What are the features of colonic obstruction ?

Answer is 'a' i.e. No passage of gas absolutely (obstipation); 'b' i.e. No passage of stools absolutely; 'c' i.e. Distention of abdomen Colonic obstruction may occur in any poion of the colon, but most commonly is seen in the sigmoid colon. Obstruction at the ileocecal valve produces symptoms and signs of small bowel obstruction. So do obstruction in proximal asc. colon if the ileo-cecal valve becomes incompetent. The pathophysiology of more distal colonic obstruction depends on the competence of the ileocecal valve. If the ileocecal valve is incompetent the colonic pressure is relieved by reflux into the ileum. If the colon is not decompressed through the ileocecal valve, a 'closed loop' is formed between the valve and the obstructing point. The colon distends progressively because the ileum continues to empty gas and liquids into the obstructed segment. Increasing colonic pressure may lead to impaired circulation with gangren and perforation. The risk of perforation is highest in the cecum. Symptoms & signs - depend on the degree and acuity of obstruction, as well as on the cause. Abdominal distention is the most prominent initial finding. Pain is cramping in nature but of less severity than seen in small bowel obstruction. Vomiting is late and occurs only if the ileocecal valve is incompetent. Feculant vomiting is very rare (cf. feculant vomiting is seen in distal small bowel obstruction). Constipation or obstipation is a universal feature of complete obstruction, though the colon distal to the obstruction may empty after the initial symptom begins. So its a late feature even in complete obstruction. If ileocecal valve incompetence decompresses the colonic contents into the small intestine, features of both small & large intestine obstruction appears. Fever is commonly seen in acute diveiculitis, ischemic injury or perforation. (But I don't think its an early finding) Plain x-ray films will show peripheral gas filled dilated colon segments. Air fluids level will not be noted unless the ileocecal valve incompetence has decompressed the colonic contents into small intestine. Also know MC cause of colonic obstruction Ca colon