John M. Hickner

Principles of Appropriate Antibiotic Use for Acute Pharyngitis in Adults: Background

1.0 Background Sore throat is one of the most common chief complaints of adults treated in an outpatient setting. Although its differential diagnosis is large and includes many other causes that are important to recognize (Table), the vast majority of immunocompetent adults presenting with sore throat have acute infectious pharyngitis. Most of the widespread antibiotic use in such patients is based on an effort to treat bacterial (particularly streptococcal) pharyngitis. Recognition and specific treatment of some of these other sore throat entities are important but are beyond the scope of this paper, which addresses the treatment of nongonococcal, nondiphtherial acute pharyngitis in healthy adults. Table. Differential Diagnosis of Sore Throat in the Immunocompetent Adult 1.1 Acute pharyngitis accounts for 1% to 2% of all visits to outpatient departments, physician offices, and emergency departments (1). A wide range of infectious agents, most commonly viruses, cause acute pharyngitis. Approximately 5% to 15% of cases in adults are caused by group A -hemolytic streptococcus (GABHS) (2-7). In some patients, it can be important to identify an infectious cause other than GABHS (for example, gonococcal pharyngitis, EpsteinBarr virus, and acute HIV infection), but in the vast majority of cases, acute pharyngitis in an otherwise healthy adult is self-limited and rarely produces significant sequelae. 1.2 Antibiotics are prescribed to a substantial majority (approximately 75%) of adult patients with acute pharyngitis (8). Physicians report that they prescribe unwarranted antibiotics because they believe that patients expect them, that patients will reconsult if antibiotics are not prescribed, that patients will be unsatisfied without a prescription, and that it is quicker to write a prescription than to explain why a prescription is not indicated (9-11). However, physicians are not very good at predicting which patients expect antibiotics (11, 12), and patient satisfaction depends less on whether an antibiotic is prescribed, or even whether preconsultation expectations are met, than on whether the physician shows concern and provides reassurance (9, 11-15). Delaying antibiotic prescriptions does not increase the chance that patients will return in the next few days for reconsultation. Prescribing antibiotics medicalizes the illness, and one study found increased likelihood that patients would return for the next similar illness (13, 15, 16). The inappropriate use of antibiotics can have significant negative consequences both to individual patients and to public health. Goals This paper examines the available evidence regarding the diagnosis and treatment of acute GABHS pharyngitis in adult patients. It makes recommendations that balance concerns about the potential consequences of untreated GABHS and the goal of decreasing inappropriate antibiotic prescriptions. It discusses pharyngitis in adults (patients 18 years of age), a population in which GABHS accounts for only approximately 5% to 15% of cases (2-7) and in which such complications as acute rheumatic fever are much less common. These guidelines do not apply to patients with a history of rheumatic fever, valvular heart disease, immunosuppression, or recurrent or chronic pharyngitis (symptoms > 7 days), or to patients whose sore throats have a cause other than acute infectious pharyngitis. They are not intended to apply during a known epidemic of acute rheumatic fever or streptococcal pharyngitis or in nonindustrialized countries in which the endemic rate of acute rheumatic fever is much higher than in the United States. Clinicians should always consider the epidemiologic circumstances when applying these recommendations in practice. Furthermore, these principles are not intended to comment on or contradict previous practice guidelines from other organizations (17, 18), which are primarily directed at sore throat evaluation in children. 2.0 Methods We conducted a systematic review of the literature from 1950 to 2000 for these evidence-based management principles. We identified all randomized, controlled trials or meta-analyses of randomized, controlled trials that contained clear definitions of criteria for inclusion, diagnosis, and outcomes, as well as studies evaluating diagnostic strategies for GABHS pharyngitis. We searched MEDLINE and the Cochrane Library, and we also searched the references of the inception articles to identify other studies. Our search strategy sought English-language articles and used the keywords sore throat, group A streptococcus, pharyngitis, tonsillitis, streptococcal pharyngitis, throat culture, and strep. Many of the identified articles had easily recognizable methodologic flaws (for example, use of convenience samples, exclusion of patients without a throat culture or those without a positive throat culture, and lack of an appropriate or clearly identified criterion standard), and we considered these limitations when evaluating the evidence and making our recommendations. Furthermore, the efficacy reported in the clinical trials may have been affected in part by repeated clinic visits, repeated cultures, and checks of patient adherence to pill ingestion, all of which would result in overestimation of the effect size of treatment. We did not mathematically summarize the various trials because of the variable quality of the cited evidence. 3.0 Evidence for Antibiotic Treatment of Pharyngitis Caused by GABHS Pharyngitis caused by GABHS is predominantly a disease of children 5 to 15 years of age. It has a prevalence of approximately 30% in pediatric pharyngitis but only 5% to 15% in adult pharyngitis in nonepidemic conditions (2-7, 19, 20). Physicians may consider prescribing antibiotics for streptococcal pharyngitis to prevent rheumatic fever, prevent acute glomerulonephritis, prevent suppurative complications, decrease contagion, and relieve symptoms. 3.1 Acute Rheumatic Fever Early randomized trials demonstrated that penicillin treatment of streptococcal pharyngitis is effective in preventing acute rheumatic fever (21-23) (relative risk, 0.28 [24]). This translated into a number needed to treat for benefit (NNTB) of approximately 63 to prevent one case of acute rheumatic fever in the samples studied. These early trials were usually performed in populations with a much higher incidence of acute rheumatic fever in both the treated and control groups than is present today. The reported incidence per population was approximately 60 times greater in 1965 than in 1994 (the last year for which the Centers for Disease Control and Prevention reported statistics); therefore, the NNTB today is undoubtedly much higher, in the range of approximately 3000 to 4000 (25-27). Carditis is the most serious complication associated with acute rheumatic fever. In recent outbreaks of acute rheumatic fever, carditis was seen in 50% to 91% of pediatric cases (28-31). These data probably reflect diagnosis of subclinical cases by echocardiography. Carditis occurred in approximately one third of adult cases of acute rheumatic fever (32, 33). The most important consequence of carditis, permanent valvular dysfunction, is most common after clinically severe carditis (28). Given that acute rheumatic fever is rare in adults, that carditis is not a common feature of adult cases of acute rheumatic fever, and that most cases of carditis in adults are mild or asymptomatic, the likelihood of permanent cardiac dysfunction seems to be very small. Thus, the NNTB to prevent a single case of clinically significant carditis is substantially greater than the NNTB to prevent a single case of acute rheumatic fever. During the 1980s, several outbreaks of acute rheumatic fever occurred, causing concern about reemergence of the disease (29-32, 34, 35). It is important to consider local epidemics. Physicians should be prepared to revise their treatment approaches if evidence suggests an outbreak. 3.2 Acute Glomerulonephritis Although poststreptococcal acute glomerulonephritis occurs, it is extremely rare, even in the absence of antibiotic treatment (36-41). Furthermore, no evidence shows that antibiotic therapy for pharyngitis decreases the incidence of this complication (36-41). 3.3 Peritonsillar Abscess The incidence of suppurative complications, regardless of treatment with antibiotics, is also low (42-45). A review of randomized trials from the 1950s and 1960s indicates that antibiotics decrease the incidence of peritonsillar abscess (quinsy) complicating streptococcal pharyngitis (24), with a best estimate for NNTB of 27. Modern clinical trials (44, 45) provide some evidence that targeting antibiotics to a subset of patients with higher clinical likelihood of GABHS may prevent peritonsillar abscess. However, in another recent review of GABHS pharyngitis in practice, Little and Williamson (46) reported that the risk for peritonsillar abscess was not reduced because many patients did not present for care until after the complication had developed (46). A recent retrospective study of more than 30 000 patients confirms these findings (47). Among patients who developed suppurative complications, 31 of 71 (44%) had them at first presentation (47). Of the other 56% who presented with pharyngitis before subsequent development of peritonsillar abscess, only approximately 25% showed GABHS on culture or rapid antigen test, and most (67%) had been treated with antibiotics that effectively eradicated GABHS. 3.4 Prevention of Spread of Disease Streptococcal infection often occurs in epidemics, and contagion is a problem in areas of overcrowding or close contact. Although treatment must continue for 10 days, 24 hours of antibiotic therapy greatly reduces the recovery of GABHS from pharyngeal cultures (41, 48-50). While antibiotics are recommended as a means of reducing spread in schools and other closed settings (20), the impact of treatment on disease spread in noninstitutionalized adult po

