The diagnosis of strep throat in adults in the emergency room

Patients derogate physicians who use a computer-assisted diagnostic aid

OBJECTIVE

To ascertain whether a physician who uses a computer-assisted diagnostic support system (DSS) would be rated less capable than a physician who does not.

METHOD

Students assumed the role of a patient with a possible ankle fracture (experiment 1) or a possible deep vein thrombosis (experiment 2). They read a scenario that described an interaction with a physician who used no DSS, one who used an unspecified DSS, or one who used a DSS developed at a prestigious medical center. Participants were then asked to rate the interaction on 5 criteria, the most important of which was the diagnostic ability of the physician. In experiment 3, 74 patients in the waiting room of a clinic were randomly assigned to the same 3 types of groups as used in experiment 1. In experiment 4, 131 3rd- and 4th-year medical students read a scenario of a physician-patient interaction and were randomly assigned to 1 of 4 groups: the physician used no DSS, heeded the recommendation of a DSS, defied a recommendation of a DSS by treating in a less aggressive manner, or defied a recommendation of a DSS by treating in a more aggressive manner .

RESULTS

The participants always deemed the physician who used no decision aid to have the highest diagnostic ability.

CONCLUSION

Patients may surmise that a physician who uses a DSS is not as capable as a physician who makes the diagnosis with no assistance from a DSS.

[Clinical and therapeutic management of respiratory tract infections. Consensus document of the Andalusian infectious diseases society and the Andalusian family and comunitary medicine society]

Respiratory tract infections are frequent and they are one of the commonest causes of antibiotic prescription. However, there are few clinical guidelines that consider this group of infections. This document has been written by the Andalusian Infectious Diseases Society and the Andalusian Family and Community Medicine Society. The primary objective has been to define the recommendations for the diagnosis and antibiotic treatment of respiratory tract infections apart from pneumonia. The clinical syndromes evaluated have been: a) pharyngitis; b) sinusitis; c) acute otitis media and otitis externa; d) acute bronchitis, laryngitis, epiglottitis; e) acute exacerbation of chronic bronchitis; and f) respiratory infectious in patients with bronchiectasis. This document has focused on immunocompetent patients.

Throat culture is necessary after negative rapid antigen detection tests

This study was conducted to determine if culture confirmation is needed for a negative rapid antigen detection test. Data on 18,509 tests done in patients younger than 18 years old were reviewed. Of the 14,167 (76.5%) that were negative, 968 (6.8%) were associated with positive cultures. No significant seasonal variation was noted. Significant differences were found between hospital and pediatric practices in the percentage of patients with a negative rapid antigen detection test who actually had group A beta-hemolytic streptococcus (3.5% to 9.8%). This study supports the recommendation of culture confirmation of a negative rapid antigen detection test and validation of results within an individual practice if confirmatory cultures are not being performed. This study showed a high false-negative rate of the negative rapid antigen detection test and variation among hospital and pediatric practices for rates of positive culture after a negative rapid antigen detection test.

[Clinical and therapeutic management of respiratory tract infections. Consensus document of the Andalusian Infectious Diseases Society and the Andalusian Family and Community Medicine Society]

Respiratory tract infections are frequent and they are one of the commonest causes of antibiotic prescription. However, there are few clinical guidelines that consider this group of infections. This document has been written by the Andalusian Infectious Diseases Society and the Andalusian Family and Community Medicine Society. The primary objective has been to define the recommendations for the diagnosis and antibiotic treatment of respiratory tract infections apart from pneumonia. The clinical syndromes evaluated have been: a) pharyngitis; b) sinusitis; c) acute otitis media and otitis externa; d) acute bronchitis, laryngitis, epiglottitis; e) acute exacerbation of chronic bronchitis; and f) respiratory infectious in patients with bronchiectasis. This document has focused on immunocompetent patients.

Severe acute pharyngitis caused by group C streptococcus

INTRODUCTION

Adult group C beta-hemolytic streptococcal pharyngitis has a prevalence of approximately 5%. It can present with a broad spectrum of severity.

CASE REPORT

We report a 30-year-old woman who presented with severe Group C streptococcal pharyngitis.

DISCUSSION

She presented with a 9-day history of progressive symptoms, including fever, sore throat, neck swelling, and recent onset of hoarseness. In the 9 days before the emergency room (ER) presentation, the patient had visited the ER twice complaining of a sore throat. At both visits, the physicians performed rapid antigen strep testing. Each time her test was negative and the physicians recommended symptomatic therapy. Her symptoms continued to worsen leading to her repeat presentation. At this time she had severe pharyngitis with markedly enlarged tonsils. Neck CT excluded peritonsillar abscess. Rapid strep testing was again negative, but her throat culture grew group C beta-hemolytic streptococcus.

CONCLUSION

This presentation illustrates the importance of a systematic approach to evaluating patients with negative rapid strep tests and worsening pharyngitis.

Pharyngitis management: defining the controversy

Despite numerous controlled trials, clinical practice guidelines and cost-effective analyses, controversy persists regarding the appropriate management strategy for adult pharyngitis. In this perspective, we explore this controversy by comparing two competing clinical guidelines. Although the guidelines appear to make widely diverging recommendations, we show that the controversy centers on only a small proportion of patients: those presenting with severe pharyngitis. We examine recently published data to illustrate that this seemingly simple problem of strep throat remains a philosophical issue: should we give primacy to relieving acute time-limited symptoms, or should we emphasize the potential societal risk of antibiotic resistance? We accept potentially over treating a minority of adult pharyngitis patients with the most severe presentations to reduce suffering in an approximately equal number of patients who will have false negative test results if the test-and-treat strategy were used.

Use of a personal digital assistant for managing antibiotic prescribing for outpatient respiratory tract infections in rural communities

OBJECTIVE

To assess the acceptability and usage of a standalone personal digital assistant (PDA)-based clinical decision-support system (CDSS) for the diagnosis and management of acute respiratory tract infections (RTIs) in the outpatient setting.

