The diagnosis of strep throat in adults in the emergency room

Maternal and Fetal Death following Group A Streptococcal Meningitis in Mid-Term Pregnancy

Background. Group A streptococcal (GAS) meningitis is rarely seen in the antenatal period, but it is associated with significant mortality. We present a case of a mid-trimester woman who developed fulminant meningitis following a rapid onset atypical presentation of infection with this organism. Case. A multiparous 23(+5)-week woman presented with a 10-day history of a non-productive cough associated with pyrexia. Within minutes of her admission she collapsed and lost consciousness; sepsis was suspected and cross-specialty care was initiated. She was managed empirically in extremis with broad-spectrum antibiotics and mannitol with 3% hypertonic saline for suspected infection and raised intracranial pressure, respectively. Despite intensivist management, a CT head revealed diffuse oedema with coning of the cerebellar tonsils. Brainstem death was certified within 19 hours of admission and fetal death ensued. Postmortem bacteriology confirmed GAS meningitis. Conclusion. Through raising awareness of this patient and her disease course, we hope that future policy decisions, primary care, and hospital level management will be informed accordingly for treatment of pregnant women with suspected GAS infection.

Clinical prediction rules in practice: review of clinical guidelines and survey of GPs

BACKGROUND

The publication of clinical prediction rules (CPRs) studies has risen significantly. It is unclear if this reflects increasing usage of these tools in clinical practice or how this may vary across clinical areas.

AIM

To review clinical guidelines in selected areas and survey GPs in order to explore CPR usefulness in the opinion of experts and use at the point of care.

DESIGN AND SETTING

A review of clinical guidelines and survey of UK GPs.

METHOD

Clinical guidelines in eight clinical domains with published CPRs were reviewed for recommendations to use CPRs including primary prevention of cardiovascular disease, transient ischaemic attack (TIA) and stroke, diabetes mellitus, fracture risk assessment in osteoporosis, lower limb fractures, breast cancer, depression, and acute infections in childhood. An online survey of 401 UK GPs was also conducted.

RESULTS

Guideline review: Of 7637 records screened by title and/or abstract, 243 clinical guidelines met inclusion criteria. CPRs were most commonly recommended in guidelines regarding primary prevention of cardiovascular disease (67%) and depression (67%). There was little consensus across various clinical guidelines as to which CPR to use preferentially.

SURVEY

Of 401 responders to the GP survey, most were aware of and applied named CPRs in the clinical areas of cardiovascular disease and depression. The commonest reasons for using CPRs were to guide management and conform to local policy requirements.

CONCLUSION

GPs use CPRs to guide management but also to comply with local policy requirements. Future research could focus on which clinical areas clinicians would most benefit from CPRs and promoting the use of robust, externally validated CPRs.

Are procalcitonin or other infection markers useful in the detection of group A streptococcal acute tonsillitis?

BACKGROUND

The Centor criteria and the streptococcal rapid antigen detection test (RADT) are commonly used to differentiate sore throat patients with group A streptococci (GAS) from patients with other pathogens. We aimed to investigate if procalcitonin (PCT), C-reactive protein (CRP), white blood cell count (WBC), and absolute neutrophil count (ANC) could increase the diagnostic accuracy when added to the Centor score and RADT, or be used instead of the RADT, in the differential diagnosis.

METHODS

A 6-month prospective study was carried out in a Danish general practice with 8 physicians. One hundred acute tonsillitis patients aged 15 to 40 y were included.

RESULTS

The prevalence of GAS was 26%. The sensitivity (90%) and specificity (97%) of the RADT were high. Mean values of CRP, WBC, and ANC were significantly higher in patients with GAS compared to non-GAS patients (p < 0.001). However, the sensitivities (66-90%) and specificities (45-75%) were low. No difference in PCT levels was found (p = 0.334). CRP was the most reliable infection marker (sensitivity 90% and specificity 45%) for GAS aetiology.

CONCLUSIONS

The sensitivity, specificity, and area under the curve of the RADT were higher than those of the 4 measured infection markers in the differentiation between GAS and non-GAS acute tonsillitis patients. The infection markers did not increase the diagnostic accuracy when added to the Centor score and RADT. When RADT is not available, measurement of CRP or ANC may increase the diagnostic accuracy in the detection of GAS-positive patients.

Incidence and microbiology of peritonsillar abscess: the influence of season, age, and gender

To explore the correlations among the incidence, microbiology, season, gender, and age in patients with peritonsillar abscess (PTA) in order to identify risk factors for PTA development. All patients with PTA treated at private ENT practices in Aarhus County and in the Ear-Nose-Throat Departments at Aarhus University Hospital and Randers Hospital from January 2001 to December 2006 were included in the study. Age- and gender-stratified population data for Aarhus County for the same 6 years were obtained. The incidence rate of PTA increased from childhood to peak in teenage life and declined afterward gradually until old age. Girls predominated over boys until the age of 14 years. Subsequently, men were more frequently affected than women. Fusobacterium necrophorum (FN) was significantly more prevalent than group A Streptococcus (GAS) among patients aged 15-24 years (P < 0.001). In contrast, GAS was significantly more frequently recovered among children aged 0-9 years and adults aged 30-39 years compared with FN (P < 0.001 and P = 0.017 respectively). The seasonal variation of PTA was statistically insignificant (P = 0.437). However, GAS was significantly more frequently recovered in the winter and spring than in the summer (P = 0.002 and P = 0.036 respectively). There was a trend toward a higher incidence of FN infection during the summer than the winter (P = 0.165). Although the collected PTA incidence was stable throughout the year, the microbiology fluctuated with seasons. Patients aged 15-24 years are at an increased risk of PTA due to FN, which may have clinical implications for the diagnostic work-up and treatment of patients with acute tonsillitis.

Antibiotic prescription strategies for acute sore throat: a prospective observational cohort study

BACKGROUND

Data from trials suggest that antibiotics reduce the risk of complications of sore throat by at least 50%, but few trials for complications have been done in modern settings, and datasets of delayed antibiotic prescription are underpowered. Observational evidence is important in view of poor compliance with antibiotic treatment outside trials, but no prospective observational cohort studies have been done to date.

METHODS

We generated a large prospective cohort from the DESCARTE study, and the PRISM component of DESCARTE, of 12,829 adults presenting with sore throat (≤ 2 weeks duration) in primary care. Our follow-up of the cohort was based on a detailed and structured review of routine medical records, and analysis of the comparison of three antibiotic prescription strategies (no antibiotic prescription, immediate antibiotic prescription, and delayed antibiotic prescription) to control for the propensity to prescribe antibiotics. Information about antibiotic prescription was recorded in 12,677 individuals (4805 prescribed no antibiotics, 6088 prescribed antibiotics immediately, and 1784 prescribed delayed antibiotics). We documented by review of patients' notes (n=11,950) the development of suppurative complications (eg, quinsy, impetigo and cellulitis, otitis media, and sinusitis) or reconsultation with new or non-resolving symptoms). We used multivariate analysis to control for variables significantly related to the propensity to prescribe antibiotics and for clustering by general practitioner.

FINDINGS

164 (1.4%) of the 11,950 patients with information available developed complications; otitis media and sinusitis were the most common complications (101 patients [62%]). Compared with no antibiotic prescription, immediate antibiotic prescription was associated with fewer complications (adjusted risk ratio [RR] 0.62, 95% CI 0.43-0.91, estimated number needed to treat [NNT 193) as was delayed prescription of antibiotics (0.58, 0.34-0.98; NNT 174). 1787 of the 11,950 patients (15%) reconsulted with new or non-resolving symptoms; the risk of reconsultation was also reduced by immediate (0.83, 0.73-0.94; NNT 40) or delayed antibiotics (0.61, 0.50-0.74; NNT 18).