Principles of Appropriate Antibiotic Use for Treatment of acute respiratory Tract Infections in adults: Background, specific aims, and methods

Background The Need To Improve Antibiotic Prescription for Acute Respiratory Infections 1. The epidemic increase in antibiotic-resistant Streptococcus pneumoniae is an ambulatory care problem. Excessive use of antibiotics in ambulatory practice has contributed to the emergence and spread of antibiotic-resistant bacteria in the community (1-4). Penicillin resistance in S. pneumoniae has increased in an epidemic manner in the past 10 years (5, 6). Resistance to macrolides, doxycycline, trimethoprimsulfamethoxazole, and second- and third-generation cephalosporins has also increased. Special attention to antibiotic-resistance profiles of S. pneumoniae is warranted, since this pathogen is the leading cause of community-acquired bacterial pneumonia, bacterial meningitis, bacterial sinusitis, and otitis media in the United States (7). 2. Previous antibiotic use is an important risk factor for carriage of and infection with antibiotic-resistant Streptococcus pneumoniae. The major risk factors for carriage of and infection with antibiotic-resistant S. pneumoniae are geographic location, recent exposure to antibiotics, and exposure to young children. Carriage of S. pneumoniae (and antibiotic-resistant S. pneumoniae) primarily occurs in the nasopharynx and oropharynx of susceptible hosts (8, 9). Factors contributing to the spread of S. pneumoniae (such as close contact and viral respiratory infections) are also associated with the spread of antibiotic-resistant S. pneumoniae (10-12). For example, carriage and transmission of antibiotic-resistant S. pneumoniae are greatest during winter months and in environments that facilitate the transmission of respiratory secretions (8). The prevalence of carriage of S. pneumoniae and antibiotic-resistant S. pneumoniae appears to be greatest in young children; up to one third of children who visit health clinics are reported to be nasopharyngeal carriers of antibiotic-resistant S. pneumoniae (13-15). The prevalence of S. pneumoniae colonization in the upper airways in adults is about 5%; this value increases if children are present in the household (10). Although the risks for transmission of antibiotic-resistant S. pneumoniae mirror those for S. pneumoniae, numerous retrospective and prospective carriage studies have also identified previous antibiotic use, especially for a prolonged period (for example, as prophylaxis against recurrent acute otitis media), to be the most significant risk factor for carriage and subsequent spread of antibiotic-resistant S. pneumoniae (14-18). The risk for carriage of antibiotic-resistant S. pneumoniae is two to nine times greater in persons who have recently used antibiotics. A precipitously rapid increase in antibiotic resistance has also been observed for strains of S. pneumoniae in blood, cerebrospinal fluid, and joint fluid in the United States since 1986, when invasive antibiotic-resistant S. pneumoniae isolates were rare or absent (5). Like carriage of antibiotic-resistant S. pneumoniae, invasive infection with antibiotic-resistant S. pneumoniae is associated with previous antibiotic use (6, 19-22). When invasive infection with antibiotic-resistant S. pneumoniae occurs, antibiotics with poor central nervous system penetration and bacteriostatic (instead of bactericidal) properties must sometimes be used. Treatment failures have been reported in patients with pneumococcal meningitis after therapy with penicillin, chloramphenicol, clarithromycin, ceftriaxone, and cefotaxime (12, 23-26). The management of outpatient bacterial infections, such as acute otitis media, becomes substantially more difficult because of high rates of antibiotic-resistant S. pneumoniae in children with such infections (27, 28). However, few studies have quantified the clinical impact of antibiotic-resistant S. pneumoniae on morbidity, mortality, and health care costs in children or adults. In a study of hospitalized patients with severe pneumococcal pneumonia in Spain, where a high prevalence of antibiotic-resistant S. pneumoniae preceded the current increase in the United States, no association was seen between antibiotic resistance and mortality (29). However, most patients had intermediate-level penicillin resistance; in such patients, serum and lung interstitium concentrations of antibiotic are sufficiently high to overcome resistance. A recent study of U.S. adults hospitalized with community-acquired pneumonia due to S. pneumoniae found that mortality was significantly associated with high-level antibiotic-resistant S. pneumoniae (minimum inhibitory concentration 4 g/mL), after exclusion of deaths that occurred within the first 2 to 4 days of hospitalization (30). Exclusion of early deaths is justified, since antibiotic therapy has not been shown to affect early mortality in adults with antibiotic-susceptible pneumococcal disease (31). Because of the current increase in antibiotic resistance in community bacterial pathogens, many experts are predicting an impending postantibiotic era (2-4). 3. Most antibiotic prescriptions in the ambulatory setting are for acute respiratory infections. Intervention strategies aimed at reducing community use of antibiotics must address the management of acute respiratory infections. These illnesses are the most frequent reasons for seeking medical attention in the United States, and they are associated with up to 75% of total antibiotic prescriptions each year (32). Transmission of S. pneumoniae is enhanced during viral acute respiratory infection through increased respiratory and nasal secretions (10). As a result, antibiotic treatment of viral acute respiratory infections is particularly problematic, since it may selectively promote the acquisition and spread of antibiotic-resistant bacteria by patients. Specific acute respiratory infections that must be targeted for reducing unnecessary antibiotic use in adults are uncomplicated acute bronchitis (not including acute exacerbations of chronic bronchitis), acute sinusitis, pharyngitis, and nonspecific upper respiratory tract infection (including the common cold). These diagnoses are usually made in the presence of a clinical syndrome with a predominant clinical feature, so that prominent acute cough is taken to mean acute bronchitis, prominent nasal and sinus symptoms are thought to signify sinusitis, and prominent acute sore throat is considered pharyngitis. Acute respiratory symptoms in the absence of a predominant symptom are typically diagnosed as upper respiratory tract infection. Each of these syndromes can be caused by a multitude of different viruses and, on occasion, bacteria. The degree of excess prescription of antibiotics varies for each diagnosis. Antibiotic treatment of a cold, an upper respiratory tract infection, or acute bronchitis is almost always inappropriate because the vast majority of these syndromes have a nonbacterial cause. Antibiotic treatment of sinusitis and pharyngitis is sometimes justified but should be limited to appropriate subsets of patients. Potential Benefit and Harm of Adherence to Principles of Appropriate Antibiotic Prescription Potential Benefits of Indiscriminant Antibiotic Prescription Some clinicians may prescribe antibiotics because they believe that a very small fraction of patients might benefit or they hope to prevent the remote case of a bad outcome (and a potential lawsuit). A theoretical clinical benefit of treating viral respiratory tract infections with antibiotics cannot be excluded. A truism for all clinical trials performed in medicine is that a benefit of treatment cannot be excluded for outcomes that occur less frequently than the sample size can detect (that is, there will always be specific outcomes that were not or cannot be measured). For example, invasive bacterial disease, such as sepsis or bacterial meningitis, is too rare an event to be evaluated in a randomized, controlled trial with enough power to exclude a potential benefit of antibiotic treatment. The incidence of bacterial meningitis in the United States is about 3 per 100 000 persons in the general population (1995) (33) or about 9 per 100 000 persons with an office visit for an acute respiratory illness (unpublished data based on the National Ambulatory Medical Care Survey, 1997). Indiscriminant use of antibiotics may also in theory prevent complications of other undiagnosed bacterial infections, such as acute rheumatic fever. While these hypothetical benefits are possible, no evidence supports their existence. Potential Harms of Indiscriminant Antibiotic Prescription In contrast to the theoretical clinical benefit of indiscriminant prescription of antibiotics, the potential harm of this practice is well established at the level of the patient and society. At the patient level, risks include allergic reactions (such as urticaria, rash, and anaphylaxis), adverse reactions (such as gastrointestinal discomfort or yeast infections), and drugdrug interactions (such as QT interval prolongation caused by warfarin and oral contraceptives), as well as the increased likelihood that a pneumococcal infection in the ensuing months will be due to an antibiotic-resistant strain. At the societal level, the adverse effects of indiscriminant antibiotic use on rates of antibiotic resistance are well established, and the effects on health care costs (for antibiotics and office visits) are straightforward. Finally, indiscriminant antibiotic use could serve to inappropriately medicalize viral illnesses. This tendency not only usurps the ability of individual persons to care for self-limited illnesses but also carries large associated costs in terms of unnecessary office visits and prescriptions. Potential Benefits of Limiting Indiscriminant Antibiotic Prescription Besides decreasing the risk for the harms noted above, the intended result of efforts to decrease indiscriminant antibiotic use in the ambulatory setting is to reduce (and preferably reverse) the increase in antibiotic-re

