Multivariate Predictive Models for Group A Beta‐hemolytic Streptococcal Pharyngitis in Children

Abstract

Abstract. Objectives:To create predictive models for the clinical diagnosis of group A beta-hemolytic streptococcal (GABHS) pharyngitis in children. Methods: Patients aged 6 months to 18 years presenting to a pediatric ED with suspected GABHS pharyngitis were prospectively enrolled in the study. Clinicians recorded pertinent clinical information using a standardized form and obtained a throat swab to culture GABHS using a reference standard method. Twelve demographic and clinical features of patients with positive throat cultures were compared with the features of patients with negative throat cultures. Significantly different features were entered in a stepwise logistic regression analysis to create predictive models for the diagnosis. Results: Eighty-five patients (29%) were culture-positive and 212 (71%) were culture-negative for GABHS. Respective mean ages were 6.2 years and 6.1 years in the two groups. Univariate chi-square analysis of the 12 features identified six variables that were significantly associated with GABHS. All significant features were initially included in a stepwise logistic regression analysis. In model I, four independent variables were identified: moderate to severe presentation of tonsillar swelling, moderate to severe tenderness and enlargement of cervical lymph nodes, the presence of scarlatiniform rash, and the absence of moderate to severe coryza, yielding a 95% probability for GABHS. Excluding the rare scarlatiniform rash, the remaining variables were used in the second regression analysis. In model II, three independent variables were identified: moderate to severe tonsillar swelling, moderate to severe tenderness and enlargement of cervical lymph nodes, and absence of moderate to severe coryza, yielding a probability of 65% for the diagnosis. A probability of <15% was observed in the absence of scarlatiniform rash, the absence of moderate to severe tenderness and enlargement of cervical lymph nodes, and the presence of moderate to severe coryza. Conclusions: In children with moderate to severe presentation of tonsillar swelling, tenderness and enlargement of cervical lymph nodes, and the absence of coryza, the probability of a positive throat culture is >65%. Conversely, in the absence of a moderate to severe presentation of tonsillar swelling, enlargement of cervical nodes, and the presence of coryza, the probability of a positive throat culture is <15%. If prospectively validated, these models could be integrated into a consistent treat, test, and no treatment/no testing approach to the clinical management of childhood pharyngitis.

Comparação entre métodos clínicos e laboratoriais no diagnóstico das faringotonsilites estreptocócicas

“…21 Attia et al also assessed the subjective diagnostic capacity of doctors and concluded that 52% of patients without the disease would be treated and 28% of sick patients would not be offered treatment. 9 In our study the physician would treat 47% of negative patients would fail to treat 21% of the positive patients, which values are very similar to those found by Attia et al (Figure 2). These analyses are reflected in the low sensitivity, specificity and positive and negative predictive values demonstrated in Table 3.…”

“…If exanthema scarlatina is presented in its classic form it is highly indicative of bacterial disease, with a high positive predictive value, but it is, in fact, very rare. [2][3][4][5][6][7][8][9] A recent meta-analysis, including several different studies and a total of 5,453 patients, took each symptom in isolation and was unable to identify any symptom that could alone diagnose streptococcal sore throat. 8 Even a combination of signs and symptoms was unable to differentiate with certainty between viral and bacterial sore throats.…”

Clinical predictors of childhood streptococcal pharyngitis

“…Some studies abroad also indicated sore throat, tonsillar exudates, tender anterior cervical adenopathy and even high grade fever as the clinical predictors associated significantly with streptococcal pharyngitis. [28][29][30] Our study in Padang showed that tonsillar exudates and tender anterior cervical adenopathy were the strong clinical predictors and these were similar with other data from study abroad. 28,29 In our study, combination of more than two clinical predictors would increase probability of streptococcal pharyngitis (up to 99%).…”

“…There are many clinical predictors of streptococcal pharyngitis proposed in studies and new important innovations in simplifying the diagnosis, especially in places with limited facility of laboratories. 17,[28][29][30] Only a little part of clinical features of acute pharyngitis were representative for clinical predictors of streptococcal pharyngitis. In Padang it was found only four clinical predictors are representative and those are sore throat, absence of cough, tonsillar exudates and tender anterior cervical adenopathy.…”

Performance of Rapid Streptococcal Antigen Testing Varies by Personnel

“…Unfortunately, clinical findings and simple scoring systems based on these findings are unreliable for identifying patients with GAS pharyngitis (2,12,17,24,31). For this reason, laboratory tests are commonly used to confirm the diagnosis in children who present with throat pain.…”