INTERPRETATION

Suppurative complications are not common in primary care and most are not serious. The risks of suppurative complications or reconsultation in adults are reduced by antibiotics, but not as much as the trial evidence suggests. In most cases, no antibiotic is needed, but a delayed prescription strategy is likely to provide similar benefits to an immediate antibiotic prescription.

Rapid antigen detection testing in diagnosing group A β-hemolytic streptococcal pharyngitis

Group A beta-hemolytic streptococcus (GABHS) is the most common bacterial cause of acute pharyngitis. Clinical criteria alone are not reliable enough to diagnose GABHS pharyngitis. Microbiological-testing is required for correct diagnosis. Although a throat swab culture remains the gold standard for documenting the presence of GABHS, a significant disadvantage of the culture is the delayed time of 1-2 days to obtain results. Most rapid antigen detection tests can provide results in less than 15 min. Rapid identification and treatment of patients with GABHS pharyngitis can reduce the risk of the spread of disease, may shorten the duration of symptoms, decrease the incidence of suppurative complications, decrease the amount of time lost from school/work, decrease the inappropriate use of antibiotics, reduce patient/parent dissatisfaction and alleviate the need for costly follow-up visits. All rapid antigen detection tests involve extraction of the group-specific carbohydrate antigen from the GABHS cell wall and identification of the antigen by an immunological reaction. There are numerous rapid antigen detection testing methods, namely latex agglutination, enzyme immunoassay, optical immunoassay, chemiluminescent DNA probes and PCR methods. Most of the rapid antigen detection tests that are currently in use have an excellent specificity of greater than 95% and a sensitivity of greater than or equal to 90%. Owing to the high specificity of the rapid antigen detection tests, a positive rapid antigen detection test is accepted as adequate for the diagnosis of GABHS pharyngitis. Conversely, confirmation of a negative antigen detection test with a throat culture result is necessary, unless the physician has ascertained in his/her practice that the sensitivity of the rapid antigen test used is comparable with that of a throat culture.

Incidence and clinical variables associated with streptococcal throat infections: a prospective diagnostic cohort study

BACKGROUND

Management of pharyngitis is commonly based on features which are thought to be associated with Lancefield group A beta-haemolytic streptococci (GABHS) but it is debatable which features best predict GABHS. Non-group A strains share major virulence factors with group A, but it is unclear how commonly they present and whether their presentation differs.

AIM

To assess the incidence and clinical variables associated with streptococcal infections.

DESIGN AND SETTING

Prospective diagnostic cohort study in UK primary care.

METHOD

The presence of pathogenic streptococci from throat swabs was assessed among patients aged ≥5 years presenting with acute sore throat.

RESULTS

Pathogenic streptococci were found in 204/597 patients (34%, 95% CI = 31 to 38%): 33% (68/204) were non-group A streptococci, mostly C (n = 29), G (n = 18) and B (n = 17); rarely D (n = 3) and Streptococcus pneumoniae (n = 1). Patients presented with similar features whether the streptococci were group A or non-group A. The features best predicting A, C or G beta-haemolytic streptococci were patient's assessment of severity (odds ratio [OR] for a bad sore throat 3.31, 95% CI = 1.24 to 8.83); doctors' assessment of severity (severely inflamed tonsils OR 2.28, 95% CI = 1.39 to 3.74); absence of a bad cough (OR 2.73, 95% CI = 1.56 to 4.76), absence of a coryza (OR 1.54, 95% CI = 0.99 to 2.41); and moderately bad or worse muscle aches (OR 2.20, 95% CI = 1.41 to 3.42).

CONCLUSION

Non-group A strains commonly cause streptococcal sore throats, and present with similar symptomatic clinical features to group A streptococci. The best features to predict streptococcal sore throat presenting in primary care deserve revisiting.

Predictors of suppurative complications for acute sore throat in primary care: prospective clinical cohort study

OBJECTIVE

To document whether elements of a structured history and examination predict adverse outcome of acute sore throat.

DESIGN

Prospective clinical cohort.

SETTING

Primary care.

PARTICIPANTS

14,610 adults with acute sore throat (≤ 2 weeks' duration).

MAIN OUTCOME MEASURES

Common suppurative complications (quinsy or peritonsillar abscess, otitis media, sinusitis, impetigo or cellulitis) and reconsultation with new or unresolving symptoms within one month.

RESULTS

Complications were assessed reliably (inter-rater κ=0.95). 1.3% (177/13,445) of participants developed complications overall and 14.2% (1889/13,288) reconsulted with new or unresolving symptoms. Independent predictors of complications were severe tonsillar inflammation (documented among 13.0% (1652/12,717); odds ratio 1.92, 95% confidence interval 1.28 to 2.89) and severe earache (5% (667/13,323); 3.02, 1.91 to 4.76), but the model including both variables had modest prognostic utility (bootstrapped area under the receiver operator curve 0.61, 0.57 to 0.65), and 70% of complications (124/177) occurred when neither was present. Clinical prediction rules for bacterial infection (Centor criteria and FeverPAIN) also predicted complications, but predictive values were also poor and most complications occurred with low scores (67% (118/175) scoring ≤ 2 for Centor; 126/173 (73%) scoring ≤ 2 for FeverPAIN). Previous medical problems, sex, temperature, and muscle aches were independently but weakly associated with reconsultation with new or unresolving symptoms.

CONCLUSION

Important suppurative complications after an episode of acute sore throat in primary care are uncommon. History and examination and scores to predict bacterial infection cannot usefully identify those who will develop complications. Clinicians will need to rely on strategies such as safety netting or delayed prescription in managing the uncertainty and low risk of complications.

Participatory medicine: A home score for streptococcal pharyngitis enabled by real-time biosurveillance: a cohort study

BACKGROUND

Consensus guidelines recommend against testing or treating adults at low risk for group A streptococcal (GAS) pharyngitis.

OBJECTIVE

To help patients decide when to visit a clinician for the evaluation of sore throat.

DESIGN

Retrospective cohort study.

SETTING

A national chain of retail health clinics.

PATIENTS

71 776 patients aged 15 years or older with pharyngitis who visited a clinic from September 2006 to December 2008.

MEASUREMENTS

The authors created a score using information from patient-reported clinical variables plus the incidence of local disease and compared it with the Centor score and other traditional scores that require clinician-elicited signs.

RESULTS

If patients aged 15 years or older with sore throat did not visit a clinician when the new score estimated the likelihood of GAS pharyngitis to be less than 10% instead of having clinicians manage their symptoms following guidelines that use the Centor score, 230 000 visits would be avoided in the United States each year and 8500 patients with GAS pharyngitis who would have received antibiotics would not be treated with them.

LIMITATION

Real-time information about the local incidence of GAS pharyngitis, which is necessary to calculate the new score, is not currently available.

CONCLUSION

A patient-driven approach to pharyngitis diagnosis that uses this new score could save hundreds of thousands of visits annually by identifying patients at home who are unlikely to require testing or treatment.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention and the National Library of Medicine, National Institutes of Health.