Principles of appropriate antibiotic use for acute rhinosinusitis in adults: background.

1.0 The excessive use of antibiotics in ambulatory practice has contributed to the emergence and spread of antibiotic-resistant bacteria (1-2, 4). Antibiotic treatment of common respiratory infections accounts for a large percentage of this excessive use. Rhinosinusitis is one of the 10 most common diagnoses in ambulatory practice and is the cause of an estimated 25 million U.S. physician office visits in 1995 (5). Fourteen percent of Americans claim to have had a previous diagnosis of sinusitis (6), but the term sinusitis typically has a different meaning for patients and for primary care physicians. When patients say I have sinus trouble, they usually describe acute or chronic symptoms, such as headache, facial pain, nasal congestion, or rhinorrhea, each of which may be due to a variety of causes. Primary care physicians tend to think of sinusitis as an acute bacterial infection, for which they prescribe an antibiotic in 85% to 98% of cases (7, 8). According to data from the National Ambulatory Medical Care Survey, sinusitis is the fifth most common diagnosis for which an antibiotic is prescribed (9). However, sinusitis is frequently caused by viral infection and will resolve in most patients without antibiotic treatment. These principles present an argument for a conservative approach to use of antibiotics in patients with sinusitis-like symptoms, consistent with efforts to reduce antibiotic use for respiratory infections in ambulatory patients. Background, rationale, and methods used for development of these principles have been published separately (10). 1.1 The term sinusitis refers to inflammation of the mucosa of the paranasal sinuses, regardless of cause. Because sinusitis is invariably accompanied by inflammation of the contiguous nasal mucosa, rhinosinusitis has become the preferred term. Most cases of rhinosinusitis involve more than one of the paranasal sinuses, most commonly the maxillary and ethmoid sinuses. Isolated infection of a frontal or sphenoid sinus is a rare and potentially dangerous condition, usually caused by bacteria, which presents very differently from the vast majority of cases of rhinosinusitis seen in primary care. Patients with this type of infection seem seriously ill and may show signs of cavernous sinus thrombosis or meningitis. Diagnosis and treatment of isolated frontal and sphenoid sinusitis are beyond the scope of this discussion. For purposes of diagnosis and treatment, rhinosinusitis is classified as acute (symptom duration < 4 weeks), subacute (symptom duration 4 to 12 weeks), and chronic (symptom duration > 12 weeks) (11). Patients may have recurrent acute attacks or acute exacerbations of chronic rhinosinusitis. Chronic and subacute bacterial sinus infections may require surgical consultation and management. Acute rhinosinusitis, however, makes up most cases in ambulatory care, and primary care clinicians treat most of these infections without consultation. These principles are limited to the diagnosis and treatment of acute maxillary and ethmoid rhinosinusitis in immunocompetent adults. 1.2 Acute bacterial rhinosinusitis is usually a secondary infection resulting from sinus ostia obstruction or impairment of mucus clearance mechanisms caused by an acute viral upper respiratory tract infection (12). Streptococcus pneumoniae and Haemophilus influenzae are the bacteria most commonly isolated from infected maxillary sinuses (13). Streptococcus pyogenes, Moraxella catarrhalis, and anaerobic bacteria each account for a small percentage of bacterial sinus infections. Current reviews providing more details of the pathogenesis of acute and chronic sinusitis have recently been published (11, 13). The gold standard for diagnosis of bacterial rhinosinusitis is sinus puncture with aspiration of purulent secretions that yield growth on culture of at least 105 organisms per milliliter of a likely respiratory pathogen (14). However, sinus puncture is an invasive procedure seldom performed in primary care and is usually indicated only in complicated cases, such as those resistant to treatment. Because no simple and accurate office-based tests for acute bacterial rhinosinusitis are available, clinicians rely on clinical findings to make the diagnosis. However, signs and symptoms of acute bacterial rhinosinusitis and of prolonged viral upper respiratory tract infections are extraordinarily similar, making the clinical diagnosis of acute bacterial rhinosinusitis difficult and resulting in frequent misclassification of viral cases. Antibiotics have potential value in treating acute rhinosinusitis only when true bacterial infection is present. Therefore, two issues must be addressed before use of antibiotics is considered for acute rhinosinusitis. First, can one reliably differentiate acute bacterial rhinosinusitis from acute viral rhinosinusitis and, if so, how? Second, are antibiotics effective in treatment of acute bacterial rhinosinusitis and, if so, how effective? Principles Principle 1. Most cases of acute rhinosinusitis diagnosed in ambulatory care are caused by uncomplicated viral upper respiratory tract infections [A]. (Letters in square brackets are evidence ratings. See the background document in this issue [10] for explanation.) 