Bowel Obstruction

accurate but involves radiation exposure. The ultrasound will sometimes be complicated by intestinal gases.

The mortality rate is more than 50 percent if there is no treatment. If treated surgically, the mortality rate is less than one percent. The treatment is largely surgical but IV fluids and antibiotics play a role. Patients who have inflammatory bowel disease of the cecum should not have surgical excision. Third generation cephalosporins are most commonly used prior to surgery.

BOWEL OBSTRUCTION

A bowel obstruction or intestinal obstruction is a mechanical blockage of the intestines with limited passage of intra-intestinal contents through the intestinal lumen. Patients will have a lack of flatus, obstipation, crampy pain, and vomiting. It can involve the large or small intestine. Most partial obstructions do not require surgery, while 85 percent of complete obstructions require surgery.

The most common causes of obstruction include adhesions, tumors, and hernias. In the postoperative patient, adhesions are the most common cause of this problem. Other less common causes include intussusception, diverticulitis, volvulus, foreign bodies, and fecal impaction.

If the obstruction is purely mechanical, it is rare to have vascular compromise. Fluid, secretions, and food will accumulate above the level of obstruction with distention of proximal bowel. There will be congestion and edema of the bowel, which progresses the problem. If the blood flow strangulates the bowel, this can lead to perforation secondary to gangrene. Perforation can be segmental in an ischemic segment; perforation can also be secondary to marked dilation of the intestine above the obstruction.

Small bowel obstruction happens quickly, with periumbilical or epigastric pain, obstipation, and vomiting. Partial obstruction often leads to diarrhea. Steady pain suggests strangulation. Listen for hyperactive and high-pitched bowel sounds. Dilated loops of bowel may be palpable. If there is infarction, the bowel will be silent; late findings are oliguria and shock.

Large bowel obstruction happens more slowly over time and involves fewer symptoms than is seen in small bowel obstruction. A major finding is increased constipation that leads to obstipation. Vomiting is less common. Patients will have lower abdominal cramps, abdominal distention and loud bowel sounds. The rectum will be empty. Sometime a mass can be detected on palpation. One difference between most causes of obstruction and volvulus is that the volvulus involves a more abrupt onset.

As mentioned, a flat and upright of the abdomen or a flat and lateral recumbent film will be helpful in a bowel obstruction. Serial x-rays can sometimes detect strangulation early. If there is acidosis and leukocytosis, this can also suggest strangulation. A CT scan of the abdomen will also show obstructive pathology in the abdomen. Gas in the bowel wall suggests necrosis and gangrene.

In treating the patient, provide IV fluids and nasogastric suction with IV antibiotics if bowel ischemia is suspected. Involve a surgeon early in the process. The antibiotic of choice is a third-generation cephalosporin, such as cefotetan.

With duodenal obstruction, resection may be necessary; if it is not possible, a palliative gastrojejunostomy is performed. Gallstones are removed if these are causative but a cholecystectomy is not done if the patient is very sick. Hernias should be repaired and adhesions lysed if these are behind the obstruction. Recurrent adhesional obstruction are treated with NG tube insertion rather than surgery. Patients with obstruction secondary to cancer may be able to have tumor resection unless the cancer is disseminated.

Specialized cases of obstruction include diverticulitis, which is often complicated by perforation. It may be difficult to remove the diverticula so a colostomy may be necessary with reanastomosis done at a later date. Fecal impaction can be cleaned out manually. A cecal volvulus can be resected with immediate anastomosis.