Factors associated with prelacteal feeding and timely initiation of breastfeeding in hospital-delivered infants in India

BACKGROUND

Early initiation of breastfeeding continues to remain uncommon in India, and the practice of giving prelacteal feeding is still prevalent.

OBJECTIVES

We determined the rates of timely initiation of breastfeeeding and prelacteal feeding, factors associated with these practices, and the association between the 2.

METHODS

Five hundred women who delivered live infants at a tertiary care hospital in India were included. The study outcomes were timely initiation of breastfeeding and prelacteal feeding. Multiple logistic regression was used to estimate the odds ratios (OR) of both timely initiation and prelacteal feeding.

RESULTS

Timely initiation and prelacteal feeding rates were 36.4% and 16.9%, respectively. Factors associated with timely initiation were higher maternal education (adjusted OR 2.00, 95% confidence interval [CI] 1.10, 3.60), counseling on breastfeeding during antenatal visits (adjusted OR 3.60, 95% CI 2.00, 6.20); absence of obstetric problems (adjusted OR 3.48, 95% CI 1.68, 7.23); vaginal deliveries (adjusted OR 37.57, 95% CI 17.40, 81.11); and increasing gestational age of newborn (adjusted OR 1.20, 95% CI 1.00, 1.40). Factors significantly associated with higher rates of prelacteal feeding were lower maternal education (adjusted OR 2.13, 95% CI 1.06, 4.35), Muslim religion (adjusted OR 2.27, 95% CI 1.18, 4.36), and delivery by cesarean section (adjusted OR 2.56, 95% CI 1.56, 4.19). There was a significant association between delayed initiation and prelacteal feeding (P < .001).

CONCLUSION

The rates of timely initiation of breastfeeding were undesirably low, and the practice of prelacteal feeding existed even in tertiary care hospitals. Identifying factors associated with these practices might be a strategy for optimizing timely initiation and discouraging prelacteal feeding in hospital-delivered babies.

Diagnosis of acute tonsillopharyngitis in primary care: a new approach for low-resource settings

BACKGROUND

Diagnosing GABHS (Group A-beta Hemolytic Streptococcus) tonsillopharyngitis by clinical scoring is a recommended approach in developed countries, but there is still much controversy for low resource settings.

AIM

We aimed to assess the impact of Centor criteria with the support of practical laboratory tests.

METHODS

We prospectively included patients complaining sore throat (N = 282). We evaluated them in terms of Centor scoring and performed white blood cell count (WBC), C-reactive protein (CRP), rapid antigen detecting test, and throat culture.

RESULTS

In GABHS cases (N = 32, 11·3%), two of the criteria were observed to be positive in more than half of the cases (N = 19, 59·3%), while 13 (40·7%) cases met three/four criteria. The specificity of having two criteria was found to be 65·5% and increased to 91·5% after including CRP and WBC.

CONCLUSION

Centor criteria could be safely used to reduce unnecessary antibiotic usage for tonsillopharyngitis in developing countries.

Clinical score and rapid antigen detection test to guide antibiotic use for sore throats: randomised controlled trial of PRISM (primary care streptococcal management)

OBJECTIVE

To determine the effect of clinical scores that predict streptococcal infection or rapid streptococcal antigen detection tests compared with delayed antibiotic prescribing.

DESIGN

Open adaptive pragmatic parallel group randomised controlled trial.

SETTING

Primary care in United Kingdom.

PATIENTS

Patients aged ≥ 3 with acute sore throat.

INTERVENTION

An internet programme randomised patients to targeted antibiotic use according to: delayed antibiotics (the comparator group for analyses), clinical score, or antigen test used according to clinical score. During the trial a preliminary streptococcal score (score 1, n=1129) was replaced by a more consistent score (score 2, n=631; features: fever during previous 24 hours; purulence; attends rapidly (within three days after onset of symptoms); inflamed tonsils; no cough/coryza (acronym FeverPAIN).

OUTCOMES

Symptom severity reported by patients on a 7 point Likert scale (mean severity of sore throat/difficulty swallowing for days two to four after the consultation (primary outcome)), duration of symptoms, use of antibiotics.

RESULTS

For score 1 there were no significant differences between groups. For score 2, symptom severity was documented in 80% (168/207 (81%) in delayed antibiotics group; 168/211 (80%) in clinical score group; 166/213 (78%) in antigen test group). Reported severity of symptoms was lower in the clinical score group (-0.33, 95% confidence interval -0.64 to -0.02; P=0.04), equivalent to one in three rating sore throat a slight versus moderate problem, with a similar reduction for the antigen test group (-0.30, -0.61 to -0.00; P=0.05). Symptoms rated moderately bad or worse resolved significantly faster in the clinical score group (hazard ratio 1.30, 95% confidence interval 1.03 to 1.63) but not the antigen test group (1.11, 0.88 to 1.40). In the delayed antibiotics group, 75/164 (46%) used antibiotics. Use of antibiotics in the clinical score group (60/161) was 29% lower (adjusted risk ratio 0.71, 95% confidence interval 0.50 to 0.95; P=0.02) and in the antigen test group (58/164) was 27% lower (0.73, 0.52 to 0.98; P=0.03). There were no significant differences in complications or reconsultations.

CONCLUSION

Targeted use of antibiotics for acute sore throat with a clinical score improves reported symptoms and reduces antibiotic use. Antigen tests used according to a clinical score provide similar benefits but with no clear advantages over a clinical score alone.

TRIAL REGISTRATION

ISRCTN32027234.

Management of acute streptococcal pharyngitis: still the subject of controversy

Although most cases of acute pharyngitis are viral in origin, antibiotics are overused in its treatment. Streptococcus pyogenes (group A streptococcus, GAS), the principal bacterial pathogen of acute sore throat, is responsible for merely 5-30% of cases. Moreover, GAS pharyngitis is currently the only commonly occurring form of acute pharyngitis for which antibiotic therapy is definitely indicated. Therefore the differentiation between GAS pharyngitis and that of viral etiology is crucial. Accordingly, scientific societies as well as respected advisory bodies in Europe and North America, issued guidelines for the management of acute pharyngitis with the aim of minimizing unnecessary antibiotic prescriptions in its treatment. The aim of this review work is to confront the state of the art in acute GAS pharyngitis diagnosis and treatment with different approaches to its management represented by current European and North American guidelines. Although based on scientific evidence, international guidelines differ substantially in opinions whether GAS pharyngitis diagnosis should be based on microbiological testing, clinical algorithm or a combination of both. On the other hand, some European guidelines consider GAS pharyngitis to be a mild, self-limiting disease that does not require a specific diagnosis or antimicrobial treatment except in high-risk patients. There is an agreement among guidelines that if antibiotic therapy is indicated, phenoxymethyl penicillin should be the drug of choice to treat GAS pharyngitis.

Detection of group a streptococcal pharyngitis by quantitative PCR

Background

Group A streptococcus (GAS) is the most common bacterial cause of sore throat. School-age children bear the highest burden of GAS pharyngitis. Accurate diagnosis is difficult: the majority of sore throats are viral in origin, culture-based identification of GAS requires 24–48 hours, and up to 15% of children are asymptomatic throat carriers of GAS. The aim of this study was to develop a quantitative polymerase chain reaction (qPCR) assay for detecting GAS pharyngitis and assess its suitability for clinical diagnosis.

