According to "Schwartz's Principles of Surgery," obstruction is the most common surgical disorder of the small intestine. It can result from a variety of pathologic conditions, including those which originate within the bowel itself and those which affect the bowel from the exterior. The most common cause is an intra-abdominal adhesion related to prior abdominal surgery, which accounts for approximately 75 percent of the cases of small bowel obstruction. The signs and symptoms of a partial small bowel obstruction are largely identical to the signs and symptoms of a complete small bowel obstruction.
Symptoms
The symptoms of small bowel obstruction can unfortunately be fairly nonspecific. They may include cramping abdominal pain located around the umbilicus, which has a typical pattern of persisting for a few minutes and then going away, only to return a few minutes later. However, depending upon the location of the small bowel obstruction, the pain may be located in the upper part of the abdomen or diffusely throughout the abdomen instead of near the umbilicus. Nausea and vomiting is another common sign of small bowel obstruction. The vomiting is typically profuse, and in cases of a distal small bowel obstruction may become foul smelling and feculent. This means that portions of the vomit are made up of partially digested material from the intestine which were unable to pass the obstruction.
Signs
The physical examination signs exhibited by a patient with small bowel obstruction--partial or complete--include abdominal distention, tenderness and hyperactive bowel sounds. The amount of abdominal distention varies depending upon the location of the obstruction. A more distal obstruction will result in a greater amount of abdominal distention. A patient with a partial small bowel obstruction will typically have a mild and diffuse level of tenderness to palpation. However, if a portion of bowel is strangulated--or trapped tightly enough that its blood supply is cut off--then the amount of tenderness can be severe. The bowel sounds heard through a stethoscope will initially be very hyperactive as the intestine attempts to push past the obstructed section. In late obstruction, the bowel sounds may become hypoactive or absent entirely.
Imaging
The initial imaging test performed in the hospital for suspected small bowel obstruction is often an abdominal X-ray. This can be performed while the patient is lying flat or sitting or standing upright. This X-ray would generally demonstrate dilated small bowel with air-fluid levels. Air-fluid levels are features on an X-ray which represent the border between an area of liquid and an area gas. In the case of a small bowel obstruction, these levels are present because of the buildup of fecal material and air proximal to the obstruction. "Tintinalli's Emergency Medicine" states that if the diagnosis is in doubt, a CT scan with the administration of oral contrast is highly accurate as confirmation.
References
- "Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 6e"; Drs. Judith E. Tintinalli, Gabor D. Kelen, MD, J. Stephan Stapczynski, MD, O. John Ma and David M. Cline; 2004
- "Schwartz's Principles of Surgery, 9e"; F. Charles Brunicardi, Dana K. Andersen, Timothy R. Billiar, David L. Dunn, John G. Hunter, Jeffrey B. Matthews, Raphael E. Pollock; 2010
