Uninhibited sigmoid colon syndrome (sigmoid hyperreflexia): description of a new clinicopathological entity

To present 10 patients who complained of passage of frequent loose stools which was found to be due to sigmoid colon hyperreflexia, a condition that, to our knowledge, has not been described before.

Ten patients (6 women, 4 men, mean age 46.6 years) complaining of frequent loose stools of 5-8 years' duration and 10 healthy volunteers (controls) matching the patients in age and gender, were included in the study. Colonoscopy, barium enema and intestinal transit studies were normal in all. The anorectal physiological studies comprised: recording of rectal, anal and intra-abdominal pressures, EMG of the external and internal anal sphincters and levator ani muscles, sigmoidometry and determination of the sigmoido-rectal junction reflex.

Apart from sigmoidometry, all the aforementioned anorectal physiological studies were in accordance with those of the controls. Sigmoidometry showed that balloon expulsion occurred at a distending volume of 32.4 ml and a sigmoid colon pressure of 86.4 cmH2O in the patients, and of 86.2 ml and 98.6 cmH2O, respectively, in the controls. The tone limb exhibited major fluctuations (mean pressure rise 43.8 cmH2O) in the patients, while it was smooth or showed minor fluctuations (insignificant pressure changes) in the controls.

The sigmoid colon contractions produced by small volumes of stools and the lack of proper storage necessary for water absorption from the stools, are suggested to explain the frequent loose stools in the studied patients and to be the result of sigmoid colon hyperreflexia.