2.0 Causes of acute sinus inflammation include infection, allergy, and local irritants. Cases due to allergy and irritants can usually be distinguished from infection on the basis of a careful history. Symptoms due to allergy and environmental irritants are usually more chronic or recurrent, are infrequently associated with purulent nasal discharge, frequently include itching and sneezing, and are often associated with specific exposures. Adult patients are often accurate in self-diagnosis of allergic rhinitis (15). Infectious causes of acute rhinosinusitis include respiratory viruses, fungi, and bacteria. Fungal infections are rare in immunocompetent hosts. Viruses cause most cases of acute sinus inflammation. Maxillary sinus radiographs of young adults with typical viral upper respiratory tract infections showed mucosal abnormalities in 39% of cases on the seventh day of illness (16), and computed tomographic scans were abnormal in 87% of similar cases (17). These studies show that some degree of sinus mucosa inflammation is very common in viral upper respiratory tract infections. On the basis of epidemiologic estimates, only 0.2% to 2% of viral upper respiratory tract infections in adults are complicated by bacterial rhinosinusitis (18, 19), and approximately 15% of people with symptoms of acute respiratory infection seek medical care (20). Presuming a 2% bacterial rhinosinusitis infection rate, if all patients with bacterial rhinosinusitis were among those seeking care, no more than approximately 13% (0.02/0.15) of patients who presented with symptoms of acute respiratory infection would have bacterial rhinosinusitis. Yet the ratio of cases in which primary care physicians diagnose upper respiratory tract infection and acute rhinosinusitis in adults is approximately 1:1 (7, 8), suggesting that clinicians frequently misclassify viral upper respiratory tract infections as acute bacterial rhinosinusitis. Principle 2. Bacterial and viral rhinosinusitis are difficult to differentiate on clinical grounds [B]. The clinical diagnosis of acute bacterial rhinosinusitis should be reserved for patients with rhinosinusitis symptoms lasting 7 days or more who have maxillary pain or tenderness in the face or teeth (especially when unilateral) and purulent nasal secretions. Patients who have rhinosinusitis symptoms for less than 7 days are unlikely to have bacterial infection. 3.0 Overdiagnosis of acute bacterial rhinosinusitis is not surprising, considering the lack of specific clinical features that distinguish it from nonbacterial upper respiratory tract infections. Relying on overall clinical impression, primary care physicians classifying patients as highly likely to have bacterial rhinosinusitis are correct in approximately 40% to 50% of cases (18-22). Often, patients and physicians believe that an upper respiratory tract infection has gone on for too long and that antibiotic treatment is therefore needed. Gwaltney and colleagues (21) studied the natural history of rhinovirus illness in young adults. Length of illness ranged from 1 to 33 days, and only one fourth of the patients had symptoms lasting longer than 14 days. Most were well or nearly well in 7 to 10 days. However, in clinical trials of diagnosis and treatment of rhinosinusitis, duration of illness alone does not reliably distinguish prolonged viral infection from bacterial rhinosinusitis (Williams J, Hansen JG, Lindbaek M. Personal communication). For example, Lindbaek found that, among patients with sinusitis-like symptoms referred from primary care physicians, 80% of those with computed tomography criteria for bacterial sinusitis (air-fluid level or total opacification) had had symptoms for longer than 7 days, while 70% of those without computed tomography criteria for bacterial rhinosinusitis also had symptoms for more than 7 days. Nonetheless, bacterial rhinosinusitis was seen in only 20% of patients whose symptoms lasted less than 7 days (Lindbaek M. Personal communication). Therefore, duration of symptoms of 7 days or greater is a moderately sensitive but nonspecific predictor of bacterial rhinosinusitis. 3.1 Aside from duration of illness, are any symptoms and signs helpful in distinguishing between bacterial and viral rhinosinusitis? Since 1976, seven investigators have published reports attempting to identify signs and symptoms specific to acute bacterial rhinosinusitis (22-28). All seven studies are limited by use of imperfect diagnostic standards. None used the best criterion for diagnosing bacterial rhinosinusitis, which is aspiration of purulent secretions on sinus puncture that grow at least 105 organisms per milliliter of a likely respiratory pathogen on culture. The findings of

Principles of Appropriate Antibiotic Use for Treatment of Nonspecific Upper Respiratory Tract Infections in Adults: Background