DESIGN

Observational study performed as part of a larger randomized trial in six rural communities in Utah and Idaho from January 2002 to March 2004. Ninety-nine primary care providers received a PDA-based CDSS for use at the point-of-care, and were asked to use the tool with at least 200 patients with suspected RTIs.

MEASUREMENTS

Clinical data were collected electronically from the devices at periodic intervals. Providers also completed an exit questionnaire at the end of the study period.

RESULTS

Providers logged 14,393 cases using the CDSS, the majority of which (n=7624; 53%) were from family practitioners. Overall adherence with CDSS recommendations for the five most common diagnoses (pharyngitis, otitis media, sinusitis, bronchitis, and upper respiratory tract infection) was 82%. When antibiotics were prescribed (53% of cases), adherence with the CDSS-recommended antibiotic was high (76%). By logistic regression analysis, the odds of adherence with CDSS recommendations increased significantly with each ten cases completed (P=0.001). Questionnaire respondents believed the CDSS was easy to use, and most (44/65; 68%) did not believe it increased their encounter time with patients, regardless of prior experience with PDAs.

CONCLUSION

A standalone PDA-based CDSS for acute RTIs used at the point-of-care can encourage better outpatient antimicrobial prescribing practices and easily gather a rich set of clinical data.

Comparison of clinical prediction rules for management of pharyngitis in settings with limited resources

OBJECTIVE

To compare the effectiveness of several clinical prediction rules for culture-positive streptococcal pharyngitis in a single group of patients in a setting in which clinicians routinely treat all cases of pharyngitis presumptively, without laboratory data.

STUDY DESIGN

A MEDLINE search identified clinical prediction rules for streptococcal pharyngitis in children. Each rule was applied analytically to data from 410 children in Cairo, Egypt with clinical pharyngitis, in whom throat cultures were performed. The diagnostic effectiveness of these rules for predicting a positive culture were assessed and compared.

RESULTS

Seven prediction rules were identified. Of these 7 rules, 4 were developed in North American children, 1 was recommended by the World Health Organization (WHO), and 2 were developed in Egypt. In the Cairo children, the WHO rule was the least sensitive, at 12%. The 6 other rules had sensitivities ranging from 81% to 99% and specificities ranging from 4% to 40%; 2 rules seemed to be effective, with diagnostic odds ratios of 5.2 and 6.1.

CONCLUSIONS

The prediction rules demonstrated variable diagnostic effectiveness in the Egyptian children. Without laboratory testing, 2 clinical rules detected > 90% of cases of pharyngitis with positive culture for group A streptococcus and reduced overtreatment of culture-negative cases by approximately 40%. Selected clinical prediction rules have useful characteristics in settings of limited resources and need further validation.

Clinicians' management of children and adolescents with acute pharyngitis

OBJECTIVE

Sore throat is a common complaint in children and adolescents. With increasing antimicrobial resistance because of antimicrobial overuse, accurate diagnosis is imperative. Appropriate management of acute pharyngitis depends on proper use and interpretation of clinical findings, rapid antigen-detection tests, and throat cultures. We surveyed pediatricians and family physicians to evaluate their management strategies for children and adolescents with acute pharyngitis and to assess the availability and use of diagnostic tests in office practice.

METHODS

In 2004, surveys were mailed to a random sample of 1000 pediatrician members of the American Academy of Pediatrics and 1000 family physician members of the American Academy of Family Physicians. We assessed factors associated with physicians using an appropriate management strategy for treating acute pharyngitis.

RESULTS

Of 948 eligible responses, 42% of physicians would start antimicrobials before knowing diagnostic test results and continue them despite negative results, with 27% doing this often or always. When presented with clinical scenarios of patients with acute pharyngitis, < or =23% chose an empirical approach, 32% used an inappropriate strategy for a child with pharyngitis suggestive of group A Streptococcus, and 81% used an inappropriate strategy for a child with findings consistent with viral pharyngitis. Plating cultures in the office was associated with an appropriate management strategy, although not statistically significant. Solo/2-person practice and rural location were both independent factors predicting inappropriate strategies.

CONCLUSIONS

There is much room for improvement in the management of acute pharyngitis in children and adolescents. Most physicians use appropriate management strategies; however, a substantial number uses inappropriate ones, particularly for children with likely viral pharyngitis. Efforts to help physicians improve practices will need to be multifaceted and should include health policy and educational approaches.

Streptococcus A in paediatric accident and emergency: are rapid streptococcal tests and clinical examination of any help?

BACKGROUND

Rapid streptococcal tests (RSTs) for streptococcal pharyngitis have made diagnosis at once simpler and more complicated. The American Academy of Pediatrics recommends that all RSTs be confirmed by a follow up throat culture unless local validation has proved the RST to be equally sensitive.

AIMS

To evaluate (a) RST as a single diagnostic tool, compared with RST with or without throat culture; (b) clinical diagnosis and the relative contribution of different symptoms.

METHODS

The study included 213 patients with clinical signs of pharyngitis. Throat swabs were analysed using Quickvue+ Strep A Test; negative RSTs were backed up by throat culture. Thirteen clinical features commonly associated with strep throat were analysed using backward stepwise logistic regression.

RESULTS

Positive results (RST or throat culture) were obtained in 33 patients; RST correctly identified 21. Eleven samples were false negative on RST. At a strep throat prevalence of 15.9%, sensitivity of RST was 65.6% (95% CI 46.8% to 81.4%) and specificity 99.4% (96.7% to 99.9%). Sensitivity of clinical diagnosis alone was 57% (34% to 78%) and specificity 71% (61% to 80%). Clinically, only history of sore throat, rash, and pyrexia contributed to the diagnosis of strep throat (p<0.05).

CONCLUSION

The high specificity of RST facilitates early diagnosis of strep throat. However, the low sensitivity of RST does not support its use as a single diagnostic tool. The sensitivity in the present study is markedly different from that reported by the manufacturer. Clinical examination is of limited value in the diagnosis of strep throat. It is important to audit the performance of new diagnostic tests, previously validated in different settings.

