Anal Sphincter Myopathy, Internal

Kamm et al. (1991) described a family in which at least 1 member in each of 5 successive generations had severe proctalgia fugax beginning in the third to fifth decades of life. They studied in detail 3 members of the family demonstrating a 'new' myopathy of the internal anal sphincter. Each affected member had severe pain intermittently during the day and hourly during the night. Clinically the internal anal sphincter was thickened and of decreased compliance. The maximum anal canal pressure was usually increased with marked ultraslow wave activity. One patient showed marked improvement with strip myectomy of the internal anal sphincter; a second was relieved of constipation but had only slight improvement of pain. The hypertrophied muscle showed unique myopathic changes, consisting of vacuolar changes with periodic acid-Schiff-positive polyglycosan bodies in the smooth muscle fibers and increased endomysial fibrosis. Celik et al. (1995) described anorectal ultrasonography, manometry and sensory testing in 3 affected persons from a family with autosomal dominant inheritance of proctalgia fugax. Two affected members had hypertension as well as proctalgia fugax; treatment with the calcium antagonist nifedipine reduced anal tone, decreased the frequency and intensity of anal pain, and returned blood pressure to the normal range.

('Proctalgia fugax' means fleeting pain in the rectum. The same Latin root, fugere (to flee), appears in 'fugitive' and 'centrifugal.')