Upper respiratory tract infections (including the common cold) represent an important target for improving appropriate antibiotic use in ambulatory practice. In 1995, upper respiratory tract infection was the most frequent reason for seeking ambulatory care in the United States, resulting in more than 37 million visits to physician practices and emergency departments (1). Antibiotics are frequently prescribed for upper respiratory tract infections. The National Ambulatory Medical Care Survey, which specifically instructs participating physicians and staff on accurate diagnosis-coding procedures, revealed rates of antibiotic prescription for uncomplicated upper respiratory tract infection of 52% (2). Upper respiratory tract infection is the second leading condition for which antibiotics are prescribed each year, and it accounts for 10% of all antibiotics prescribed annually in ambulatory practice (3). The overuse of antibiotics for upper respiratory tract infections has prompted attempts to better understand this practice. Physicians have reported that unrealistic patient expectations, patient pressure to prescribe antibiotics, and insufficient time to educate patients about the ineffectiveness of antibiotics are some of the reasons why antibiotics are prescribed for upper respiratory tract infections (4). However, the clinical presentation of patients also appears to affect the decision to prescribe antibiotics for upper respiratory tract infection. A study that used a standardized symptom and physical examination recording form concluded that clinicians identify and treat with antibiotics a subset of upper respiratory tract infections primarily characterized by the presence of purulent manifestations (5). Purulent or green nasal discharge (reported or observed), production of green phlegm, presence of tonsillar exudate, and current tobacco use were independent predictors of antibiotic treatment of upper respiratory tract infection. In this study, 82% of patients prescribed antibiotics had at least one of these factors, and a significant linear relationship was observed between the number of factors present and the likelihood of antibiotic prescription. These findings are consistent with those of a physician survey in which respondents were more likely to prescribe antibiotics for hypothetical cases of upper respiratory tract infection when purulent nasal discharge was present (6). The goals of this paper are to provide evidence-based recommendations for when to apply the diagnosis of upper respiratory tract infection and when to consider antibiotic treatment of adults with an uncomplicated upper respiratory tract infection. The background to, rationale for, and methods used to develop these principles are published separately (7). 1.0 Principles Principle 1. The diagnosis of upper respiratory tract infection should be used to denote an acute infection that is typically viral in origin and in which sinus, pharyngeal, and lower airway symptoms, although frequently present, are not prominent [B]. (Letters in square brackets are evidence ratings. See the background document in this issue [7] for explanation.) 1.1 Classification of patients with acute respiratory tract infections has traditionally been based on the anatomic localization of the prominent clinical signs and symptoms accompanying the illness (for example, sinusitis, pharyngitis, bronchitis, otitis media, and nasopharyngitis [the common cold]), and the diagnosis of upper respiratory tract infection has been reserved for cases with no prominent localizing features (8). It is very likely that clinicians vary in how they apply this taxonomy, since professional society recommendations for diagnosis of upper respiratory tract infection also vary. The International Classification of Health Problems in Primary Care defines upper respiratory tract infection as acute inflammation of nasal or pharyngeal mucosa in the absence of other specifically defined respiratory infection. Alternatively, the American Thoracic Society (9) and the Medical Research Council (United Kingdom) (10) recommend classification systems that do not include upper respiratory tract infection as an option. For example, the Medical Research Council provides the following options for classifying acute respiratory illnesses: common cold, otitis media, pharyngitis (including tonsillitis), laryngitis, croup, tracheitis, bronchitis, bronchiolitis, pneumonia, and influenza. 1.2 Evans (8) has conducted numerous studies of the microbiology of acute respiratory syndromes. He defines upper respiratory tract infection as an undifferentiated clinical picture whose classification is based largely on the absence [italics added] of predominating features: thus the nose doesnt run enough, the throat is not sore nor red enough, and the cough is not severe nor paroxysmal enough to classify the illness as one of the other respiratory syndromes. With rare exceptions, upper respiratory tract infections have a viral cause (11-13). When symptoms are severe, and particularly when they are accompanied by muscle ache and fatigue, influenza and parainfluenza infections are the most common causes, whereas rhinoviruses predominate when symptoms are mild. Other agents that are important causes of upper respiratory tract infection syndromes in adults include adenovirus and respiratory syncytial virus. 1.3 Most cases of uncomplicated upper respiratory tract infections in adults resolve spontaneously, although a small proportion become complicated by bacterial rhinosinusitis or bacterial pneumonia (particularly in high-risk patients with influenza, such as infants, elderly persons, and chronically ill patients). Symptoms caused by upper respiratory tract infection typically last 1 to 2 weeks, and most patients will feel much better within the first week. Sinusitis usually develops after an upper respiratory tract infection because of obstruction of the sinus ostia, whereas bacterial pneumonia in adults with influenza infection usually results from the effects of influenza on host immunity. Although most patients with the common cold exhibit sinus involvement on computed tomography performed within 2 to 4 days of symptom onset (14), only about 2% of cases of the common cold in adults are complicated by acute bacterial sinusitis (15). Bacterial rhinosinusitis should be suspected when symptoms have lasted at least 7 days and the illness is accompanied by purulent nasal discharge and other localizing features (16). As described below, antibiotic treatment of upper respiratory tract infection has not been shown to alter the rates of these uncommon complications. 2.0 Principle 2. Antibiotic treatment of adults with nonspecific upper respiratory tract infection does not enhance illness resolution and is not recommended [A]. Studies specifically testing the effect of antibiotic treatment on complications of nonspecific upper respiratory tract infections have not been performed in adults. Life-threatening complications are rare. 2.1 Most randomized, placebo-controlled trials of antibiotic therapy for upper respiratory tract infections have been performed in children. A systematic review performed by the Cochrane Collaboration in 1998 evaluated trials in which patients with the diagnosis of upper respiratory tract infection or the common cold were treated with antibiotics or placebo (17). Trials in which 5% or more of participants had group A -hemolytic streptococci on throat swab, those in which bronchitis was diagnosed, those in which patients had purulent sputum or purulent nasal discharge, and those in which symptoms lasted for more than 6 days were excluded. Analysis of seven trials including patients of all ages revealed that antibiotic treatment did not affect resolution of illness (summary odds ratio, 0.95 [95% CI, 0.70 to 1.28]) or loss of work time (measured in only one study). The three trials that enrolled adults only also showed no benefit of treating routine upper respiratory tract infections with antibiotics (Table) (18-20). In an additional randomized, controlled trial that compared penicillin with aspirin, no effect of antibiotic treatment was observed in hospitalized and ambulatory university students with nonspecific upper respiratory tract infection (21). Table. Randomized, Placebo-Controlled Trials of Antibiotic Treatment of Upper Respiratory Tract Infection in Adults 2.2 No published studies have specifically evaluated the effect of antibiotic treatment of upper respiratory tract infections on subsequent complications in adults. Among children, early antibiotic treatment of upper respiratory tract infection does not appear to prevent pneumonia or acute otitis media (22, 23). Systematic reviews by the Cochrane Collaboration report a consistent benefit of nasal decongestants in relieving nasal congestion associated with the common cold and equivocal results of treatment with zinc, echinacea, and humidified air (24-27). Some of the variation in treatment effects of zinc and echinacea on cold symptoms in different trials may be due to variation in doses of active ingredient and formulations. A randomized, placebo-controlled trial of zinc acetate (28), published after the systematic review (25), reported a 3- to 4-day decrease in duration of illness and a decrease in illness severity. Study participants began treatment on the first day of illness onset and ingested an average of 6 lozenges, each containing 12.8 mg of zinc acetate, daily for 4 to 5 days. 3.0 Principle 3. Purulent secretions from the nares or throat (commonly observed in patients with uncomplicated upper respiratory tract infection) predict neither bacterial infection nor benefit from antibiotic treatment [A]. Although physicians often rely on the presence of purulent nasal discharge and purulent sputum to assign more specific diagnoses, such as acute rhinosinusitis or acute bronchitis, in patients with acute respiratory illness, these symptoms are

Principles of Appropriate Antibiotic Use for Treatment of Uncomplicated Acute Bronchitis: Background

