Prevalence of Giardiasis: a study at upper-gastrointestinal endoscopy.

The prevalence of giardiasis was assessed in 1000 consecutive adult patients undergoing upper-gastrointestinal endoscopy for the usually accepted indications. Patients with upper-gastrointestinal bleeding were excluded. The diagnosis was established by examination of duodenal aspirate and duodenal mucosal impression smears. In 21 patients (2.1%) trophozoites were detected both in the duodenal juice and stained mucosal impression smears. All were treated with metronidazole or tinidazole. In 14 of 16 patients who had subsequent duodenal intubation, eradication of the parasite was confirmed. In five patients previously existent abdominal pain disappeared with clearing of the parasite, and no other cause for their abdominal pain was discovered. A search for Giardia lamblia infestation may be a worthwhile additional procedure at the time of endoscopy when no other cause for abdominal pain is found.