Of all hospital admissions in the U.S. every year for abdominal pain, a full 15 percent result from bowel obstructions. That amounts to about 300,000 emergency admissions, and of these, 30,000 patients will die. These alarming statistics from the May 2008 issue of the journal Medical Clinics of North America underscore the obvious importance of understanding this disorder and recognizing its symptoms.
Anatomy
The symptoms of bowel obstruction in adults differ depending on where the blockage occurs. The stomach leads to the small intestine. It then winds through the abdomen and transitions to the large intestine. The large intestine eventually empties into the rectum for elimination of waste out of the body. Obstructions occurring low down in the intestines present with cramping abdominal pain, initial loose stool and then as the obstruction worsens, absence of gas or stool altogether. Obstructions higher up in the bowel show waves of abdominal pain accompanied by nausea and vomiting, progressing to decreased or absent stool output. Distension of the abdomen occurs late in the process of bowel blockage.
Causes
Scar tissue from previous surgeries can form "adhesions" that bind to and constrict part of the bowel, causing a blockage with the characteristic symptoms. These adhesions cause the great majority---more than 60 percent---of bowel obstructions, according to the "Sabiston Textbook of Surgery." Medical Clinics of North America puts this number higher at 75 percent, followed by hernias causing another 15 percent. Hernias are weaknesses in the wall of the abdomen below the skin. A loop of intestine slips through the weakness and gets stuck, causing the bowel to become blocked. Tumors make up a smaller percentage and result from both primary bowel tumors and metastatic tumors from elsewhere.
Diagnosis
Along with the characteristic symptoms, patients often give a history of prior surgery in the abdomen. Partial bowel obstructions, where some material can pass through, are also common with similar but less severe symptoms. On exam, the patient shows signs of obvious discomfort, and with complete obstruction can have fever, low blood pressure or a high heart rate. Since well over 50 percent of cases can be diagnosed with a plain X-ray of the abdomen, this generally represents the first diagnostic study. CT scan, ultrasound, MRI and other specialized tests can be used to obtain more information about the extent and cause of the obstruction.
Treatment
Treatment begins with placement of a naso-gastric tube. This thin, hollow, flexible plastic tube enters the nose, travels down the esophagus and ends in the stomach. By applying gentle suction, the stomach is emptied, relieving many symptoms such as nausea, distension and vomiting. Bowel rest, meaning no food or drink is allowed, constitutes a mainstay of therapy. Fluids, given intravenously, relieve dehydration and support a low blood pressure. Partial obstructions usually resolve on their own, while surgical intervention can be required for a complete obstruction, usually within 24 hours to minimize the risk of death.
Warning
A bowel obstruction constitutes a serious medical condition that can become a life-threatening emergency. Symptoms of abdominal pain, nausea, vomiting and decreased stool output must be immediately evaluated and treated by a qualified physician, in an emergency room if necessary. No attempts to self-diagnose or treat should be made if these or any other concerning symptoms are present.
References
- "Medical Clinics of North America"; Mechanical Obstruction of the Small Bowel and Colon; Mitchell S. Cappell, MD, PhD andl Mihaela Batke, MD; May 2008
- "Sabiston Textbook of Surgery, 18th edition"; Courtney M. Townsend, MD, et al, editors; 2007
- Medline Plus: Intestinal Obstruction