Methods

Pharyngeal swabs were collected from children aged 3–18 years (n = 91) and adults (n = 36) located in the Melbourne area who presented with sore throat. Six candidate PCR assays were screened using a panel of reference isolates, and two of these assays, targeting speB and spy1258, were developed into qPCR assays. The qPCR assays were compared to standard culture-based methods for their ability to detect GAS pharyngitis. GAS isolates from culture positive swabs underwent emm-typing. Clinical data were used to calculate McIsaac scores as an indicator of disease severity.

Results

Twenty-four of the 127 samples (18.9%) were culture-positive for GAS, and all were in children (26%). The speB qPCR had 100% sensitivity and 100% specificity compared with gold-standard culture, whereas the spy1258 qPCR had 87% sensitivity and 100% specificity. Nine different emm types were found, of which emm 89, 3, and 28 were most common. Bacterial load as measured by qPCR correlated with culture load. There were no associations between symptom severity as indicated by McIsaac scores and GAS bacterial load.

Conclusions

The speB qPCR displayed high sensitivity and specificity and may be a useful tool for GAS pharyngitis diagnosis and research.

Use of an electronic health record clinical decision support tool to improve antibiotic prescribing for acute respiratory infections: the ABX-TRIP study

BACKGROUND

Antibiotics are often inappropriately prescribed for acute respiratory infections (ARIs).

OBJECTIVE

To assess the impact of a clinical decision support system (CDSS) on antibiotic prescribing for ARIs.

DESIGN

A two-phase, 27-month demonstration project.

SETTING

Nine primary care practices in PPRNet, a practice-based research network whose members use a common electronic health record (EHR).

PARTICIPANTS

Thirty-nine providers were included in the project.

INTERVENTION

A CDSS was designed as an EHR progress note template. To facilitate CDSS implementation, each practice participated in two to three site visits, sent representatives to two project meetings, and received quarterly performance reports on antibiotic prescribing for ARIs.

MAIN OUTCOME MEASURES

1) Use of antibiotics for inappropriate indications. 2) Use of broad spectrum antibiotics when inappropriate. 3) Use of antibiotics for sinusitis and bronchitis.

KEY RESULTS

The CDSS was used 38,592 times during the 27-month intervention; its use was sustained for the study duration. Use of antibiotics for encounters at which diagnoses for which antibiotics are rarely appropriate did not significantly change through the course of the study (estimated 27-month change, 1.57% [95% CI, -5.35%, 8.49%] in adults and -1.89% [95% CI, -9.03%, 5.26%] in children). However, use of broad spectrum antibiotics for ARI encounters improved significantly (estimated 27 month change, -16.30%, [95% CI, -24.81%, -7.79%] in adults and -16.30 [95%CI, -23.29%, -9.31%] in children). Prescribing for bronchitis did not change significantly, but use of broad spectrum antibiotics for sinusitis declined.

CONCLUSIONS

This multi-method intervention appears to have had a sustained impact on reducing the use of broad spectrum antibiotics for ARIs. This intervention shows promise for promoting judicious antibiotic use in primary care.

Streptococcal pharyngitis in children: a meta-analysis of clinical decision rules and their clinical variables

OBJECTIVE

To identify the best clinical decision rules (CDRs) for diagnosing group A streptococcal (GAS) pharyngitis in children. A combination of symptoms could help clinicians exclude GAS infection in children with pharyngitis.

DESIGN

Systematic review and meta-analysis of original articles involving CDRs in children. The Pubmed, OVID, Institute for Scientific and Technical Information and Cochrane databases from 1975 to 2010 were screened for articles that derived or validated a CDR on a paediatric population: 171 references were identified.

SETTING

Any reference including primary care for children with pharyngitis.

DATA EXTRACTION

The methodological quality of the articles selected was analysed according to published quality standards. A meta-analysis was performed to assess the statistical performance of the CDRs and their variables for the diagnosis of GAS pharyngitis.

PRIMARY OUTCOME MEASURE

The main criterion was a false-negative rate in the whole population not any worse than that of a rapid diagnostic test strategy for all patients (high sensitivity and low negative likelihood ratio).

RESULTS

4 derived and 12 validated CDRs for this diagnosis in children. These articles involved 10 523 children (mean age, 7 years; mean prevalence of GAS pharyngitis, 34%). No single variable was sufficient for diagnosis. Among the CDRs, that of Joachim et al had a negative likelihood ratio of 0.3 (95% CI 0.2 to 0.5), resulting in a post-test probability of 13%, which leads to 3.6% false-negative rate among low-risk patients and 10.8% overall, equivalent to rapid diagnostic tests in some studies.

CONCLUSIONS

The rule of Joachim et al could be useful for clinicians who do not use rapid diagnostic tests and should allow avoiding antibiotic treatment for the 35% of children identified by the rule as not having GAS pharyngitis. Owing to its poor specificity, such CDR should be used to focus rapid diagnostic tests to children with high risk of GAS pharyngitis to reduce the antibiotic consumption.

Impact of a clinical decision support system on antibiotic prescribing for acute respiratory infections in primary care: quasi-experimental trial

OBJECTIVE

To assess the effect of a clinical decision support system (CDSS) integrated into an electronic health record (EHR) on antibiotic prescribing for acute respiratory infections (ARIs) in primary care.

MATERIALS AND METHODS

Quasi-experimental design with nine intervention practices and 61 control practices in the Practice Partner Research Network, a network of practices which all use the same EHR (Practice Partner). The nine intervention practices were located in nine US states. The design included a 3-month baseline data collection period (October through December 2009) before the introduction of the intervention and 15 months of follow-up (January 2010 through March 2011). The main outcome measures were the prescribing of antibiotics in ARI episodes for which antibiotics are inappropriate and prescribing of broad-spectrum antibiotics in all ARI episodes.

RESULTS

In adult patients, prescribing of antibiotics in ARI episodes where antibiotics are inappropriate declined more (-0.6%) among intervention practices than in control practices (+4.2%) (p=0.03). However, among adults, the CDSS intervention improved prescribing of broad-spectrum antibiotics, with a decline of 16.6% among intervention practices versus an increase of 1.1% in control practices (p<0.0001). A similar effect on broad-spectrum antibiotic prescribing was found in pediatric patients with a decline of 19.7% among intervention practices versus an increase of 0.9% in control practices (p<0.0001).

CONCLUSIONS

A CDSS embedded in an EHR had a modest effect in changing prescribing for adults where antibiotics were inappropriate but had a substantial impact on changing the overall prescribing of broad-spectrum antibiotics among pediatric and adult patients.

Emergency evaluation and management of the sore throat

Although sore throat is a very common complaint in the emergency department and is often associated with benign conditions, such as pharyngitis, it can be the early onset of something much more serious and even life threatening. A thorough history and examination are vital to the correct diagnosis but a high index of suspicion must be maintained to diagnose less common but serious pathology, such as epiglottitis and retropharyngeal abscess. Airway management is paramount to survival, and aggressive means should be taken early when epiglottitis is considered.

Derivation of a clinical risk score for traumatic orbital fracture

BACKGROUND

Given that orbital fractures are found in only one of every eight patients receiving computed tomography for acute orbital trauma, we sought to prospectively identify clinical predictors of orbital fracture that may obviate the need for exposing low-risk patients to ionizing radiation.

METHODS

Prospective cohort study conducted from July 2007 through October 2009 at two urban emergency departments. Consecutive patients undergoing computed tomography for acute blunt orbital trauma were evaluated on 15 clinical findings before imaging. The primary outcome of interest was presence of any acute orbital fracture. The secondary outcome was a fracture requiring emergent operative intervention. Multivariable logistic regression analysis with multiple imputation was used to derive a predictive risk score.

