"Current Diagnosis & Treatment: Surgery" states that small bowel obstructions are the most common surgical problem of the small intestine. These obstructions present with colicky abdominal pain, profuse vomiting and nausea. Resolution of a partial small bowel obstruction may be accomplished by pushing air through the intestine, but a complete small bowel obstruction almost always requires surgery. The causes of small bowel obstructions are varied.
Intraluminal
Intraluminal causes of small bowel obstructions are those which occur within the lumen, or cavity, of the small bowel. A foreign body may obstruct the passage of stool in the small bowel, such as a large indigestible object. Gallstones from the gallbladder may pass through the common bile duct and into the intestine, causing obstruction in an area of narrowing. Meconium refers to the thick mucousy fecal matter found inside the intestine of a newborn child. Because of its viscosity and the immature nature of an infant's intestines, this can also cause small bowel obstruction, states ""Current Diagnosis & Treatment: Surgery."
Intramural
Disorders of the wall of the small intestine can cause obstruction by causing the wall to grow large enough to block the flow of feces. A cancerous growth is one example of such a disorder. "Schwartz's Principles of Surgery" states that most commonly, a cancer-related small bowel obstruction is due to invasion by advanced malignancies arising in organs other than the small bowel. Crohn's disease and ulcerative colitis, two inflammatory disorders of the intestines, can also cause enough inflammation and resultant fibrosis and scar tissue formation to interfere with intestinal functioning.
Extrinsic
Extrinsic causes of bowel obstruction are by far the most common. According to "Schwartz's Principles of Surgery," intra-abdominal adhesions related to prior abdominal surgery account for up to 75% of the cases of small bowel obstruction. An adhesion occurs when inflamed tissue healing after an abdominal surgery connects and heals together. The resultant scar tissue can contract, constricting the bowel. A rare cause of extrinsic bowel obstruction is the superior mesenteric artery syndrome. This occurs when the superior mesenteric artery compresses the third portion of the duodenum--an early portion of the small bowel--as it crosses over. This is commonly a congenital condition.
References
- "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
- "Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 6e"; Judith E. Tintinalli, MD, MS, Gabor D. Kelen, MD, J. Stephan Stapczynski, MD, O. John Ma, MD and David M. Cline, MD; 2004
- "Current Diagnosis & Treatment: Surgery, 13e"; Gerard M. Doherty, ed.; 2010
