Background : Post-infectious irritable bowel syndrome is associated with increased serotonin-containing enterochromaffin cells and lymphocytes in rectal biopsies. Animal studies have suggested that steroids reduce the lymphocyte response and suppress some of the post-infectious changes in neuromuscular function.
Aim : To evaluate whether steroids reduce the number of enterochromaffin cells and improve the symptoms of post-infectious irritable bowel syndrome.
Methods : Twenty-nine patients with post-infectious irritable bowel syndrome underwent a randomized, double-blind, placebo-controlled trial of 3 weeks of oral prednisolone, 30 mg/day. Mucosal enterochromaffin cells, T lymphocytes and mast cells were assessed in rectal biopsies before and after treatment, and bowel symptoms were recorded in a daily diary.
Results: Initial enterochromaffin cell counts were increased and correlated with initial lamina propria T-lymphocyte counts (r = 0.460, P = 0.014). Enterochromaffin cell counts did not change significantly after either prednisolone (− 0.8% ± 9.2%) or placebo (7.9% ± 7.9%) (P = 0.5). Although lamina propria T-lymphocyte counts decreased significantly after prednisolone (22.0% ± 5.6%, P = 0.003), but not after placebo (11.5% ± 8.6%, P = 0.1), this was not associated with any significant treatment-related improvement in abdominal pain, diarrhoea, frequency or urgency.
Conclusions : Prednisolone does not appear to reduce the number of enterochromaffin cells or cause an improvement in symptoms in post-infectious irritable bowel syndrome. Other approaches to this persistent condition are indicated.