What are the indications for a water soluble contrast enema?
Water-soluble contrast agents use iodine as the x-ray absorber rather than barium. A water-soluble enema is used if there is concern for a colonic perforation because water-soluble contrast material is safer in the peritoneal space than barium. Water-soluble contrast agents are rapidly resorbed from the peritoneal cavity, and the iodine is excreted by the kidneys. In comparison, if barium and feces spill into the peritoneal cavity, a severe, potentially life-threatening granulomatous peritonitis may ensue.
Some surgeons prefer that water-soluble contrast agents are used in patients with suspected colonic obstruction because the presence of residual barium in the colon would make spillage of colonic contrast agent at surgery more problematic. Water-soluble contrast agents may also be used in patients who may have a difficult time expelling barium from the colon before it forms concretions. These patients include debilitated, bedridden patients; patients on narcotic medications or medications with anticholinergic side effects; or patients in whom an oral preparation is contraindicated, such as patients with small bowel obstruction.