PURPOSE:The pathophysiology of sporadic proctalgia fugax remains unknown. This study investigates whether patients with this syndrome exhibit alterations in anal function and morphology.METHODS:Eighteen patients with sporadic proctalgia fugax and 18 sex‐matched and age‐matched healthy controls were studied. Manometric studies investigated anal resting and squeeze pressures, the rectoanal inhibitory reflex, rectal compliance, and smooth muscle response to edrophonium chloride administration. External and internal sphincter thickness was measured endosonographically.RESULTS:Patients had slightly higher(P=0.0291) anal resting pressures (65.5±11.4 mmHg) than controls (56±9.9 mmHg). However, anal squeeze pressure, sphincter relaxation during rectal distention, and rectal compliance were similar in both groups, and no alterations were detected in external and internal anal sphincter thickness. Edrophonium chloride administration was followed by sharp postrelaxation contractions in two patients, whereas anal function remained unaltered in controls. Acute episodes of proctalgia, which occurred in two patients while under study, were associated with a rise in anal resting tone and an increase in slow wave amplitude.CONCLUSIONS:In the resting state, patients with proctalgia fugax have normal anorectal function and morphology. However, they may exhibit a motor abnormality of the anal smooth muscle during an acute attack.