Airway infectious disease emergencies

Upper and lower respiratory infections are encountered commonly in the emergency department. Visits resulting from occurrences of respiratory disease account for 10% of all pediatric emergency department visits and 20% of all pediatric hospital admissions. Causes of upper airway infections include croup, epiglottitis, retropharyngeal abscess, cellulitis, pharyngitis, and peritonsillar abscesses. Lower airway viral and bacterial infections cause illnesses such as pneumonia and bronchiolitis. Signs and symptoms of upper and lower airway infections overlap, but the differentiation is important for appropriate treatment of these conditions. This article reviews the varied clinical characteristics of upper and lower airway infections.

Optimal management of adults with pharyngitis--a multi-criteria decision analysis

BACKGROUND

Current practice guidelines offer different management recommendations for adults presenting with a sore throat. The key issue is the extent to which the clinical likelihood of a Group A streptococcal infection should affect patient management decisions. To help resolve this issue, we conducted a multi-criteria decision analysis using the Analytic Hierarchy Process.

METHODS

We defined optimal patient management using four criteria: 1) reduce symptom duration; 2) prevent infectious complications, local and systemic; 3) minimize antibiotic side effects, minor and anaphylaxis; and 4) achieve prudent use of antibiotics, avoiding both over-use and under-use. In our baseline analysis we assumed that all criteria and sub-criteria were equally important except minimizing anaphylactic side effects, which was judged very strongly more important than minimizing minor side effects. Management strategies included: a) No test, No treatment; b) Perform a rapid strep test and treat if positive; c) Perform a throat culture and treat if positive; d) Perform a rapid strep test and treat if positive; if negative obtain a throat culture and treat if positive; and e) treat without further tests. We defined four scenarios based on the likelihood of group A streptococcal infection using the Centor score, a well-validated clinical index. Published data were used to estimate the likelihoods of clinical outcomes and the test operating characteristics of the rapid strep test and throat culture for identifying group A streptococcal infections.

RESULTS

Using the baseline assumptions, no testing and no treatment is preferred for patients with Centor scores of 1; two strategies--culture and treat if positive and rapid strep with culture of negative results--are equally preferable for patients with Centor scores of 2; and rapid strep with culture of negative results is the best management strategy for patients with Centor scores 3 or 4. These results are sensitive to the priorities assigned to the decision criteria, especially avoiding over-use versus under-use of antibiotics, and the population prevalence of Group A streptococcal pharyngitis.

CONCLUSION

The optimal clinical management of adults with sore throat depends on both the clinical probability of a group A streptococcal infection and clinical judgments that incorporate individual patient and practice circumstances.

Role of rapid antigen detection test for the diagnosis of group-A ß-hemolytic streptococcus in patients with pharyngotonsillitis

Group A ß-hemolytic streptococcus (GAS) is an important pharyngotonsillitis etiologic agent. Correct etiologic diagnosis and early treatment prevent suppurative and non-suppurative complications of streptococcal pharyngotonsillitis, however, clinical diagnostic methods are not reliable. Within this context, rapid detection methods of GAS antigen are useful to diagnose this agent.

Aim

The objective of the present study was to determine the sensitivity and specificity of rapid GAS antigen detection tests used in Brazil.

Study Design

Clinical prospective.

Methods

Eighty-one patients with clinical diagnosis of acute pharyngotonsillitis seen at the otorhinolaryngology emergency department of University Hospital, FMUSP, between May 2001 and April 2002, were submitted to two simultaneous collections of oropharyngeal material using swabs. Rapid GAS antigen detection test was compared to culture on blood agar, the gold standard for the diagnosis of this etiologic agent.

Results

Among the 81 studied patients, the rapid test was positive in 56% and negative in 44%. GAS growth in culture was observed for 40.7% of the patients. The sensitivity and specificity of the rapid test were, respectively, 93.9% and 68.7%, and the negative and positive predictive values were 94.2 and 67.4%, respectively.

Conclusions

We concluded that the high sensitivity of the test permits its use for the identification of patients with GAS. Rapid streptococcal antigen detection tests have been shown to be an important supporting tool in the etiologic diagnosis of pharyngotonsillitis.

Viewpoint: suggestions for a shift in teaching clinical skills to medical students: the reflective clinical examination

How medical students are taught physical examination (PE) skills appears to have changed little since the 1950s. Textbooks are organized according to organ systems and describe methods of eliciting and recording history and PE data using a routine format. In many medical schools, the preclinical teaching programs for clinical examination skills similarly emphasize an orderly collection of data. Teaching students to use diagnostic reasoning is postponed until students have learned history-taking and PE skills. The authors propose three modifications to this educational approach. First, rather than performing the clinical examination using a routine format, students should be encouraged to form diagnostic hypotheses early on while listening to the patient's narrative, and conduct the subsequent search for history and PE data in a reflective way in order to confirm or refute these hypotheses. Second, the authors propose that interviewing patients and conducting the PE be taught by one-on-one tutoring until students achieve mastery. Last, they suggest that the PE be guided not only by students' diagnostic hypotheses, but also by patients' expectations. These modifications are consistent with current trends in medical education that encourage a reflective practice and problem-based learning (PBL), and they also introduce medical students to the precepts of clinical reasoning. The authors suggest that challenging students to seek specific physical findings may increase the likelihood of detecting findings when they are present, and may transform patient interviewing and conducting the PE from routine activities into intellectually exciting experiences.

Management of Sore Throat by Family Physicians in Northeastern Poland: Possible Benefits of Applying Clinical Algorithm

BACKGROUND

The objective of this study was to describe current sore throat management practices among family physicians and to estimate potential benefits of applying clinical algorithm - Centor's scale (presence of tonsillar exudates, fever, lymphadenopathy and absence of cough) in decision-making process.

METHODS

Each of 44 participating family physicians was asked to fill in questionnaires for 30 consecutive patients with respiratory tract infection.

RESULTS

Almost all decisions were made on clinical grounds. Among 169 adult patients with the clinical diagnosis of bacterial pharyngitis only 55% fulfilled 3 or more criteria on Centor's scale.

