The vomiting may be feculent if the obstruction has been long-standing. Colicky pain occurs at intervals of 10 minutes or more, and it is less intense. A dull ache may persist between cramps. Colic is perceived in the lower abdomen or suprapubically, and obstipation and distention are characteristic. Nausea is common, and vomiting may occur.
Tenderness is usually mild in uncomplicated colonic obstruction.
Rectal exam or sigmoidoscopy may detect an the obstructing lesion. Strangulated obstruction is characterized by constant pain, fever, tachycardia, peritoneal signs, a tender abdominal mass, and leukocytosis. Hypokalemic alkalosis is the most common metabolic abnormality resulting from vomiting and fluid loss. Elevated BUN and creatinine suggests significant hypovolemia. Hypochloremic acidosis with increased anion gap may occur with strangulated obstruction.