The term acute bronchitis usually designates an acute respiratory tract infection in which cough, with or without phlegm, is a predominant feature (1, 2). In the United States, about 5% of adults self-report an episode of acute bronchitis each year, and up to 90% of these persons seek medical attention (3-5). In 1997, adults in the United States made more than 10 million office visits for bronchitis (6). As a result, acute bronchitis consistently ranks among the 10 conditions that account for most ambulatory office visits to U.S. physicians (6-11). Most cases of acute bronchitis occur in otherwise healthy adults, in whom this acute cough illness can be called uncomplicated acute bronchitis; these principles are intended to apply to such patients. The evaluation and management of acute cough illness in patients with underlying chronic obstructive pulmonary disease, congestive heart failure, or immunosuppression must be tailored in light of the patients comorbid condition and is outside the scope of this discussion. The background of, rationale for, and methods used to develop these principles are published separately (12). Principles 1.0 Evaluation of Acute Cough Illness Principle 1. The evaluation of adults with an acute cough illnessor a presumptive diagnosis of uncomplicated acute bronchitis should focus on ruling out serious illness, particularly pneumonia. 1.1 A wide variety of infections and inflammatory disorders can lead to an acute cough illness. The American College of Chest Physicians defines acute cough illness, in contrast to chronic or persistent cough, as lasting less than 3 weeks (13). Acute upper respiratory tract infection accounted for approximately 70% of primary diagnoses in adults presenting for an ambulatory office visit with a chief symptom of cough (14). Asthma and pneumonia were the next most common diagnoses, assigned to 6% and 5% of patients, respectively. The predominance of cough and accompanying clinical features suggestive of an acute upper respiratory tract infection, such as sore throat or rhinorrhea, is usually used to distinguish bronchitis from other acute upper respiratory tract infections (1). As one might expect, cliniciansare inconsistent in assigning each diagnosis (2). For example, some clinicians diagnose acute bronchitis only when productive cough is present; others insist on the presence of purulent sputum. 1.2 Previously undiagnosed asthma is a consideration in patients presenting with an acute cough illness. However, in the setting of acute cough (<2 to 3 weeks duration), the diagnosis of asthma is difficult to establish because many patients with acute bronchitis will have transient bronchial hyperresponsiveness (and abnormal results on spirometry). No guidelines have been established for distinguishing transient from chronic bronchial hyperresponsiveness, and long-term follow-up studies suggest that abnormalities on pulmonary function testing in patients with uncomplicated acute bronchitis typically resolve after 2 to 3 weeks, although they may last as long as 2 months (15-17). The diagnosis of cough-variant asthma, in contrast, is generally reserved for patients with persistent cough (>2 to 3 weeks duration), lack of wheezing, and (usually) normal results on pulmonary function tests (18, 19). Cough-variant asthma should be suspected in adults with persistent cough that worsens at night or after exposure to cold or exercise; the diagnosis relies on improvement of symptoms with bronchodilator treatment or a positive result on a methacholine challenge test. Therefore, in the absence of severe airflow obstruction, it is prudent to limit evaluation for possible chronic asthma or cough-variant asthma to patients with cough illness lasting longer than 3 weeks. 1.3 When evaluating an otherwise healthy adult with uncomplicated acute cough illness, the primary diagnostic objective should be to exclude the presence of pneumonia. Four prospective studies (1984 to 1990) examined the accuracy of patient history and physical examination for diagnosing radiographic pneumonia in adults with acute respiratory illness in outpatient and emergency department settings, and a clinical decision tool to determine the need for radiography was developed (20-23). A subsequent validation study done by an independent group of investigators found that the specificity (about 67%) but not the sensitivity (about 75%) of these prediction rules for detecting radiographic pneumonia exceeded that of physician judgment (specificity, 58%) (24). An evidence- and quality-based review of these studies (25) concluded that the absence of abnormalities in vital signs (heart rate 100 beats/min, respiratory rate 24 breaths/min, or oral temperature 38 C) and chest examination (focal consolidationfor example, rales, egophony, or fremitus) sufficiently reduces the likelihood of pneumonia to the point where further diagnostic testing is usually not necessary [A]. (Letters in square brackets are evidence ratings. See the background document in this issue [12] for explanation.) Notably absent from all of the rules is the presence of purulent sputum. Many patients and physicians seem to believe that purulent sputum signifies that a bacterial infection is present and antibiotic therapy is indicated (26-28). Purulence primarily occurs when inflammatory cells or sloughed mucosal epithelial cells are present, and it can result from either viral or bacterial infection (29, 30). 1.4 Specific patient and epidemiologic circumstances should be taken into account before this recommendation is applied. Although all of the studies on which this recommendation is based included elderly persons and patients with chronic lung disease, subgroup analyses were not performed; a high index of suspicion for pneumonia therefore remains warranted in these patient groups, given the increased likelihood for atypical disease presentation (31, 32). Conversely, even when vital sign abnormalities are detected in the absence of chest auscultatory findings, chest radiography may not be indicated in patients with other clinical features consistent with a viral illness (such as influenza, parainfluenza, or respiratory syncytial virus) or features that are inconsistent with pneumonia (such as streptococcal pharyngitis or chronic sinusitis). Cough lasting longer than 3 weeks exceeds the case definition for acute bronchitis; such patients should be considered to have persistent cough or chronic cough illness. Irwin and colleagues have developed a well-defined approach to the adult with persistent cough (13) [D]. 2.0 Microbiology of Uncomplicated Acute Bronchitis The vast majority of cases ( 90%) of uncomplicated acute bronchitis have a nonbacterial cause. We reviewed the MEDLINE database (1966 to October 1999) by using Medical Subject Headings and keyword searches that included microbiology and bronchitis and analyzed references from review articles and chapters in textbooks on infectious disease to identify studies of the microbiology of acute bronchitis. We excluded studies involving patients with chronic lung disease, malignant conditions, or immunosuppression, as well as those conducted during confirmed outbreaks of a pathogen (for example, a Chlamydia pneumoniae outbreak at a single university). We limited our selection to English-language studies of consecutive, unselected adolescents or adults enrolled in nonreferral, ambulatory settings. In the mid-1980s, it was established that a specific species of C. pneumoniae (TWAR) could cause uncomplicated acute bronchitis. Therefore, estimates of the proportion of cases with a potential bacterial cause are limited to studies published since this discovery (33, 34). 2.1 As in community-acquired pneumonia, microbiological study of uncomplicated acute bronchitis identifies a pathogen in the minority of cases, ranging from 16% to 40% (17, 35-38). This variability is most likely due to the epidemic nature of agents that produce uncomplicated acute bronchitis and limitations in viral and bacterial identification techniques. Noninfectious causes of uncomplicated acute bronchitis, such as occult asthma exacerbation or toxic fume inhalation, should also be considered, although the prevalence of these conditions in adults with acute cough illness has not been well studied. In epidemiologic studies, respiratory viruses, particularly influenza, appear to cause the large majority of cases of uncomplicated acute bronchitis according to culture, antibody serology, or polymerase chain reaction. Specific viruses most frequently associated with acute bronchitis include those that produce primarily lower respiratory tract disease (influenza B, influenza A, parainfluenza 3, and respiratory syncytial virus), as well as viruses that more commonly produce upper respiratory tract symptoms (corona virus, adenovirus, and rhinoviruses). Unless bacterial superinfection is present (defined as pneumonia with an infiltrate on chest radiography), antibiotic treatment does not affect the clinical course of viral respiratory infections. 2.2 To date, only Bordetella pertussis, Mycoplasma pneumoniae, and C. pneumoniae (TWAR) have been established as nonviral causes of uncomplicated acute bronchitis in adults. As a group, these agents are associated with 5% to 10% of all cases of uncomplicated acute bronchitis in adults. They are recovered more frequently (10% to 20% of cases) in studies of adults with chronic or persistent cough (39-41). The diagnoses in these studies are frequently based on serologic conversion, an event that can also occur in asymptomatic persons and may not be related to the clinical illness in question. More recent studies using polymerase chain reaction have reported similar frequencies of recovery of these agents in adults with acute bronchitis. No evidence indicates that Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis produces acute bronchitis in adults without underlying lung disea

Principles of appropriate antibiotic use for acute sinusitis in adults.