CONCLUSIONS

Family physicians overdiagnose bacterial pharyngitis. Screening adult patients with Centor's criteria would probably lead to a reduction in the prescribing of antibiotics.

Role of rapid antigen detection test for the diagnosis of group A beta-hemolytic streptococcus in patients with pharyngotonsillitis

Group A β -hemolytic streptococcus (GAS) is an important pharyngotonsillitis etiologic agent. Correct etiologic diagnosis and early treatment prevent suppurative and non-suppurative complications of streptococcal pharyngotonsillitis; however, clinical diagnosis is not reliable. Within this context, rapid detection methods of GAS antigen are useful to diagnose this agent.

Aim

The objective of the present study was to determine sensitivity and specificity of rapid GAS antigen detection tests used in Brazil.

Study design

Clinical prospective. Method: Eighty-one patients with clinical diagnosis of acute pharyngotonsillitis seen at the otorhinolaryngology emergency department of the University Hospital, FMUSP, between May 2001 and April 2002 were submitted to two simultaneous collections of oropharyngeal material using swabs. The rapid GAS antigen detection test was compared to culture on blood agar, the gold standard for the diagnosis of this etiologic agent.

Results

Among the 81 patients studied, the rapid test was positive in 56% and negative in 44%. GAS growth in culture was observed in 40.7% of the patients. Sensitivity and specificity of the rapid test were, respectively, 93.9% and 68.7%, and the negative and positive predictive values were 94.2 and 67.4%, respectively. Conclusions: We concluded that high sensitivity of the test allows its use in the identification of patients with GAS. Rapid streptococcal antigen detection tests have been shown to be an important adjuvant tool in the etiologic diagnosis of pharyngotonsillitis.

The role of point of care testing for patients with acute pharyngitis

BACKGROUND

There is no consensus favoring a particular strategy for evaluating patients with pharyngitis.

OBJECTIVE

To compare a clinical decision aid and a rapid office-based point of care (POC) test with routine culture for group A beta-hemolytic streptococcus (GAS).

DESIGN

Prospective observational study.

PARTICIPANTS

Among 179 patients enrolled, 150 were eligible and 148 had POC testing and cultures initially performed.

MEASUREMENTS

An encounter form included eligibility criteria, clinical information based upon the Centor rule, and treatment provided. Sensitivity and specificity of POC test compared to routine culture for GAS.

RESULTS

Thirty-eight patients (25.7%) had a positive GAS culture. The POC test was 92.1% sensitive (95% confidence interval [CI] 80% to 98%) and 100% specific (95% CI 97% to 100%). Although the Centor rule did not adequately discriminate among symptomatic patients with or without GAS (receiver operating curve area 0.63), the 3 patients with a false-negative POC test had a Centor score of less than 2. Among patients with a negative POC test, 26% initially received antibiotics.

CONCLUSIONS

For patients with a Centor score of > or =2, a POC test was highly sensitive for GAS. Future studies should confirm these results and assess whether implementation of POC testing as part of a local practice guideline can decrease variability in testing and treatment.

The effect of written information on adherence to antibiotic treatment in acute sore throat

A randomised clinical trial was conducted to establish whether written instructions, in addition to verbal ones, significantly improve adherence to antibiotic treatment for acute sore throat in comparison with verbal instructions only. Patients were selected by consecutive sampling at seven primary healthcare surgeries. The pill count average was 87.4+/-25.2% and it was higher in the intervention group (93.7+/-24.5%) than in the control group (81.1+/-24.5%) (P < 0.05). Absolute risk reduction was 14% (95% confidence interval (CI), -3.77 to 26.56); relative risk reduction was 24.9% (95% CI, -11.04 to 58.28); the number needed to treat was 8.77. Written instructions, in addition to verbal ones, significantly improve compliance with antibiotic treatment in tonsillitis of acute sore throat in comparison with verbal instructions only.

[Effectiveness of the implementation of a clinical program (CP) for the management of acute pharyngitis in adults]

OBJECTIVE

To reduce variability in the diagnosis and treatment of acute pharyngitis, reaching an established standard of quality.

DESIGN

Noncontrolled intervention study, consisting of sequential quality improvement cycles.

SETTING

Unscheduled attention at the outpatient clinic of an internal medicine service.

PARTICIPANTS

a baseline sample and 7 bimonthly follow-up samples were randomly selected from 2764 visits for acute pharyngitis and tonsillitis, resulting in a total sample of 910 visits. We include patients of both sexes who were at least 15 years old. A staff of 19 physicians are in charge of the outpatient clinic. Seventy five visits (8.2%) were eliminated because of lack of data. INTERVENTIONS (CLINICAL PROGRAM): a) elaboration of the CP; b) information to the physicians; c) monitoring of the indicators every two months; and d) introduction of corrective measures after the basal measurement and after each monitoring, including the communication to the professionals of the global and individual results.

MAIN MEASUREMENTS

The following indicators were obtained from the computerized medical record: use of rapid antigen test for streptococcus (URAT), total antibiotic prescription (TAP), suitable antibiotic use (SAU) and first choice antibiotic selection (FCAS). The respective standards were adapted from international guidelines with the consensus of the intervening professionals, namely: URAT 50%; TAP 20%; SAU 100% and FCAS 100%.

STATISTICAL ANALYSIS

the indicators temporal variations were analyzed according the chi square test for linear trend.

RESULTS

the URAT increased significantly from the basal 30% and reached the 50% standard (P=.01). The basal TAP was 36% and it did not change significantly with the intervention (P=.53). The SAU improved significantly from basal 34% to values between 60 and 80% (P<.0001), about half of the maximal attainable improvement. The FCAS was 18% in the basal sample and climbed to 75% in the last measurements (P<.0001), about two thirds of the maximal attainable improvement.

CONCLUSIONS

Although the physicians' attitude has changed, it is still a long way from the established standard. It is necessary to maintain the monitoring of the quality indicators and the regular and customized interventions until the consolidation of the practice is achieved.

