return to normal activities. For the antiviral agents to be effective, they must be initiated within 48 hours of symptom onset.

Recommendations

These guidelines do not apply to the elderly or those with comorbid conditions such as chronic obstructive pulmonary disease, congestive heart failure or immuno-suppression. Specific patient and epidemiologic circumstances should be taken into account before these recommendations are applied.

• The evaluation of adults with an acute cough illness or a presumptive diagnosis of uncomplicated acute bronchitis should focus on clinically ruling out serious illness, particularly pneumonia.

• Routine antibiotic treatment of uncomplicated acute bronchitis is not recommended, regardless of the duration of cough. Most of the time, acute bronchitis is the result of a viral illness that is self-limited, and will improve on its own. Even though relief of symptoms will not shorten the duration of illness, patients can benefit from analgesics, antipyretics, beta-agonist inhalers, antitussives or vaporizers.