RESUMO
BACKGROUND: Giardia lamblia is a flagellated protozoan causing diarrheal outbreaks worldwide. Microscopic stool examination is widely used. We conducted this study to explore intestinal giardiasis in children undergoing upper endoscopy for unexplained gastrointestinal symptoms. METHODS: The study included 160 children undergoing upper endoscopy for unexplained gastrointestinal symptoms (patients) and 90 children as controls. We collected stool samples for microscopic examination and ELISA coproantigen detection from all participants. We examined duodenal biopsies for patients. RESULTS: In patients, stool examination revealed Giardia in 23.8% and coproantigen detection was positive in 37.5%. Endoscopic duodenal biopsies revealed Giardia trophozoites in 5% of patients, in addition to various pathological changes. CONCLUSION: Giardiasis was significantly higher (P = 0.001) in children with unexplained gastrointestinal complaints than the controls. Diagnosis by coproantigen detection was superior to microscopic stool examination, with a sensitivity of 90.9%. Duodenal biopsies examination confirmed the infection in fewer cases but added other diagnostic information.