Human neutrophil lipocalin (HNL) as a diagnostic tool in children with acute infections: a study of the kinetics

AIM

To study the changes in blood of human neutrophil lipocalin (HNL) and C-reactive protein (CRP) during the course of an acute infection in children.

METHODS

Children (n=92) hospitalized with symptoms and signs of acute infections were included and categorized into five groups, i.e. bacterial infection, suspected bacterial infection, viral infection, suspected viral infection and others. Blood was taken at admittance and the following 3-4 d for the measurement of CRP and HNL.

RESULTS

Both CRP and HNL were significantly raised at admittance in bacterial infection as compared to viral infection (p<0.001). After 25-48 h, 83% of the children with bacterial infections still had raised CRP levels in contrast to 11% having raised HNL levels. The levels of CRP, but not those of HNL, were significantly correlated to days of symptoms before admission.

CONCLUSIONS

HNL is a promising diagnostic tool in the distinction of acute infections caused by bacteria or virus. The differences in the kinetics of CRP and HNL make HNL a better marker for monitoring antibacterial treatment, since HNL is probably elevated only when an active bacterial infection is at hand.

Diagnosis and treatment of pharyngitis in children

Acute pharyngitis is one of the most common illnesses for which children visit primary care physicians. Most cases of acute pharyngitis in children are caused by viruses and are benign and self-limited. Group A beta-hemolytic streptococcus is the most important of the bacterial causes of acute pharyngitis. Strategies for diagnosis and treatment of acute pharyngitis are directed at distinguishing children with viral pharyngitis, who would not benefit from antimicrobial therapy, from children with group A beta-hemolytic streptococcal pharyngitis, for whom antimicrobial therapy would be beneficial. Making this distinction is crucial in attempting to minimize the unnecessary use of antimicrobial agents in children.

Papel do teste de detecção rápida do antígeno do estreptococcus pyogenes do grupo a em pacientes com faringoamigdalites

O Streptococcus pyogenes do grupo A (SGA) é o agente etiológico mais comum das faringoamigdalites (FA). O diagnóstico etiológico correto e tratamento adequado evitam complicações supurativas e não-supurativas da faringoamigdalite estreptocócica, entretanto, métodos clínicos de diagnóstico não são confiáveis. Os métodos rápidos de detecção do antígeno do SGA podem ser utilizados no diagnóstico deste agente e evitar uso indevido de antibióticos. OBJETIVOS: Os autores objetivaram avaliar a sensibilidade e especificidade dos testes rápidos para detecção do antígeno do SGA em nosso meio. FORMA DE ESTUDO: Clínico prospectivo. CASUÍSTICA E MÉTODO: Oitenta e um pacientes com faringoamigdalite aguda, atendidos no PS-ORL do Hospital das Clínicas da FMUSP, no período de maio de 2001 a abril de 2002, foram submetidos a duas coletas simultâneas de material de orofaringe com swabs. O teste rápido de detecção do SGA foi confrontado com a cultura em placa agar-sangue ("gold standard" para o diagnóstico etiológico). RESULTADOS: De 81 pacientes, 56% tiveram teste rápido positivo e 44% negativo; 40.7% apresentaram crescimento de SGA na cultura; a sensibilidade e especificidade do teste rápido foram, respectivamente, 93,9% e 68,7%. O valor preditivo negativo e positivo foram, respectivamente, 94,2% e 67,4%. COMENTÁRIOS FINAIS: A alta sensibilidade do exame permite utilizá-lo com intuito de identificar pacientes com SGA. Os testes de detecção rápida do antígeno estreptocócico se mostraram uma importante arma coadjuvante no diagnóstico etiológico das faringoamigdalites.

A Multifaceted Intervention to Improve Antimicrobial Prescribing for Upper Respiratory Tract Infections in a Small Rural Community

BACKGROUND

Antibiotic prescribing for upper respiratory tract infections (URTIs) is widespread, is often inappropriate, and may contribute to antibiotic resistance among community-acquired pathogens, such as Streptococcus pneumoniae.

METHODS

A multifaceted intervention involving health care professionals and patients was introduced to a small rural Utah community and included the repetitive use of printed diagnostic and treatment algorithms by professionals. Data on the quantity and class of antibiotic prescribing, which were collected from multiple sources, were measured for the intervention period (from January through June) in 2001 and compared with data for the baseline period during the same months in 2000.

RESULTS

Medicaid claims data revealed that the percentage of patients in the community who received antibiotics for URTIs during the intervention period was 15.6% less than that for the baseline period, whereas the percentage in the rest of rural Utah was relatively stable, with a 1.5% decrease (P=.006). The greatest impact of the intervention was on prescribing for acute bronchitis (decreases of 56.1% and 1.7% in the community and rural Utah, respectively; P=.024) and on prescribing of macrolides (decreases of 13.4% and 0.2% in the community and rural Utah, respectively; P<.001). Community pharmacy data likewise revealed a 17.5% decrease in the rate of antibiotic prescribing during the intervention period (P<.001), with the largest decrease observed for macrolide prescribing (50.9%; P<.001). Chart review data, in contrast, revealed no significant decrease in the percentage of patients with URTI who were prescribed an antibiotic (3.8%; P=.49), although there was a significant decrease of 11.2% in macrolide use (P=.045).

CONCLUSIONS

A multifaceted intervention involving the repetitive use of printed algorithms resulted in modest improvements in antibiotic prescribing for outpatient URTIs, although one data source did not corroborate this. However, macrolide prescribing decreased sharply, irrespective of the source of data.

Antibiotic prescribing for upper respiratory tract infection: the importance of diagnostic uncertainty

OBJECTIVES

Antibiotic misuse for viral upper respiratory tract infections (URI) in children is a significant problem. We determined the influence on antibiotic prescribing of clinical features that may increase concern about possible bacterial infection (age, appearance, fever) in children with URI.

