[Is streptococcal pharyngitis diagnosis possible?]. / Es posible el diagnóstico clínico de la faringoamigdalitis estreptocócica?

OBJECTIVE: To determine the validity of the Centor score (cervical adenopathy, tonsillar exudate, fever, and absence of catarrh symptoms) in diagnosing streptococcal pharyngitis (gold standard: throat swab). DESIGN: Descriptive study. SETTING: San Fernando 2 Health Centre, Madrid (outer urban area), Spain. PARTICIPANTS: On hundred forty patients over 14 years old who had a "sore throat" as main symptom and attended clinic between 14 February and 12 May, 2005. MAIN MEASUREMENTS: Sensitivity, specificity, positive and negative predictive values, and the probability quotients of the Centor score were determined. Pharyngeal throat culture was used as the reference method. RESULTS: Thirty four patients had positive throat culture (24.3%; 95% CI, 17.6%-32.4%). Finding the 4 criteria in the Centor score had a positive predictive value (PPV) of 48.1% (95% CI, 30.7%-66.0%) and a negative predictive value (NPV) of 81.4% (95% CI, 73.3%-87.5%); although only fever (OR, 3.64; 95% CI, 1.40-9.49) and tonsillar exudate (OR, 6.18; 95% CI, 2.08-18.35) were linked to streptococcal aetiology. CONCLUSIONS: The high NPV and specificity of the clinical score makes the diagnosis of non-streptococcal pharyngitis very accurate. However, the PPV is low: a high Centor score (3 or 4 criteria) does not mean streptococcal pharyngitis with certainty. What approach to take with patients suspected of streptococcal pharyngitis is not yet resolved (microbiological test, early antibiotic, or postponed antibiotic).

¿Es posible el diagnóstico clínico de la faringoamigdalitis estreptocócica? / Is streptococcal pharyngitis diagnosis possible?

Objetivo. Determinar la validez de la puntuación de Centor (adenopatías cervicales, exudado amigdalar, fiebre y ausencia de síntomas catarrales) para filiar la faringoamigdalitis de origen estreptocócico. Diseño. Estudio descriptivo. Emplazamiento. Centro de Salud San Fernando 2 (zona periurbana de Madrid). Participantes. Se incluyó a 140 pacientes mayores de 14 años que acudieron a la consulta entre el 14 de febrero y el 12 de mayo de 2005 con «dolor de garganta» como principal síntoma. Mediciones principales. Se determinaron la sensibilidad (S), la especificidad (E), los valores predictivos postivo y negativo (VPP y VPN) y los cocientes de probabilidad de la puntuación de Centor; se utilizó el frotis faríngeo como método de referencia. Resultados. En total, 34 pacientes presentaron frotis positivo (24,3%; intervalo de confianza [IC] del 95%, 17,6-32,4%). El hallazgo de los 4 criterios de Centor presentaba un VPP del 48,1% (IC del 95%, 30,7-66,0%) y un VPN del 81,4% (IC del 95%, 73,3-87,5%), aunque sólo la fiebre (odds ratio [OR] = 3,64; IC del 95%, 1,40-9,49) y el exudado amigdalar (OR = 6,18; IC del 95%, 2,08-18,35) muestran asociación con la etiología estreptocócica. Conclusiones. El sistema de puntuación clínica alcanza un alto VPN y una especificidad que permiten diagnosticar con bastante certeza las faringoamigdalitis no estreptocócicas. Sin embargo, su VPP es bajo: una puntuación alta (3 o 4 criterios) no asegura que sea una faringoamigdalitis estreptocócica. Queda por resolver qué actitud se debe adoptar ante estos pacientes con sospecha de faringitis estreptocócica: test microbiológico, antibioterapia inmediata o antibioterapia diferida

Objective. To determine the validity of the Centor score (cervical adenopathy, tonsillar exudate, fever, and absence of catarrh symptoms) in diagnosing streptococcal pharyngitis (gold standard: throat swab). Design. Descriptive study. Setting. San Fernando 2 Health Centre, Madrid (outer urban area), Spain. Participants. On hundred forty patients over 14 years old who had a "sore throat" as main symptom and attended clinic between 14 February and 12 May, 2005. Main measurements. Sensitivity, specificity, predictive values, and probability quotients of the score variables. Main measurements. Sensitivity, specificity, positive and negative predictive values, and the probability quotients of the Centor score were determined. Pharyngeal throat culture was used as the reference method. Results. Thirty four patients had positive throat culture (24.3%; 95% CI, 17.6%-32.4%). Finding the 4 criteria in the Centor score had a positive predictive value (PPV) of 48.1% (95% CI, 30.7%-66.0%) and a negative predictive value (NPV) of 81.4% (95% CI, 73.3%-87.5%); although only fever (OR, 3.64; 95% CI, 1.40-9.49) and tonsillar exudate (OR, 6.18; 95% CI, 2.08-18.35) were linked to streptococcal aetiology. Conclusions. The high NPV and specificity of the clinical score makes the diagnosis of non-streptococcal pharyngitis very accurate. However, the PPV is low: a high Centor score (3 or 4 criteria) does not mean streptococcal pharyngitis with certainty. What approach to take with patients suspected of streptococcal pharyngitis is not yet resolved (microbiological test, early antibiotic, or postponed antibiotic)