In this guideline, we will present the supporting evidence for and make specific recommendations on how clinicians evaluating acute sinusitis can differentiate bacterial causes from viral causes and how they can determine when the use of antibiotics is beneficial. The numbers in square brackets are cross-references to the numbered sections in the accompanying background paper, Principles of Appropriate Antibiotic Use for Acute Rhinosinusitis in Adults: Background, which is part 2 of this guideline (see pages 498-505). Acute Sinusitis The term sinusitis refers to inflammation of the mucosa of the paranasal sinuses. Because sinusitis is invariably accompanied by inflammation of the contiguous nasal mucosa, rhinosinusitis has become the preferred term. Rhinosinusitis is one of the 10 most common diagnoses in ambulatory practice and is the fifth most common diagnosis for which an antibiotic is prescribed. Primary care physicians tend to think of sinusitis as an acute bacterial infection and prescribe an antibiotic in 85% to 98% of cases. However, sinusitis is frequently caused by viral infection. It will often resolve in most patients without antibiotic treatment, even if it is bacterial in origin [1.0]. Acute rhinosinusitis is defined by symptom duration of less than 4 weeks. Acute bacterial sinusitis is usually a secondary infection resulting from sinus ostia obstruction, impaired mucus clearance mechanisms caused by an acute viral upper respiratory tract infection, or both. According to epidemiologic estimates, only 0.2% to 2% of viral upper respiratory tract infections in adults are complicated by bacterial rhinosinusitis. The gold standard for diagnosis of bacterial sinusitis is sinus puncture, and Streptococcus pneumoniae and Haemophilus influenzae are the bacteria most commonly isolated from infected maxillary sinuses. However, sinus puncture is an invasive procedure seldom performed in primary care. Because no simple and accurate office-based test for acute bacterial sinusitis exists, clinicians rely on clinical findings to make the diagnosis. However, signs and symptoms of acute bacterial sinusitis and those of prolonged viral upper respiratory tract infections are very similar, resulting in frequent misclassification of viral cases [1.1, 1.2]. Diagnosis: Bacterial Compared with Viral Overdiagnosis of acute bacterial rhinosinusitis is not surprising, considering the lack of specific clinical features that distinguish it from nonbacterial upper respiratory tract infections. Often, patients and physicians believe that an upper respiratory tract infection has gone on too long and that antibiotic treatment is therefore needed. In a study of the natural history of rhinovirus illness, length of illness ranged from 1 to 33 days. Most patients were well or nearly well in 7 to 10 days, and one fourth of patients were still symptomatic after 14 days. Bacterial rhinosinusitis is not common in patients whose symptoms have lasted less than 7 days; therefore, presence of symptoms for at least 7 days is a moderately sensitive but nonspecific predictor of bacterial rhinosinusitis [3.0]. Since 1976, seven investigators have published reports attempting to identify signs and symptoms specific to acute bacterial rhinosinusitis. All of these studies have limitations, such as a suboptimal gold standard or selection criteria that allowed the inclusion of patients whose symptoms had been present for more than 1 month. However, considering the results of all seven studies, purulent nasal discharge along with maxillary tooth or facial pain (especially when unilateral), unilateral sinus tenderness, and worsening of symptoms after initial improvement seem to be helpful findings for predicting a higher likelihood of bacterial infection in patients with rhinosinusitis-like symptoms [3.2]. Several investigators have studied the accuracy of sinus radiography in predicting the presence of purulent sinus fluid by using complete opacification, air-fluid level, or various degrees of mucosa thickening as the diagnostic criteria. Complete opacification and air-fluid level are the most specific findings, with specificities of 85% (range, 76% to 91%) and 80% (range, 71% to 87%), respectively. The finding of mucosal thickening has a low specificity, probably no better than that of skilled clinical judgment, which is 40% to 50%. The absence of all three findings has an estimated sensitivity of approximately 90% and is helpful in ruling out bacterial rhinosinusitis. Given these test characteristics and the known high prevalence of abnormal radiography findings in patients with viral rhinosinusitis, sinus radiography has limited value in routine diagnosis of acute bacterial rhinosinusitis [4.0]. Treatment For acute bacterial rhinosinusitis, randomized, double-blind, placebo-controlled trials of antibiotic treatment using pretreatment and post-treatment culture of sinus aspirates have not been performed. Five randomized, double-blind clinical trials with good methods have compared antibiotic treatment with placebo for acute rhinosinusitis in adults. Two recent meta-analyses, one under the auspices of the Cochrane Collaboration and the other under contract from the Agency for Healthcare Research and Quality (AHRQ), have recently been published. Both concluded that although antibiotics are statistically more efficacious than placebo in reducing or eliminating symptoms at 10 and 14 days, the effect size (degree of benefit) is relatively small. Moreover, most patients who receive placebo improve without antibiotic therapy. The AHRQ report pointed out that symptoms improved or resolved in 69% (CI, 57% to 79%) of patients by 14 days without any antibiotic treatment at all. When the 40% to 50% prevalence of bacterial rhinosinusitis in patients whose diagnosis is determined by signs and symptoms and the modest effectiveness of antibiotic treatment were considered, a cost-effectiveness model sponsored by the AHRQ favored antibiotic treatment for patients with moderate to severe symptoms and symptomatic treatment for those with mild symptoms [5.05.3]. Summary In summary, most cases of acute rhinosinusitis diagnosed in ambulatory care are caused by uncomplicated viral upper respiratory tract infections. Bacterial and viral rhinosinusitis are difficult to differentiate on clinical grounds. The clinical diagnosis of acute bacterial rhinosinusitis should be reserved for patients with rhinosinusitis symptoms lasting 7 days or more who have purulent nasal secretions and maxillary facial or tooth pain or tenderness. Patients who have symptoms of rhinosinusitis for less than 7 days are unlikely to have bacterial infection. Sinus radiography is not recommended for diagnosis in routine cases. Acute bacterial rhinosinusitis resolves without antibiotic treatment in most cases. Symptomatic treatment and reassurance are the preferred initial management strategy for patients with mild symptoms. Antibiotic therapy should be reserved for patients with severe symptoms who meet the criteria for the clinical diagnosis of acute bacterial rhinosinusitis, regardless of duration of illness. Initial antibiotic treatment should be with narrow-spectrum agents. On the basis of clinical trials, amoxicillin, doxycycline, and trimethoprimsulfamethoxazole are the favored antibiotics [5.4, 5.5]. Recommendations Recommendation 1. Sinus radiography is not recommended for the diagnosis of uncomplicated sinusitis. The greatest barrier to efficient antibiotic treatment of acute bacterial rhinosinusitis is lack of a simple and accurate diagnostic test. Until a better test is widely available in office practice, the office diagnosis of acute bacterial rhinosinusitis will remain imprecise. Duration of illness is a useful clinical criterion because acute bacterial sinusitis is not common in patients whose symptoms last for less than 7 days. Patients who do not have persistent purulent nasal drainage, maxillary facial or tooth pain or tenderness, or both are unlikely to have bacterial rhinosinusitis, regardless of duration of illness. Recommendation 2. Acute bacterial sinusitis does not require antibiotic treatment, especially if symptoms are mild or moderate. Because most patients with a clinical diagnosis of rhinosinusitis improve without antibiotic treatment, symptomatic treatment or reassurance is the preferred initial management strategy. Appropriate doses of analgesics, antipyretics, and decongestants should be offered, as well as patient education about the chosen management strategy. Recommendation 3. Patients with severe or persistent moderate symptoms and specific findings of bacterial sinusitis should be treated with antibiotics. Narrow-spectrum antibiotics are reasonable first-line agents. In most cases, antibiotics should be used only for patients with the specific findings of persistent purulent nasal discharge and facial pain or tenderness who are not improving after 7 days or those with severe symptoms of rhinosinusitis, regardless of duration. On the basis of clinical trials, amoxicillin, doxycycline, or trimethoprimsulfamethoxazole are the favored antibiotics.