STUDY DESIGN

We created 16 scenarios of children with URI and distributed them by mail survey to 540 pediatricians and family practitioners in Ontario, Canada. The association of patient clinical features, parental pressure, and physician characteristics with antibiotic prescribing was determined through the use of logistic regression analysis.

RESULTS

A total of 257 physicians responded (48%). Poor appearance (OR, 6.50; 95% CI, 5.06 to 3.84), fever above 38.5 degrees C (OR, 1.48; 95% CI, 1.21 to 1.82), and age older than 2 years (OR, 2.27; 95% CI, 1.85 to 2.78) were associated with prescribing, whereas parental pressure was not. Physician characteristics associated with antibiotic use were family practitioner (OR, 1.54; 95% CI, 1.22 to 1.96), increasing number of patients seen per week (OR, 1.05; 95% CI, 1.01 to 1.08 for every 20-patient increase), and increasing physician age (OR, 1.17; 95% CI, 1.11 to 1.24, 5-year increments).

CONCLUSIONS

Clinical factors, which may lead physicians to be concerned about possible bacterial infection in children, are associated with antibiotic use for pediatric URI.

Antibiotic prescribing patterns for sore throat infections in a university-based primary care clinic

BACKGROUND

Recent studies reveal that a high percentage (over 50%) of episodes for upper respiratory tract infections (URTIs) are treated with antibiotics, regardless of appropriateness or the necessity for prescription. We identified antibiotic prescriptions in a primary health care centre (PHC) and evaluated their suitability for sore throat infections. We also explored whether symptoms, signs, diagnosis and antibiotics prescribed differed by gender.

PATIENTS AND METHODS

We collected data on all patients visiting the centre over a period of 12 weeks with a main complaint of sore throat who were prescribed antibiotics after taking a blood count and throat culture. Patients older than 16 years of age were included in the study irrespective of sex, nationality, marital status, occupation or location of residence. The chi square (chi2) statistical test was used in comparing categorical variables. A P value of < 0.05 was considered significant.

RESULTS

During the period of study, 579 patients with URTIs presented to the health centre, from which 339 patients with a sore throat were enrolled. Of the study group, 48.7% (165) were male and 51.3% (174) female, with the majority of patients being under 30 years old (54.3%). Throat cultures were positive in 56 patients (16.5%). Most of patients were diagnosed as having pharyngitis (22.7%), and the most frequently prescribed medicine was an oral penicillin (39.1%). Two hundred eight-six patients (84.4%) had 2 or fewer Centor criteria.

CONCLUSIONS

Throat cultures were positive in only 16.5% of the patients prescribed antibiotics. This indicates that physicians in the health centre of the university are prescribing antibiotics inappropriately and inconsistently. This also highlights the need for more prescriber education, especially as the range of medications available to the general practitioner for prescribing increases.

Group A beta-hemolytic streptococcal pharyngitis in children

Group A beta-hemolytic streptococcus (GABHS) is the most common bacterial cause of acute pharyngitis in children. Because clinical findings can be nonspecific, even experienced physicians cannot reliably diagnose GABHS pharyngitis solely on the basis of clinical presentation. Suspected cases should be confirmed by a throat culture or a rapid antigen detection test before antibiotic therapy is initiated. Microbiologic testing is generally not necessary in patients with pharyngitis whose clinical and epidemiologic findings are not suggestive of GABHS. Clinical score systems have been developed to help physicians decide which patients should undergo diagnostic testing and to reduce the unnecessary use of antibiotics. Antibiotic therapy should be initiated as soon as the diagnosis is confirmed. Penicillin V remains the drug of choice. Alternative therapy, e.g., with cephalosporin or macrolide, is often sought because of penicillin allergy, noncompliance, and treatment failure.

Spectrum bias of a rapid antigen detection test for group A beta-hemolytic streptococcal pharyngitis in a pediatric population

BACKGROUND

Rapid antigen detection testing (RADT) is often performed for diagnosis of group A beta-hemolytic streptococcal (GABHS) pharyngitis among children. Among adults, the sensitivity of this test varies on the basis of disease severity (spectrum bias). A similar phenomenon may occur when this test is used in a pediatric population, which may affect the need for culture confirmation of all negative RADT results.

OBJECTIVES

To assess the performance of a clinical scoring system and to determine whether RADT spectrum bias is present among children who are evaluated for GABHS pharyngitis.

METHODS

Laboratory and clinical records for a consecutive series of pediatric patients who underwent RADT at the Marshfield Clinic between January 2002 and March 2002 were reviewed retrospectively. Patients were stratified according to the number of clinical features present by using modified Centor criteria, ie, history of fever, absence of cough, presence of pharyngeal exudates, and cervical lymphadenopathy. The sensitivity of the RADT was defined as the number of patients with positive RADT results divided by the number of patients with either positive RADT results or negative RADT results but positive throat culture results.

RESULTS

RADT results were positive for 117 of 561 children (21%), and culture results were positive for 35 of 444 children (8%) with negative RADT results. The overall prevalence of GABHS pharyngitis was 27% (95% confidence interval: 23-31%). The prevalence of GABHS pharyngitis was 18% among patients with 0 Centor criteria, 16% among those with 1 criterion, 32% among those with 2 criteria, and 50% among those with 3 or 4 criteria. Spectrum bias was present, inasmuch as RADT sensitivity increased with Centor scores, ie, 47% sensitivity among children with 0 Centor criteria, 65% among those with 1 criterion, 82% among those with 2 criteria, and 90% among those with 3 or 4 criteria.

CONCLUSIONS

The sensitivity of RADT for GABHS pharyngitis is not a fixed value but varies with the severity of disease. However, even among pediatric patients with > or =3 Centor criteria for GABHS pharyngitis, the sensitivity of RADT is still too low to support the use of RADT without culture confirmation of negative results.

Pharyngitis clinical prediction rules: effect of interobserver agreement: a MetroNet study

OBJECTIVE

Pharyngitis clinical prediction rules improve Group A beta-hemolytic streptococcus (GABHS) diagnosis and decrease unnecessary antibiotic use, yet few studies have addressed clinician variability in assessment of sore throat signs and symptoms.