RESULTS

A total of 2,262 patients with acute orbital trauma were enrolled. Median age was 38 years with male predominance (68.3%). Acute orbital fractures were found in 360 patients (15.9%). The derived risk score included orbital rim tenderness, periorbital emphysema, subconjunctival hemorrhage, pain with extraocular movement, impaired extraocular movement, and epistaxis. Across 10 multiply imputed data sets, a mean of 660 patients (29.2%) lacked all six equally weighted predictors, of which 6.3% (95% confidence interval, 4.3-8.2) experienced an acute orbital fracture and only 0.5% (95% confidence interval, 0.0-1.0) required emergent operative intervention.

CONCLUSION

Six clinical predictors identify patients with blunt orbital trauma at increased risk for acute orbital fracture. A risk score of 0 identifies patients at very low risk for emergent operative intervention. Multicenter studies are needed to validate these findings and derive a clinical decision instrument to reduce orbital imaging without compromising patient safety.

LEVEL OF EVIDENCE

Diagnostic study, level II.

A review on the mechanism of sore throat in tonsillitis

BACKGROUND

Sore throat is a common condition associated with acute upper respiratory tract infection, and recurrent episodes of infection may result in chronic tonsillitis. The current UK and USA guidelines for tonsillectomy use the incidence of sore throat episodes as an indication for surgery. However, the mechanism of sore throat is poorly described in the literature.

OBJECTIVES

This review will provide basic information for the clinician regarding: the causes, pathophysiology and neurophysiology of sore throat; the mechanism of inflammation; and the role of transient receptor potential ion channels as nociceptors involved in sore throat. The review will present new ideas on the mechanism of ice therapy as an analgesic for post-tonsillectomy pain, and the role of vanilloid and cold receptors.

Centor criteria in children in a paediatric emergency department: for what it is worth

INTRODUCTION

Centor criteria (fever >38.5°C, swollen, tender anterior cervical lymph nodes, tonsillar exudate and absence of cough) are an algorithm to assess the probability of group A β haemolytic Streptococcus (GABHS) as the origin of sore throat, developed for adults. We wanted to evaluate the correlation between Centor criteria and presence of GABHS in children with sore throat admitted to our paediatric emergency department (PED).

DESIGN

Retrospective cohort study.

SETTING

The emergency department of a large tertiary university hospital in Brussels, with over 20 000 yearly visits for children below age 16.

PARTICIPANTS

All medical records (from 2008 to 2010) of children between ages 2 and 16, who were diagnosed with pharyngitis, tonsillitis or sore throat and having a throat swab culture for GABHS. Children with underlying chronic respiratory, cardiac, haematological or immunological diseases and children who had already received antibiotics (AB) prior to the PED consult were excluded. Only records with a full disease history were selected. Out of a total 2118 visits for sore throats, 441 met our criteria. The children were divided into two age groups, 2-5 and 5-16 years.

RESULTS

The prevalence of GABHS was higher in the older children compared to the preschoolers (38.7 vs 27.6; p=0.01), and the overall prevalence was 32%. There was no significant difference in the prevalence of GABHS for all different Centor scores within an age group. Likelihood ratios (LR) demonstrate that none of the individual symptoms or a Centor score of ≥3 seems to be effective in ruling in or ruling out GABHS. Pooled LR (CI) for Centor ≥3 was 0.67 (CI 0.50 to 0.90) for the preschoolers and 1.37 (CI 1.04 to 1.79) for the older children.

CONCLUSIONS

Our results confirm the ineffectiveness of Centor criteria as a predicting factor for finding GABHS in a throat swab culture in children.

Over prescription of antibiotics for adult pharyngitis is prevalent in developing countries but can be reduced using McIsaac modification of Centor scores: a cross-sectional study

BACKGROUND

Although Group A beta hemolytic streptococcus (GABHS) can cause bacterial pharyngitis, the most common etiology is viral; despite this viral etiology, antibiotics are commonly prescribed for this infection in industrialized countries. We investigated the prevalence of GABHS in adult pharyngitis patients from lower socioeconomic settings in Karachi, Pakistan, how often antibiotics are prescribed for pharyngitis and if appropriate agents were used in a developing world setting. Finally, we wanted to see the usefulness of modified McIsaac scores in predicting positive cultures.

METHODS

Adult patients were recruited from three local hospital outpatient dispensaries (OPDs). All patients aged 14-65 years who were suspected of having bacterial pharyngitis had throat swabs taken. Laboratory results for GABHS pharyngitis were then compared with their prescriptions. Appropriateness (using the World Health Organization's definition) and type of antibiotic prescribed were assessed.

RESULTS

Of 137 patients, 30 patients each were studied for scores of 0, 1, 2 and 3; 17 patients were studied for score 4. Although 6 (4.4%) patients were GABHS+, for a prevalence of 43.8 per 1000 population, antibiotics were prescribed to 135 patients (98.5%). Of these, only 11.1% received appropriate antibiotics while 88.9% received inappropriate antibiotics. Penicillins were prescribed most (34.1%), especially amoxicillin/clavulanate; followed by macrolides (31.1%), especially the second-generation agents, and fluoroquinolones (14.8%). McIsaac scores were found to be 100% sensitive and 68.7% specific, giving a positive predictive value (PPV) of 12.7% and a negative predictive value (NPV) of 100%.

CONCLUSIONS

Antibiotics were prescribed irrationally to adult pharyngitis patients, as most cultures were negative for bacterial infection. McIsaac modification of Centor scores related directly to culture results. We would therefore highly recommend its use to help family physicians make treatment decisions for adult pharyngitis patients.

Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America

The guideline is intended for use by healthcare providers who care for adult and pediatric patients with group A streptococcal pharyngitis. The guideline updates the 2002 Infectious Diseases Society of America guideline and discusses diagnosis and management, and recommendations are provided regarding antibiotic choices and dosing. Penicillin or amoxicillin remain the treatments of choice, and recommendations are made for the penicillin-allergic patient, which now include clindamycin.

Large-scale validation of the Centor and McIsaac scores to predict group A streptococcal pharyngitis

BACKGROUND

The Centor and McIsaac scores guide testing and treatment for group A streptococcal (GAS) pharyngitis in patients presenting with a sore throat, but they were derived on relatively small samples. We perform a national-scale validation of the prediction models on a large, geographically diverse population.

METHODS

We analyzed data collected from 206,870 patients 3 years or older who presented with a painful throat to a United States national retail health chain from September 1, 2006, to December 1, 2008. Main outcome measures were the proportions of patients testing positive for GAS pharyngitis according to the Centor and McIsaac scores (both scales, 0-4).

RESULTS

For patients 15 years or older, 23% (95% CI, 22%-23%) tested positive for GAS, including 7% (95% CI, 7%-8%) of those with a Centor score of 0; 12% (95% CI, 11%-12%) of those with a Centor score of 1; 21% (95% CI, 21%-22%) of those with a Centor score of 2; 38% (95% CI, 38%-39%) of those with a Centor score of 3; and 57% (95% CI, 56%-58%) of those with a Centor score of 4. For patients 3 years or older, 27% (95% CI, 27%-27%) tested positive for GAS, including 8% (95% CI, 8%-9%) of those testing positive with aMcIsaac score of 0; 14% (95% CI, 13%-14%) of those with a McIsaac score of 1; 23% (95% CI, 23%-23%) of those with a McIsaac score of 2; 37% (95% CI, 37%-37%) of those with a McIsaac score of 3; and 55% (95% CI, 55%-56%) of those with a McIsaac score of 4. The 95% CIs overlapped between our retail health chain–derived probabilities and the prior reports.

