[Fever of unknown origin: a challenge for the pediatric infectious diseases specialist]. / Síndrome febril prolongado: un desafío para el infectólogo pediatra.

INTRODUCTION: Prolonged febrile syndrome (PFS) is defined as fever 7-10 days, with initial study does not allow etiologic diagnosis. OBJECTIVE: To describe the main causes of the PFS and its temporal behavior in Pediatric Infectious Diseases Unit Outpatient Care of Complejo Asistencial Dr. Sótero del Río (CASR). PATIENTS AND METHODS: A descriptive, prospective study between january 2007-december 2012, about 153 patients from 6 weeks to 14 years 11 months old, diagnosed with PFS, tab completing clinical and laboratory monitoring. RESULTS: etiology was obtained in 67.9%, the causes were infection (88.4%), neoplasms (4.8%), rheumatological (4.8%) and Kawasaki disease (2.8%). The most important infectious causes were enteric fevers (typhoid and paratyphoid) (18.4%), urinary tract infection (11.9%), Bartonella henselae infections and adenovirus (8.7%) each one and Epstein Barr virus (7.6%). Ninety eight percent of patients had complete resolution, 60.7% did not require hospitalization and mortality was 0%. DISCUSSION: As in previous pediatric clinical series the infections were the most frequent causes. Enteric fever persists as principal cause, however, the epidemiological evidence is oscillating in time endorsing the local statistics can count over the years to improve the diagnostic and therapeutic approach.