Proctalgia fugax: This is a disorder of the rectum that results in episodes of severe rectal pain that come on suddenly and go away on their own after a few minutes or less. A spasm, or tightening, of muscles in the pelvis and anal canal causes proctalgia fugax. It does not typically cause long-term problems or complications. Factors that trigger the pain can include stress, bowel movements, sexual activity, constipation, or menstrual periods in women.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.