CONCLUSION

Our study validates the Centor and McIsaac scores and more precisely classifies risk of GAS infection among patients presenting with a painful throat to a retail health chain.

In primary health care, never prescribe antibiotics to patients suspected of having an uncomplicated sore throat caused by group A beta-haemolytic streptococci without first confirming the presence of this bacterium

BACKGROUND

There are several consensus-describing decision rules for patients in primary health care with a sore throat. The objective of this study was to estimate the number of unnecessary antibiotic prescriptions in primary health care given to patients with a sore throat, due to these different decision rules. A further aim was to suggest revised rules for decision-making in primary health care, when a sore throat caused by group A beta-haemolytic streptococci (GAS) is suspected.

METHODS

The design was a reanalysis of previously published articles describing the prevalence of GAS and physician behaviour when treating patients with a sore throat. The risk of unnecessary antibiotic prescribing in different situations was estimated and applied to the Swedish population.

RESULTS

Introducing the rule of never prescribing antibiotics without first confirming the presence of GAS would result in an annual reduction in Sweden of 20,360-25,192 unnecessary antibiotic prescriptions in children and 65,311-98,160 in adults.

CONCLUSIONS

The single most important rule in primary health care to minimize the risk of unnecessary antibiotic prescription to patients with an uncomplicated sore throat, and where an infection with GAS is suspected, is to never prescribe antibiotics at the first visit without first confirming the presence of this bacterium. Adding more decision rules may to some extent further reduce the number of unnecessary antibiotic prescriptions.

Guideline for the management of acute sore throat

The European Society for Clinical Microbiology and Infectious Diseases established the Sore Throat Guideline Group to write an updated guideline to diagnose and treat patients with acute sore throat. In diagnosis, Centor clinical scoring system or rapid antigen test can be helpful in targeting antibiotic use. The Centor scoring system can help to identify those patients who have higher likelihood of group A streptococcal infection. In patients with high likelihood of streptococcal infections (e.g. 3-4 Centor criteria) physicians can consider the use of rapid antigen test (RAT). If RAT is performed, throat culture is not necessary after a negative RAT for the diagnosis of group A streptococci. To treat sore throat, either ibuprofen or paracetamol are recommended for relief of acute sore throat symptoms. Zinc gluconate is not recommended to be used in sore throat. There is inconsistent evidence of herbal treatments and acupuncture as treatments for sore throat. Antibiotics should not be used in patients with less severe presentation of sore throat, e.g. 0-2 Centor criteria to relieve symptoms. Modest benefits of antibiotics, which have been observed in patients with 3-4 Centor criteria, have to be weighed against side effects, the effect of antibiotics on microbiota, increased antibacterial resistance, medicalisation and costs. The prevention of suppurative complications is not a specific indication for antibiotic therapy in sore throat. If antibiotics are indicated, penicillin V, twice or three times daily for 10 days is recommended. At the present, there is no evidence enough that indicates shorter treatment length.

Streptococcus pyogenes and re-emergence of scarlet fever as a public health problem

Explosive outbreaks of infectious diseases occasionally occur without immediately obvious epidemiological or microbiological explanations. Plague, cholera and Streptococcus pyogenes infection are some of the epidemic-prone bacterial infections. Besides epidemiological and conventional microbiological methods, the next-generation gene sequencing technology permits prompt detection of genomic and transcriptomic profiles associated with invasive phenotypes. Horizontal gene transfer due to mobile genetic elements carrying virulence factors and antimicrobial resistance, or mutations associated with the two component CovRS operon are important bacterial factors conferring survival advantage or invasiveness. The high incidence of scarlet fever in children less than 10 years old suggests that the lack of protective immunity is an important host factor. A high population density, overcrowded living environment and a low yearly rainfall are environmental factors contributing to outbreak development. Inappropriate antibiotic use is not only ineffective for treatment, but may actually drive an epidemic caused by drug-resistant strains and worsen patient outcomes by increasing the bacterial density at the site of infection and inducing toxin production. Surveillance of severe S. pyogenes infection is important because it can complicate concurrent chickenpox and influenza. Concomitant outbreaks of these two latter infections with a highly virulent and drug-resistant S. pyogenes strain can be disastrous.

Adoption of a clinical decision support system to promote judicious use of antibiotics for acute respiratory infections in primary care

PURPOSE

Overuse of antibiotics for acute respiratory infections (ARIs) in primary care is an established risk factor for worsening antimicrobial resistance. The "Reducing Inappropriate Prescribing of Antibiotics by Primary Care Clinicians" study is assessing the impact of a clinical decision support system (CDSS) on antibiotic prescribing for ARIs using a multimethod intervention to facilitate CDSS adoption. The purpose of this report is to describe use of the CDSS, as well as facilitators and barriers to its adoption, during the first year of the 15-month intervention.

METHODS

Between January 1, 2010 and December 31, 2010, 39 providers in 9 practices in US states participated in this study. Quarterly EHR based audit and feedback, practice site visits for academic detailing, performance review and CDSS training, and "best-practice" dissemination during two meetings of study participants were used to facilitate CDSS adoption. Mixed methods were used to evaluate adoption of the CDSS. Using data extracted from the EHR, CDSS use for ARI was calculated. To determine facilitators and barriers of CDSS adoption, semi-structured group interviews were conducted with providers and staff at each practice.

RESULTS

During the first year of implementation, the ABX-TRIP CDSS was used 14,086 times for ARI encounters. Overall, practice use of the CDSS during ARI encounters ranged from 39.4% to 77.2%. Median use of the CDSS for adult patients was 58.2% and 68.6% for pediatric patients. Key factors associated with CDSS adoption include the perception by providers that it assists with decision making and stimulates patient discussions, engagement of non-physician staff and an iterative CDSS development process.

CONCLUSIONS

Adoption of a custom designed CDSS in the first year of implementation is promising. Successful implementation of such technology requires a focus not only on the technological solution itself, but on its integration with the entire clinical workplace.

[Use of the rapid antigen technique in the diagnosis of Streptococcus pyogenes pharyngotonsillitis]

INTRODUCTION

Streptococcus pyogenes is the most frequent bacterial cause of acute tonsillopharyngitis. The validity of the rapid antigen test was analysed for its diagnosis in a Paediatric Primary Care setting. The clinical profile with better diagnostic yield was also identified. The unnecessary use of antibiotics was quantified when the rapid antigen test or only the clinical diagnosis was used. The sensitivity of the assay to penicillin, erythromycin and clindamycin was also determined.

PATIENTS AND METHODS

Cross-sectional study was conducted on children between 2 to 14 years with acute tonsillitis and/or pharyngitis seen in five Primary Care Centres, from January 2008 to May 2010. After a clinical diagnosis, two swabs were taken for pharyngotonsillar smears: the first was used for a rapid antigen test, and the second one for a culture and a study of antibiotic sensitivity, with its analysis being blind to the rapid test result. A total sample of 546 consecutive was envisaged and with consecutive sampling.

