RESUMEN

The aim of this study is to determinate the prevalence of oropharyngeal colonization by group A beta-hemolytic Streptococcus (GABHS) in pediatric population of Ponta Grossa, a midsize city of southern Brazil; estimate the effectiveness of antistreptolysin-O (ASO), compared to culture, in presence of infection; and design an unpublished investigative algorithm of rheumatic fever's suspicion, based on needs identified in worldwide consensus. It is an epidemiologic, observational and transversal study, involving 180 children younger than 12 years. Secretion of posterior oropharynx was collected for culture; and peripheral blood for determination of ASO. Student-t and chi-square tests, with Yates correction, were performed for statistical analysis. The ASO cutoff was determined by Receiver Operating Characteristic (ROC) curve. The prevalence encountered was 3.9%, and 25.5% of the children showed reagent ASO. This serological test demonstrated quantitatively and qualitatively significant associations to the GABHS presence (p=0.0001 for both associations) throughout the ROC curve, 200 U Todd was the value that resulted in the best accuracy, demonstrating 100% of sensibility and 80% of specificity in the GAS infection documentation. Also, it was found that the value of 1.200 U represents a specificity of 100%. The results emphasize the need for similar studies in other populations, to provide better targeting of the diagnosis and treatment of oropharyngitis by GABHS, which in turn can prevent up to 80% the cases of rheumatic fever, and consequently, the chronic rheumatic heart disease.

RESUMEN

La antiestreptolisina O (ASO), es empleada como método diagnóstico de infecciones por estreptococos beta hemolíticos del grupo A (EBHGA). Esta bacteria produce faringitis y amigdalitis, y puede conllevar a secuelas como la fiebre reumática y la glomerulonefritis, que pueden ser prevenidas con un diagnóstico y tratamiento oportuno. A 125 niños sanos con edades entre 6 y 9 años, del municipio Francisco Linares Alcántara, se les realizó el cultivo de exudado faríngeo y la determinación de títulos de ASO. De ellos ninguno fue portador asintomático de EBHGA, sin embargo se aisló 0,8% de estreptococos beta hemolítico del grupo C y 0,8% de estreptococos beta hemolíticos del grupo F. Por otro lado, el 88,8% de los niños presentó títulos menores de 166 Unidades Todd/mL y el 10,4% un título de 333 Unidades Todd/mL, estableciéndose este último como posible valor referencial para la población en estudio, el cual difiere del señalado por los equipos diagnósticos utilizados en el país, que son obtenidos en otros países y con muestras de adultos. Esto apoya el hecho de que se deben establecer valores referenciales para cada población, de manera que se pueda realizar un diagnóstico asertivo y precoz para evitar las posibles secuelas postestreptocócicas.

Antistreptolysin О (ASO) is used as a diagnostic method for group A beta-hemolytic streptococci (GABHS) infections. This bacterium produces pharyngitis and tonsillitis and can lead to rheumatic fever and glomerulonephritis sequelae, which can be prevented by opportune diagnosis and treatment. A group of 125 healthy children with ages between 6 and 9 years from the Francisco Linares Alcántara municipality, were tested by carrying out a throat culture and determination of ASO titers. None of them were asymptomatic GABHS carriers, nevertheless, 0.8% group C beta-hemolytic streptococci, and 0.8% group F beta-hemolytic streptococci were isolated. On the other hand, 88.8% of children presented titers under 166 Todd Units/mL and 10.4% a titers of 333 Todd Units/mL, establishing this last one as possible reference value for the study population, which differs from those of diagnostic equipments used in the country, which have values obtained from other countries and with samples from adult specimens. This supports the fact that reference values should be established for each population, so that an assertive and early diagnosis can be done, avoiding possible post-streptococci sequelae.

RESUMEN

Introducción. La glomerulonefritis aguda postestreptocócica (GNA-PE) es la causa más frecuente del síndrome nefrítico en la niñez; tiene un amplio espectro de presentación que va desde una condición asintomática hasta condiciones graves como: falla renal aguda y encefalopatía. La incidencia ha disminuido en los últimos años, aunque deficientes condiciones higiénicas pueden aumentar la prevalencia de infecciones estreptocócicas nefritogénicas, y con ello aumentar el riesgo de brotes epidémicos de glomerulonefritis aguda. La encefalopatía hipertensiva (EH) se presenta en 1 a 7% de los casos durante el curso de la enfermedad y es una complicación grave, pero que manejada adecuadamente no deja secuelas. En el diagnóstico diferencial se deben tener en cuenta eventos vasculares cerebrales, infecciones del sistema nervioso central, tumores cerebrales y alteraciones tóxico-metabólicas. Caso clínico. Se describe el caso de un escolar masculino de 10 años de edad, previamente sano, con antecedente de faringoamigdalitis en la semana previa a su atención en urgencias. Fue llevado a consulta por alteración del sensorio; cursó con un estado convulsivo parcial que cedió al aplicar diacepam endovenoso. Se detectó hipertensión arterial, hematuria y edema pretibial discreto; la tomografía axial computada de cerebro no mostró edema, lesión ocupante de espacio o hemorragia. Los resultados de laboratorio mostraron bioquímica sanguínea normal y antiestreptolisina O elevada. Se manejó el caso como una GNAPE con evolución favorable. Conclusión. El diagnóstico de GNAPE se debe sospechar en niños con historia de infección de vías respiratorias superiores que se presentan con encefalopatía hipertensiva súbita.

Introduction. Acute post-streptococcal glomerulonephritis (APS-GN) is the leading cause of nephritic syndrome in children and has a broad spectrum of clinical presentation ranging from asymptomatic cases to acute renal failure and encephalopathy. Most cases are sporadic although the disease may occur in epidemic form, mainly related to poor sanitary conditions. Hypertensive encephalopathy is a severe complication, but there is a good outcome with appropriate treatment. Case report. We describe the case of a previously healthy 10-year-old male with a history of pharyngitis 1 week before his arrival to the emergency room. He presented with altered consciousness, partial seizures, hypertension and hematuria. Cranial computed tomography was performed and showed no edema, mass or hemorrhage; antistreptolysin O serum titers were elevated. He was treated according to hypertensive encephalopathy due to APSGN, with a favorable outcome. Differential diagnosis should include cerebral vascular diseases, intracranial tumors, central nervous system infections and toxic metabolic disturb ances. Conclusion. APSGN should be suspected in any child with history of pharyngitis and sudden onset of hypertensive encephalopathy.