Association Between Giardia Duodenalis Infection and Irritable Bowel Syndrome

Some studies have shown that giardia infection is associated with some abdominal symptoms. The aim of this study was to determine the relationship between giardia duodenalis infection and irritable bowel syndrome (IBS). In this clinical trial study, 60 patients with non-constipation predominant IBS based on Rome III criteria were enrolled in the study. 30 patients with giardiasis who were diagnosed with stool Eliza as patients, and 30 other patients who did not have giardiasis as control enrolled to study. All patients were treated with 250 milligrams of metronidazole TDS for 5 days. Abdominal symptoms including abdominal pain, bloating, and diarrhea were determined and compared in both groups before and after treatment. The mean age and sex distribution of the two groups were similar (P>0.5). The pain, bloating, and diarrhea severity before treatment with metronidazole were not significantly different in the two groups. The pain and bloating and diarrhea severity in both groups significantly decreased after the treatment period, but reductions were significantly higher in the case group (P<0.001 and P<0.001 P<0.001, respectively). The mean score of global symptoms before treatment in both case and control groups was similar. (P=0.88), but after treatment it was 4.85±2.18 (P<0.001) and 10.48±2.14 (P<0.001) respectively and the difference between the two groups was significant (P<0.001). The recovery percentage was 0.61±0.16 in the case group and 0.14±0.17 in the control group (P<0.001). Giardia infection in patients with IBS seems to play a significant role in clinical manifestations of non-constipation IBS and treatment with metronidazole can improve these symptoms significantly.