RESULTS

A total 192 patients were included. The prevalence of Streptococcus pyogenes was 38.7% (95% CI: 31.4-45.7). Odynophagia and scarlatiniform rash were most likely with positive cultures, the Streptococcus pyogenes was sensitive to penicillin in 100%, to erythromycin in 97.3% and to clindamycin in 86.3%. The specificity of the rapid antigen test was 91.5% and with a Negative Predictive Value of 91.5%. About half (49.2%) of those who would have receive antibiotics for clinical suspicion would have been treated unnecessarily, with this decreasing to at least in 29.5% when using the rapid antigen test.

CONCLUSIONS

The rapid antigen test can lead to a better use of antibiotics. Its use in Paediatric Primary Health Care could be useful when, as when the result is negative, there would be no need to confirm by a culture, in those Health Centres with difficult access to laboratory.

Validity of a point-of-care based on heterophile antibody detection for the diagnosis of infectious mononucleosis in primary care

OBJECTIVE

To evaluate the validity of a point-of-care test to diagnose infectious mononucleosis (IM) compared with Epstein-Barr virus (EBV) specific serology.

METHODS

Patients over 14 years with sore throat and four Centor criteria--tonsillar exudate, fever, lymph glands tenderness and absence of cough--and negative pharyngeal testing for group A β-haemolytic streptococcal antigen were consecutively recruited. All patients underwent pharyngotonsillar swab for microbiological culture, the rapid OSOM MonoTest for the diagnosis of IM in whole blood, the Paul-Bunnell test and complete blood analysis with serology for EBV and cytomegalovirus the day after the visit and at 15 days. Sensitivity and specificity were determined.

RESULTS

We included 145 patients with a mean age of 24 ± 6.8 years. Of these, serology was determined in 129 subjects, with IM being diagnosed in 14 (10.9%). Both the MonoTest and the Paul-Bunnell test were positive in 13 patients with IM (92.9%) with no patient without disease being positive for either test--sensitivity of 92.9% (95% CI: 64.2-99.6%) and specificity of 100% (95% CI: 96-100%). The culture showed streptococcus A infection in 1 case (0.7%) and streptococcus C in 62 cases (42.8%). A total of 78 patients presented past infection by EBV (60.5%).

CONCLUSIONS

Only one out of 10 patients with sore throat, four Centor criteria and negative rapid test for streptococcal infection presents IM. Despite the MonoTest presenting optimum sensitivity and specificity, it was found to have the same validity as the Paul-Bunnell test, with serological study continuing to be necessary for precise diagnosis of IM.

The methods of comparative effectiveness research

This review describes methods used in comparative effectiveness research (CER). The aim of CER is to improve decisions that affect medical care at the levels of both policy and the individual. The key elements of CER are (a) head-to-head comparisons of active treatments, (b) study populations typical of day-to-day clinical practice, and (c) a focus on evidence to inform care tailored to the characteristics of individual patients. These requirements will stress the principal methods of CER: observational research, randomized trials, and decision analysis. Observational studies are especially vulnerable because they use data that directly reflect the decisions made in usual practice. CER will challenge researchers and policy makers to think deeply about how to extract more actionable information from the vast enterprise of the daily practice of medicine. Fortunately, the methods are largely applicable to research in the public health system, which should therefore benefit from the intense interest in CER.

Should a near-patient test be part of the management of pharyngitis in the pediatric emergency department?

OBJECTIVE

The study's objective was to evaluate the efficacy of a rapid streptococcal test as a single diagnostic agent in the diagnosis of streptococcal pharyngitis in patients presenting to a pediatric emergency department.

METHODS

We performed a rapid streptococcal test as part of the diagnostic workup for patients presenting with clinical findings consistent with streptococcal pharyngitis. In addition to undergoing the study intervention, each patient had a standard throat swab sent to the laboratory for formal culture. A questionnaire detailing the clinical features was to be completed in each case.

RESULTS

Two hundred ten near-patient tests were performed. Complete laboratory results were available in 177 cases (77%). Clinical data were available for analysis in 94 patients (53%). In our patient population, the near-patient test had a high specificity (98.6%) but a low sensitivity (71%). The clinical presentation of confirmed group A β-hemolytic streptococcal pharyngitis is very variable.

CONCLUSIONS

The QuickVue In-Line Strep A test for streptococcal pharyngitis is unreliable in our patient population. Clinical findings are unhelpful in confirming the diagnosis. Formal laboratory culture is the criterion standard for identifying the organism, but the results are not clinically significant in every case. Acute pharyngitis presenting to the pediatric emergency department can be managed in accordance with the recommendations in the Scottish Intercollegiate Guideline Network guideline.

[Consensus document on the diagnosis and treatment of acute tonsillopharyngitis]

Acute tonsillopharyngitis is one of the most common childhood diseases. Viruses are the most frequent origin. Group A Streptococcus (Streptococcus pyogenes) is the main bacterial cause. A culture or a rapid antigen-detection test of a throat-swab specimen should only be done on the basis of clinical scores, in order to avoid over-diagnosis of bacterial origin and unnecessary antibiotic prescription. The objectives of treatment are: the reduction of symptoms, reduce the contagious period, and prevent local suppurative and systemic complications. Ideally, only confirmed cases should receive antibiotics. If there is no possibility to perform a rapid antigen-detection test, or in some cases if the result is negative, it is recommended to perform a culture and, if there is high suspicious index, to prescribe antibiotics. Penicillin is the treatment of choice, although amoxicillin is also accepted as the first option. Amoxicillin/clavulanate is not indicated in any case as empirical treatment. Macrolides are not a first choice antibiotic, and should be reserved for those patients with immediate penicillin allergy reaction or for the treatment of streptococcal carriers. It is of primordial importance to adapt the prescribing of antibiotics to the scientific evidence.

[Guidelines for the management of sore throat from the German Society of General Practice and Family Medicine]

AIM

The aim of this guideline is to propose a diagnostic and therapeutic approach to manage sore throat in ambulatory care.

METHOD

Relevant literature on the treatment of sore throat in primary care was retrieved and evaluated. During its development, the guidelines underwent a panel test, a practice test and a consensus conference.

RECOMMENDATIONS

Sore throat is mostly a short, self-limiting infection. Accurate etiologic diagnosis is generally not possible. Routine antibiotic treatment of sore throat for the prevention of complications is currently not indicated. The effect of antibiotics on symptoms and duration of disease is, at best, moderate. It is more pronounced in patients with typical clinical symptoms and signs of pharyngitis caused by group A streptococci (GAS) and slightly more pronounced again in cases of additional positive throat swab for GAS. An algorithm for decision-making is proposed. Rapid testing for streptococcal antigen or a culture for GAS is only recommended if the result is likely to influence therapeutic decision-making. Patients with more severe illness and signs of GAS pharyngitis can be given antibiotic therapy for symptomatic relief.

Improved diagnostic accuracy of group A streptococcal pharyngitis with use of real-time biosurveillance

BACKGROUND

Clinical prediction rules do not incorporate real-time incidence data to adjust estimates of disease risk in symptomatic patients.

OBJECTIVE

To measure the value of integrating local incidence data into a clinical decision rule for diagnosing group A streptococcal (GAS) pharyngitis in patients aged 15 years or older.

DESIGN

Retrospective analysis of clinical and biosurveillance predictors of GAS pharyngitis.

SETTING

Large U.S.-based retail health chain.

PATIENTS

82 062 patient visits for pharyngitis.

MEASUREMENTS

Accuracy of the Centor score was compared with that of a biosurveillance-responsive score, which was essentially an adjusted Centor score based on real-time GAS pharyngitis information from the 14 days before a patient's visit: the recent local proportion positive (RLPP).