Principles of appropriate antibiotic use for acute pharyngitis in adults : Background

The following principles of appropriate antibiotic use for adults with acute pharyngitis apply to immunocompetent adults without complicated comorbid conditions, such as chronic lung or heart disease, and history of rheumatic fever. They do not apply during known outbreaks of group A streptococcus.1. Group A beta-hemolytic streptococcus (GABHS) is the causal agent in approximately 10% of adult cases of pharyngitis. The large majority of adults with acute pharyngitis have a self-limited illness, for which supportive care only is needed.2. Antibiotic treatment of adult pharyngitis benefits only those patients with GABHS infection. All patients with pharyngitis should be offered appropriate doses of analgesics and antipyretics, as well as other supportive care.3. Limit antibiotic prescriptions to patients who are most likely to have GABHS infection. Clinically screen all adult patients with pharyngitis for the presence of the four Centor criteria: history of fever, tonsillar exudates, no cough, and tender anterior cervical lymphadenopathy (lymphadenitis). Do not test or treat patients with none or only one of these criteria, since these patients are unlikely to have GABHS infection. For patients with two or more criteria the following strategies are appropriate: a) Test patients with two, three, or four criteria by using a rapid antigen test, and limit antibiotic therapy to patients with positive test results; b) test patients with two or three criteria by using a rapid antigen test, and limit antibiotic therapy to patients with positive test results or patients with four criteria; or c) do not use any diagnostic tests, and limit antibiotic therapy to patients with three or four criteria. 4. Throat cultures are not recommended for the routine primary evaluation of adults with pharyngitis or for confirmation of negative results on rapid antigen tests when the test sensitivity exceeds 80%. Throat cultures may be indicated as part of investigations of outbreaks of GABHS disease, for monitoring the development and spread of antibiotic resistance, or when such pathogens as gonococcus are being considered.5. The preferred antibiotic for treatment of acute GABHS pharyngitis is penicillin, or erythromycin in a penicillin-allergic patient.

Principles of appropriate antibiotic use for treatment of uncomplicated acute bronchitis: Background

n Abstractn n The following principles of appropriate antibiotic use for adults with acute bronchitis apply to immunocompetent adults without complicating comorbid conditions, such as chronic lung or heart disease.n n 1.n The evaluation of adults with an acute cough illness or a presumptive diagnosis of uncomplicated acute bronchitis should focus on ruling out serious illness, particularly pneumonia. In healthy, nonelderly adults, pneumonia is uncommon in the absence of vital sign abnormalities or asymmetrical lung sounds, and chest radiography is usually not indicated. In patients with cough lasting 3 weeks or longer, chest radiography may be warranted in the absence of other known causes.n n n 2.n Routine antibiotic treatment of uncomplicated acute bronchitis is not recommended, regardless of duration of cough. If pertussis infection is suspected (an unusual circumstance), a diagnostic test should be performed and antimicrobial therapy initiated.n n n 3.n Patient satisfaction with care for acute bronchitis depends most on physician–patient communication rather than on antibiotic treatment.n n n n [Gonzales R, Bartlett JG, Besser RE, Cooper RJ, Hickner JM, Hoffman JR, Sande MA. Principles of appropriate antibiotic use for treatment of uncomplicated acute bronchitis: background. Ann Emerg Med. June 2001;37:720-727.]n n

Principles of appropriate antibiotic use for treatment of acute respiratory tract infections in adults: Background, specific aims, and methods

The need to decrease excess antibiotic use in ambulatory practice has been fueled by the epidemic increase in antibiotic-resistant Streptococcus pneumoniae. The majority of antibiotics prescribed to adults in ambulatory practice in the United States are for acute sinusitis, acute pharyngitis, acute bronchitis, and nonspecific upper respiratory tract infections (including the common cold). For each of these conditions--especially colds, nonspecific upper respiratory tract infections, and acute bronchitis (for which routine antibiotic treatment is not recommended)--a large proportion of the antibiotics prescribed are unlikely to provide clinical benefit to patients. Because decreasing community use of antibiotics is an important strategy for combating the increase in community-acquired antibiotic-resistant infections, the Centers for Disease Control and Prevention convened a panel of physicians representing the disciplines of internal medicine, family medicine, emergency medicine, and infectious diseases to develop a series of Principles of Appropriate Antibiotic Use for Treatment of Acute Respiratory Tract Infections in Adults. These principles provide evidence-based recommendations for evaluation and treatment of adults with acute respiratory illnesses.This paper describes the background and specific aims of and methods used to develop these principles. The goal of the principles is to provide clinicians with practical strategies for limiting antibiotic use to the patients who are most likely to benefit from it. These principles should be used in conjunction with effective patient educational campaigns and enhancements to the health care delivery system that facilitate nonantibiotic treatment of the conditions in question.

Principles of appropriate antibiotic use for acute rhinosinusitis in adults: Background

The following principles of appropriate antibiotic use for adults with acute rhinosinusitis apply to the diagnosis and treatment of acute maxillary and ethmoid rhinosinusitis in adults who are not immunocompromised. Most cases of acute rhinosinusitis diagnosed in ambulatory care are caused by uncomplicated viral upper respiratory tract infections. Bacterial and viral rhinosinusitis are difficult to differentiate on clinical grounds. The clinical diagnosis of acute bacterial rhinosinusitis should be reserved for patients with rhinosinusitis symptoms lasting 7 days or more who have maxillary pain or tenderness in the face or teeth (especially when unilateral) and purulent nasal secretions. Patients with rhinosinusitis symptoms that last less than 7 days are unlikely to have bacterial infection, although rarely some patients with acute bacterial rhinosinusitis present with dramatic symptoms of severe unilateral maxillary pain, swelling, and fever. Sinus radiography is not recommended for diagnosis in routine cases. Acute rhinosinusitis resolves without antibiotic treatment in most cases. Symptomatic treatment and reassurance is the preferred initial management strategy for patients with mild symptoms. Antibiotic therapy should be reserved for patients with moderately severe symptoms who meet the criteria for the clinical diagnosis of acute bacterial rhinosinusitis and for those with severe rhinosinusitis symptoms-especially those with unilateral facial pain-regardless of duration of illness. For initial treatment, the most narrow-spectrum agent active against the likely pathogens, Streptococcus pneumoniae and Haemophilus influenzae, should be used.