STUDY DESIGN AND SETTING

We conducted a cross-sectional study in which two clinicians examined each of 200 adult sore throat patients. Each patient had a rapid GABHS antigen test. Clinicians were blinded to each other's assessment and to the rapid antigen result. Interobserver agreement was estimated using a kappa coefficient. Effect of agreement on sensitivity, specificity, and hypothetic rapid antigen testing and antibiotic prescribing was determined for two clinical prediction rules.

RESULTS

We found moderate inter-rater reliability on sore throat history and physical assessments. Clinician agreement was associated with significantly fewer hypothetic rapid antigen tests performed.

CONCLUSION

Interobserver agreement enhances the utility of pharyngitis clinical prediction rules. Medical school and residency training should focus on correct assessment of history and physical examination components used in GABHS clinical prediction rules. Correct assessment will result in less GABHS testing and antibiotic prescriptions for sore throat patients.

Rapid Detection and Diagnosis of Group A Streptococcal Pharyngitis

This article reviews techniques of rapid testing and the effective diagnosis of streptococcal pharyngitis. Despite 50 years' study of streptococcal pharyngitis and 20 years' experience with rapid tests for its diagnosis, the subject continues to evolve. Rapid diagnostic tests have become more sensitive. Experts now consider not if but when they may replace throat cultures. Highly accurate rapid tests will still challenge clinicians to screen the right patients. The improvement of clinical diagnosis will require an understanding of the clinical spectrum of pharyngitis and questions relating to disease prevalence, test performance, and medical decision making. Implications for diagnostic strategies are discussed.

Penicillin for acute sore throat in children: randomised, double blind trial

OBJECTIVE

To assess the effectiveness of penicillin for three days and treatment for seven days compared with placebo in resolving symptoms in children with sore throat.

DESIGN

Randomised, double blind, placebo controlled trial.

SETTING

43 family practices in the Netherlands.

PARTICIPANTS

156 children aged 4-15 who had a sore throat for less than seven days and at least two of the four Centor criteria (history of fever, absence of cough, swollen tender anterior cervical lymph nodes, and tonsillar exudate). Interventions Patients were randomly assigned to penicillin for seven days, penicillin for three days followed by placebo for four days, or placebo for seven days.

MAIN OUTCOME MEASURES

Duration of symptoms, mean consumption of analgesics, number of days of absence from school, occurrence of streptococcal sequelae, eradication of the initial pathogen, and recurrences of sore throat after six months.

RESULTS

Penicillin treatment was not more beneficial than placebo in resolving symptoms of sore throat, neither in the total group nor in the 96 children with group A streptococci. In the groups randomised to seven days of penicillin, three days of penicillin, or placebo, one, two, and eight children, respectively, experienced a streptococcal sequela.

CONCLUSION

Penicillin treatment had no beneficial effect in children with sore throat on the average duration of symptoms. Penicillin may, however, reduce streptococcal sequelae.

Validation and modification of streptococcal pharyngitis clinical prediction rules

OBJECTIVE

To validate a simplified version of the Walsh clinical prediction rules (CPRs) for the presence of streptococcal pharyngitis in an inner-city, ethnically diverse population.

PATIENTS AND METHODS

This prospective study conducted in New York City, NY, from January 1,1997, to May 31,1997, consisted of 171 consecutive adult walk-in patients who presented with symptoms of upper respiratory tract infection and/or sore throat. The patients were assessed by using 5 clinical factors: cough, exposure to known streptococcal contact, temperature, tonsillar-pharyngeal exudates, and cervical lymphadenopathy. Throat cultures for group A beta-hemolytic streptococcus were obtained from all patients. Clinicians assessing the patients were unaware of throat culture results, and those processing the throat cultures were blinded to the clinical predictors.

RESULTS

The prevalence of streptococcal pharyngitis was 24% (95% confidence interval, 18%-30%). The simplified version of the Walsh CPR for streptococcal pharyngitis predicted accurately the probability of a positive culture in our diverse population (area under the receiver operating characteristic curve, 0.71). The simplified CPR also showed clinically useful likelihood ratios and posterior probabilities.

CONCLUSION

A simplified version of the Walsh CPR is accurate for diagnosing streptococcal pharyngitis in an inner-city population. This finding should provide clinicians more confidence in applying the CPR in similar clinical settings.

Why do general practitioners prescribe antibiotics for sore throat? Grounded theory interview study

OBJECTIVES

To understand why general practitioners prescribe antibiotics for some cases of sore throat and to explore the factors that influence their prescribing.

DESIGN

Grounded theory interview study.

SETTING

General practice.

PARTICIPANTS

40 general practitioners: 25 in the maximum variety sample and 15 in the theoretical sample.

RESULTS

General practitioners are uncertain which patients will benefit from antibiotics but prescribe for sicker patients and for patients from socioeconomically deprived backgrounds because of concerns about complications. They are also more likely to prescribe in pressured clinical contexts. Doctors are mostly comfortable with their prescribing decisions and are not prescribing to maintain the doctor-patient relationship.

CONCLUSIONS

General practitioners have reduced prescribing for sore throat in response to research and policy initiatives. Further interventions to reduce prescribing would need to improve identification of patients at risk of complications and be workable in busy clinical situations.

A critical assessment of published guidelines and other decision-support systems for the antibiotic treatment of community-acquired respiratory tract infections

Guidelines are an important means by which professional associations and governments have sought to improve the quality and cost-effectiveness of disease management for infectious diseases. Prescribing of initial antibiotic therapy for community-acquired respiratory tract infections (RTIs) is primarily empiric and physicians may often have a limited appreciation of bacterial resistance. Recent guidelines for managing RTIs have adopted a more evidence-based approach. This process has highlighted important gaps in the existing knowledge base, e.g. concerning the impact of resistance on the effectiveness of oral antibiotics for outpatient community-acquired pneumonia and the level of resistance that should prompt a change in empiric prescribing. In upper RTIs, the challenge is to identify patients in whom antibiotic therapy is warranted. Concentrated, sustained efforts are needed to secure physicians' use of guidelines. The information should be distilled into a simple format available at the point of prescribing and supported by other behavioral change techniques (e.g. educational outreach visits). Advances in information technology offer the promise of more dynamic, computer-assisted forms of guidance. Thus, RTI prescribing guidelines and other prescribing support systems should help control bacterial resistance in the community. However, their effect on resistance patterns is largely unknown and there is an urgent need for collaborative research in this area. Rapid, cost-effective diagnostic techniques are also required and new antibiotics will continue to have a role in disease management.