RESULTS

Increased RLPP correlated with the likelihood of GAS pharyngitis (r(2) = 0.79; P < 0.001). Local incidence data enhanced diagnostic models. For example, when the RLPP was greater than 0.30, managing patients with Centor scores of 1 as if the scores were 2 would identify 62, 537 previously missed patients annually while misclassifying 18, 446 patients without GAS pharyngitis. Decreasing the score of patients with Centor values of 3 by 1 point for an RLPP less than 0.20 would spare unnecessary antibiotics for 166, 616 patients while missing 18, 812 true-positive cases.

LIMITATIONS

Analyses were conducted retrospectively. Real-time regional data on GAS pharyngitis are generally not yet available to clinicians.

CONCLUSION

Incorporating live biosurveillance data into clinical guidelines for GAS pharyngitis and other communicable diseases should be considered for reducing missed cases when the contemporaneous incidence is elevated and for sparing unnecessary antibiotics when the contemporaneous incidence is low. Delivering epidemiologic data to the point of care will enable the use of real-time pretest probabilities in medical decision making.

[Prudent use of antibiotics and suggestions for improvement in the primary health care system]

A third of all primary care (PC) visits are due to infectious diseases and more than half of these are due to respiratory tract infections. In most cases, data from the clinical history and physical examinations do not help discern whether the aetiology of the infection is bacterial or not and, when in doubt, the family doctor tends to prescribe antibiotics despite the marginal effect that these drugs have on most respiratory infections. Moreover, PC physicians overestimate the proportion of patients with infections who expect to receive antibiotics and according to the scientific literature this perception is often wrong. In addition, patient expectations are often based on false assumptions or experiences from previous visits. Various strategies have proven useful in promoting more prudent use of antibiotics in PC. Delayed prescription of antibiotics is recommended mainly in non-serious infections of suspected viral aetiology in patients who express a preference for antibiotics. Improving communication skills has also proven useful in reducing prescriptions of antibiotics as has the use of rapid diagnostic tests in the doctor's office, mainly rapid antigen techniques for diagnosis of strep throat and determination of C-reactive protein. The results of the Happy Audit study recently conducted in Spain confirm these findings.

A comparison between the Strep A Rapid Test Device and conventional culture for the diagnosis of streptococcal pharyngitis

BACKGROUND

Rapid antigen detection tests are frequently used to diagnose pharyngitis due to Streptococcus pyogenes. Because a large number of kits are available commercially, performance characteristics may vary considerably. The present study evaluated one such kit currently in use in Canadian laboratories for which published evaluations are not available.

OBJECTIVE

To evaluate the performance characteristics of the Strep A Rapid Test Device (SARTD) (Nova Century Scientific Inc, Canada).

METHODS

Pharyngeal swabs from 818 patients with suspected streptococcal pharyngitis were tested. Swabs were initially inoculated onto the surface of a blood agar plate and then used to perform the rapid antigen test. The test was performed in accordance with the product monograph. Beta-hemolytic colonies were identified as S pyogenes using conventional means.

RESULTS

Four hundred ninety specimens were obtained from children and 328 from adults. S pyogenes was recovered from 171 (21%) patients. The SARTD detected S pyogenes antigens in 123 of 171 specimens from which S pyogenes was isolated on culture; the screen was negative in 610 of 647 specimens from which cultures were negative. The positive and negative predictive values of the SARTD were 76.9% and 92.7%, respectively.

CONCLUSIONS

The SARTD was much less sensitive (72%) than was suggested in the product monograph (90%). Laboratories should vigorously evaluate such products in-house, optimize specimen collection and transport, and choose more sensitive kits for use.

Predicting streptococcal pharyngitis in adults in primary care: a systematic review of the diagnostic accuracy of symptoms and signs and validation of the Centor score

BACKGROUND

Stratifying patients with a sore throat into the probability of having an underlying bacterial or viral cause may be helpful in targeting antibiotic treatment. We sought to assess the diagnostic accuracy of signs and symptoms and validate a clinical prediction rule (CPR), the Centor score, for predicting group A β-haemolytic streptococcal (GABHS) pharyngitis in adults (> 14 years of age) presenting with sore throat symptoms.

METHODS

A systematic literature search was performed up to July 2010. Studies that assessed the diagnostic accuracy of signs and symptoms and/or validated the Centor score were included. For the analysis of the diagnostic accuracy of signs and symptoms and the Centor score, studies were combined using a bivariate random effects model, while for the calibration analysis of the Centor score, a random effects model was used.

RESULTS

A total of 21 studies incorporating 4,839 patients were included in the meta-analysis on diagnostic accuracy of signs and symptoms. The results were heterogeneous and suggest that individual signs and symptoms generate only small shifts in post-test probability (range positive likelihood ratio (+LR) 1.45-2.33, -LR 0.54-0.72). As a decision rule for considering antibiotic prescribing (score ≥ 3), the Centor score has reasonable specificity (0.82, 95% CI 0.72 to 0.88) and a post-test probability of 12% to 40% based on a prior prevalence of 5% to 20%. Pooled calibration shows no significant difference between the numbers of patients predicted and observed to have GABHS pharyngitis across strata of Centor score (0-1 risk ratio (RR) 0.72, 95% CI 0.49 to 1.06; 2-3 RR 0.93, 95% CI 0.73 to 1.17; 4 RR 1.14, 95% CI 0.95 to 1.37).

CONCLUSIONS

Individual signs and symptoms are not powerful enough to discriminate GABHS pharyngitis from other types of sore throat. The Centor score is a well calibrated CPR for estimating the probability of GABHS pharyngitis. The Centor score can enhance appropriate prescribing of antibiotics, but should be used with caution in low prevalence settings of GABHS pharyngitis such as primary care.

Impact on antibiotic prescription of rapid antigen detection testing in acute pharyngitis in adults: a randomised clinical trial

BACKGROUND

Acute pharyngitis is one of the most frequent reasons for a GP consultation, and in most cases an antibiotic is prescribed.

AIM

To determine the impact of rapid antigen detection testing (RADT) to identify group A beta haemolytic streptococcus in acute pharyngitis on the utilisation of antibiotics and appropriateness of their use.

DESIGN AND SETTING

Cluster randomised controlled trial in primary care centres in Catalonia, Spain.

METHOD

Patients with acute pharyngitis aged 14 years or older with at least one Centor criterion (fever, tonsillar exudate, tender enlarged anterior cervical lymph nodes, or absence of cough) were recruited. Participant physicians were randomly assigned to one of two study arms: an intervention group (assigned to RADT) and a control group (following usual care, without RADT).

RESULTS

Of the 557 adults enrolled, 543 could be evaluated for analysis (281 [51.7%] in the intervention group and 262 [48.3%] in the control group). GPs without access to RADT were more likely to prescribe antibiotics compared with those who performed rapid tests (64.1% versus 43.8%, P<0.001). The more Centor criteria the patients presented, the greater the number of antibiotics prescribed, regardless of whether RADT was available (P<0.001). Antibiotics were prescribed in 30.7% of the cases with negative RADT results. Inappropriate antibiotic prescription was observed in 226 cases (43%), and was significantly greater in the control than in the intervention group (60% versus 26.9%; P<0.001).

CONCLUSION

Even though more than 30% of negative RADT results resulted in antibiotic prescribing, the study findings support the use of RADT in the consultation. This strategy has an important impact on reducing antibiotic prescription among adults with acute pharyngitis.