PHILADELPHIA—To help quell the antibiotic-resistance problem, the American College of Physicians–American Society of Internal Medicine (ACP–ASIM) has created guidelines for the management of upper respiratory tract infections (URIs). And the College wants to drive home this message: Antibiotics are usually unnecessary for URIs in otherwise healthy adults.

“Research has shown that most of these infections are viral,” explained Vincenza Snow, MD, a principal author of the guidelines and a Senior Medical Associate at the ACP–ASIM. Nevertheless, more than 75% of antibiotic prescriptions in the United States are for URIs, she told RESPIRATORY REVIEWS. “This sort of antibiotic overuse has been linked to the precipitous rise in antibiotic resistance over the past 10 years,” Dr. Snow stressed.

THE TARGET: PRIMARY CARE PHYSICIANS

The guidelines target primary care physicians (ie, those in family, internal, or emergency medicine), as well as subspecialists who provide primary care. “They apply mainly to adult outpatients who are healthy, not to those with immunosuppression or serious chronic conditions like cardiac or pulmonary disease,” Dr. Snow said. They may also be suitable for some residents of long-term-care facilities.

The guidelines present principles of appropriate antibiotic use for nonspecific URIs, such as the common cold, as well as for acute sinusitis, pharyngitis, and bronchitis.[1-4] The principles are based on corresponding background papers created by a panel of physicians from relevant specialties and endorsed by the Centers for Disease Control and Prevention, the American Academy of Family Physicians, and the Infectious Diseases Society of America.[5-8]

“We could reduce antibiotic use tremendously by following these principles,” asserted Ralph Gonzales, MD, coordinator of the background papers and an Assistant Professor of Medicine at the University of Colorado Health Sciences Center in Denver. The principles are heavily evidence-based, and randomized, placebo-controlled clinical trials are often available to support them, he told RESPIRATORY REVIEWS.

APPROPRIATE ANTIBIOTIC USE

Nonspecific URI. For all URIs, appropriate antibiotic use begins with proper diagnosis. According to the guidelines, physicians should use a diagnosis of nonspecific URI to denote an acute infection in which sinus, pharyngeal, and lower airway symptoms are not prominent (although they may be present).

Influenza or parainfluenza is most likely the cause of nonspecific URI when symptoms are severe and accompanied by muscle aches and fatigue; rhinovirus should be suspected when symptoms are mild. Adenovirus and respiratory syncytial virus are also important causes.

Antibiotics provided no benefit for nonspecific URI in seven randomized placebo-controlled trials with children and adults and in three trials involving only adults. These drugs should therefore not be used to treat nonspecific URI in previously healthy adults, the guidelines advise. Uncomplicated cases should resolve spontaneously in one to two weeks, with most patients feeling much better within the first week.

“Physicians often give antibiotics based on the belief that yellow or green secretions from the nose or throat indicates bacterial infection or that treatment will prevent bacterial superinfection,” said Dr. Snow. “We know now that neither is true.” Indeed, purulent sputum production is a normal part of viral infection, and nonspecific URIs are rarely complicated by bacterial infections.

Acute sinusitis. Appropriate antibiotic treatment for acute sinusitis is difficult to provide because viral and bacterial cases are often clinically indistinguishable, and no simple, accurate test is available to aid diagnosis. Sinus radiography is not recommended as a routine part of diagnosis because of its limited ability to detect bacterial cases.

The diagnosis is therefore still clinical and should be based on illness duration. “Acute bacterial sinusitis is uncommon in patients who have symptoms for less than seven days,” said Dr. Gonzales. “By waiting at least that long, we can weed out most of those with uncomplicated viral illness.”

After seven days, the rate of acute bacterial sinusitis is 40% to 50% among patients with maxillary facial or tooth pain or tenderness and/or persistent purulent nasal discharge. The condition is unlikely if none of those symptoms are present no matter how long the patient has been ill.

Because sinusitis typically improves or resolves on its own, the initial management strategy for mild or moderate cases should be to reassure patients that they will get better and to offer analgesics, antipyretics, and decongestants for symptom relief. Antibiotics are usually only indicated if symptoms do not improve after seven days or if they are severe, regardless of duration. The narrow-spectrum antibiotics amoxicillin, doxycycline, and trimethoprim-sulfamethoxazole are reasonable first-line agents in these types of cases.