Treatment of sore throat in light of the Cochrane verdict: is the jury still out?

There are few good-quality studies of the effectiveness of antibiotic treatment of proven group A streptococcal (GAS) pharyngitis in children; available data suggest that antibiotics may reduce symptom duration. While there is limited justification for antibiotic treatment of GAS pharyngitis to prevent acute rheumatic fever in non-Indigenous Australians, there is no justification for routine antibiotic treatment of all patients with sore throat. Two strategies are open to clinicians: not to treat GAS pharyngitis with antibiotics, in which case no investigations should be done; or to treat cases of sore throat with clinical features that suggest GAS, in which case diagnosis should be confirmed with a throat swab, and penicillin started while awaiting the result. Penicillin should be discontinued if the swab is negative, or continued for 10 days if it is positive for GAS. Surveillance of GAS infections and acute rheumatic fever is needed in Australia, as are further studies of effectiveness (including cost-effectiveness) of antibiotic treatment of proven GAS pharyngitis.

Diagnosis of strep throat in adults: are clinical criteria really good enough?

The clinical manifestations of group A streptococcal and nonstreptococcal pharyngitis overlap quite broadly. For this reason, the updated Infectious Diseases Society of America practice guideline for group A streptococcal pharyngitis, published in this issue of Clinical Infectious Diseases, recommends laboratory confirmation of the clinical diagnosis by means of either throat culture or a rapid antigen detection test. However, a recently published guideline, developed by a subcommittee of the American College of Physicians-American Society of Internal Medicine (ACP-ASIM) in collaboration with the Centers for Disease Control and Prevention, advocates use of a clinical algorithm alone, in lieu of microbiologic testing, for confirmation of the diagnosis in adults for whom the suspicion of streptococcal infection is high. In this discussion, we examine the assumptions of the ACP-ASIM guideline, question whether its recommendations will achieve the stated objective of dramatically decreasing excess antibiotic use, and suggest that its recommendations be confirmed by clinical trials before clinicians abandon long-held teachings regarding diagnosis and management of group A streptococcal pharyngitis.

The relationship between the clinical features of pharyngitis and the sensitivity of a rapid antigen test: evidence of spectrum bias

STUDY OBJECTIVE

We evaluate the test characteristics and test for spectrum bias of a rapid antigen test for group A beta-hemolytic streptococcal (GABHS) pharyngitis among adults.

METHODS

Medical record and laboratory results of consecutive adult patients receiving a rapid antigen test for GABHS in the emergency department or urgent care clinic of an urban teaching hospital between August 1999 and December 1999 were analyzed. Patients were stratified according to the number of clinical features present using the following modified Centor criteria: history of fever, absence of cough, presence of pharyngeal exudate, and cervical lymphadenopathy. The sensitivity of the rapid antigen test was defined as the number of patients with positive rapid antigen test results divided by the number of patients with either positive rapid antigen test results or negative rapid antigen test results and positive throat culture results.

RESULTS

In the study sample of 498 patient visits, the prevalence of GABHS pharyngitis was 28% (95% confidence interval [CI] 24% to 32%). The prevalence of GABHS pharyngitis increased as modified Centor scores increased: 0 or 1=14%, 2=20%, 3=43%, and 4=52%. An increased number of modified Centor criteria (0 or 1, 2, 3, 4) was associated with increased rapid antigen test sensitivity (61%, 76%, 90%, and 97%, respectively) (Mantel-Haenszel trend test; P =.001).

CONCLUSION

The sensitivity of the rapid antigen test for GABHS is not a fixed value but varies with the spectrum of disease. Among adults with 3 or 4 clinical criteria for GABHS pharyngitis, further study may reveal that culture confirmation of negative rapid antigen test results are not necessary.

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.

Concordance of clinical findings and clinical judgment in the diagnosis of streptococcal pharyngitis

OBJECTIVE

It is uncertain how reliably clinicians apply clinical predictors of group A beta hemolytic streptococcal pharyngitis (GABHSP) to form a clinical impression, and how reliably this impression predicts culture results. The objective was to study clinician accuracy in diagnosing GABHSP.

METHODS

This was a prospective cohort study, conducted at an urgent care center of a major university. A convenience sample of 218 patients, aged 9-83 years, presenting with sore throat, was enrolled. Symptoms and signs of pharyngitis were documented on a standardized form; the likelihood of GABHSP was plotted on a visual analog scale; and throat culture was obtained. A comparison was then made between the clinical impression on presentation and the throat culture result.

RESULTS

Throat cultures were positive for GABHSP in 41 patients (19%). The probability of GABHSP was related to node size and tenderness, tonsillar exudate and hypertrophy, and pharyngeal erythema (p<0.05); but not throat soreness, degree of fever, or cough. A strong clinical impression of GABHSP (>50% on the visual analog scale) was associated with tonsillar exudate and hypertrophy, tender nodes, and pharyngeal erythema. Together, these four predictors had a sensitivity of 71%, a specificity of 77%, and a positive predictive value of 46%.

CONCLUSIONS

Clinicians in this study based their impression of GABHSP on the most reliable symptoms and signs. While a strong clinical suspicion of GABHSP predicted a greater probability of positive culture, the clinicians consistently overestimated the probability of GABHSP. Symptoms and signs predict GABHSP unreliably when used alone; they are helpful in modifying estimates of disease probability to facilitate optimal use of laboratory tests and antibiotics.