A case of giardiasis diagnosed by analysis of lavage fluid collected during colonoscopy

Abstract

Giardia lamblia is one cause of prolonged diarrhea in overseas travelers. Demonstration of trophozoites in stool is the traditional method of diagnosis. Here we present a case of giardiasis diagnosed by lavage fluid collected during colonoscopy (CS) .A 60-year-old woman presented at our hospital with prolonged watery diarrhea since travel in Southeast Asia. She had been treated empirically due to negative results from EGD, CS and stool culture. A second CS was performed one year and nine months after the first CS, because the diarrhea persisted. Trophozoites of Giardia lamblia were detected microscopically in lavage fluid sediment collected during this CS. Oral administration of metronidazole (750 mg/day) for one week dramatically improved the patient’s symptoms. This case suggests that CS lavage fluid assessment is a useful method to detect Giardia lamblia in patients with chronic diarrhea.