Acute pharyngitis. The objective of diagnosis in acute pharyngitis is to determine when group A ß-hemolytic streptococcus (GABHS) is likely to be the cause, as it is in 5% to 15% of cases. “It is the only cause of pharyngitis that responds to antibiotics,” Dr. Gonzales explained.

Because of concerns about its speed and accuracy, throat culture was omitted from the acute pharyngitis guidelines. Instead, they focus on two other diagnostic methods that are faster and reasonably accurate for diagnosing GABHS infection. One is simple clinical assessment for tonsillar exudates, tender anterior cervical lymphadenopathy, absence of cough, and history of fever. The presence of at least three of these four criteria is about 75% sensitive and specific for acute GABHS pharyngitis.

The second method is to use a rapid antigen test. This technique has a reported sensitivity for acute GABHS pharyngitis of 58% to 96% and a specificity of 63% to 100%. The guidelines suggest that best results with the rapid antigen test can be obtained if it is administered only to patients with at least an intermediate probability of having GABHS pharyngitis, as indicated by the presence of two or three key criteria.

Supportive care with systemic and topical analgesics, antipyretics, and gargles is recommended in all cases of acute pharyngitis. However, antibiotic therapy should be limited to the few patients who meet the diagnostic criteria for GABHS-related illness.

The preferred agent is penicillin (or erythromycin in the event of penicillin allergy); therapy must start within 48 to 72 hours of symptom onset to be effective. It typically shortens symptom duration by one to two days and decreases the risk of peritonsillar abscess and other complications, the occurrences of which are rare.

Acute bronchitis. Ruling out pneumonia should be the focus of assessment for acute cough illness or a presumptive diagnosis of uncomplicated acute bronchitis. Pneumonia is a common—and potentially the most serious—cause of acute cough illness, the guidelines explain.

In otherwise healthy adults, pneumonia is unlikely in the absence of vital sign abnormalities or asymmetrical lung sounds. Further diagnostic testing is therefore usually not indicated in these patients. Chest radiography for pneumonia is warranted in those with a cough lasting three weeks or more, however, if there is no other known cause for their symptoms.

Influenza A and B, parainfluenza 3, and respiratory syncytial virus are the pathogens most often associated with acute bronchitis. Routine antibiotic therapy is not recommended regardless of the duration of cough.

Analgesics, antipyretics, inhaled ß-agonists, antitussives, and/or vaporizers should instead be prescribed for symptom relief. If influenza has been identified as the cause of acute bronchitis, anti-influenza medications, such as the new neuraminidase inhibitors, may also be beneficial when started within 48 hours of symptom onset.

Antibiotics are only recommended in the unlikely event of acute bronchitis due to pertussis. The main goal in these cases is to prevent the spread of pertussis by keeping it from shedding. Physicians should limit antibiotic therapy to adults with a high probability of pertussis exposure, such as those involved in a documented outbreak, since pertussis is impossible to distinguish clinically in adults with previous immunity.

GETTING THE MESSAGE TO PATIENTS

Following the guidelines is likely to be easier if patients are informed about the need to curb antibiotic use. Physicians have often failed to do this in the past because they assume that patients with URIs expect antibiotics and do not wish to hear otherwise.

However, most of these patients are likely to understand the reasons for withholding antibiotics if physicians would just take the time to clearly explain them, Dr. Snow maintained. “We created the expectation for antibiotics in our patients, so we will have to reeducate them about antibiotic use,“ she concluded.

—Timothy Begany

The American College of Physicians–American Society of Internal Medicine (ACP–ASIM) has developed a patient education brochure on antibiotic resistance. It is available by calling (800) 523-1546, extension 2600, or by download at the ACP–ASIM Web site at www.doctorsforadults.com.

References
1. Snow V, Mottur-Pilson C, Gonzales R. Principles of appropriate antibiotic use for treatment of nonspecific upper respiratory tract infections in adults. Ann Intern Med. 2001;134:487-489.