pathophysiology
Last reviewed 01/2018
In patients with long standing constipation there is a tendency to develop a capacious, elongated and relatively atonic colon, particularly in the region of the sigmoid colon. The redundant sigmoid colon is on a long mesentery with a narrow base.
The huge sigmoid, heavy with faeces and distended with gas, may occasionally become twisted on its mesenteric axis to produce a closed loop obstruction - sigmoid volvulus. If the condition is not resolved then venous infarction follows and, if not corrected, perforation and faecal peritonitis may ensue.
Note that other types of volvulus in the gastrointestinal tract are not related to constipation.