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Chapter 325 Ileus, Adhesions, Intussusception, and Closed-Loop Obstructions
325.1 Ileus
Andrew Chu, Chris A. Liacouras
Ileus is the failure of intestinal peristalsis caused by loss of coordinated gut motility without evidence of mechanical obstruction. In children, it is most often associated with abdominal surgery or infection (pneumonia, gastroenteritis, peritonitis). Ileus also accompanies metabolic abnormalities (e.g. uremia, hypokalemia, hypercalcemia, hypermagnesemia, acidosis) or administration of certain drugs, such as opiates, vincristine, and antimotility agents such as loperamide when used during gastroenteritis.
Ileus manifests as increasing abdominal distention, emesis, and pain that worsens with distention. Bowel sounds are minimal or absent, in contrast to early mechanical obstruction, when they are hyperactive. Plain abdominal radiographs demonstrate multiple air-fluid levels throughout the abdomen. Serial radiographs usually do not show progressive distention as they do in mechanical obstruction. Contrast radiographs, if performed, demonstrate slow movement of barium through a patent lumen.
Treatment of ileus involves correcting the underlying abnormality. Nasogastric decompression is used to relieve recurrent vomiting or abdominal distention associated with pain. Ileus after abdominal surgery generally resolves in 24-72 hr. Prokinetic agents such as metoclopramide or erythromycin have been thought to hasten the return of normal bowel motility, but clinical data are inconclusive. The development of selective peripheral opioid antagonists such as methylnaltrexone holds promise in decreasing postoperative ileus, but pediatric data are lacking.
Bibliography
Mattei P, Rombeau JL. Review of the pathophysiology and management of postoperative ileus. World J Surg. 2006;30:1382-1391.
Thomas J, Karver S, Cooney GA, et al. Methylnaltrexone for opioid-induced constipation in advanced illness. N Engl J Med. 2008;358:2332-2343.
325.2 Adhesions
Adhesions are fibrous tissue bands that result from peritoneal injury. They can constrict hollow organs and are a major cause of postoperative small bowel obstruction. Most remain asymptomatic, but problems can arise anytime after the 2nd postoperative wk to years after surgery, regardless of surgical extent. In 1 study, the 5-year readmission risk due to adhesions varied by operative region (2.1% for colon to 9.2% for ileum) and procedure (0.3% for appendectomy to 25% for ileostomy formation/closure). The overall risk was 5.3% excluding appendectomy and 1.1% when they were included.
The diagnosis is suspected in patients with abdominal pain, constipation, emesis, and a history of intraperitoneal surgery. Nausea and vomiting quickly follow onset of pain. Initially, bowel sounds are hyperactive, and the abdomen is flat. Subsequently, bowel sounds disappear, and bowel dilation can cause abdominal distention. Fever and leukocytosis suggest bowel necrosis and peritonitis. Plain radiographs demonstrate obstructive features, and a CT scan or contrast studies may be needed to define the etiology.
Management includes nasogastric decompression, intravenous fluid resuscitation, and broad-spectrum antibiotics in preparation for surgery. Nonoperative intervention is contraindicated unless a patient is stable with obvious clinical improvement. In children with repeated obstruction, fibrin-glued plication of adjacent small bowel loops can reduce the risk of recurrent problems. Long-term complications include female infertility, failure to thrive, and chronic abdominal and/or pelvic pain.
Grant HW, Parker MC, Wilson MS, et al. Adhesions after abdominal surgery in children. J Pediatr Surg. 2008;43:152-156.
325.3 Intussusception
Melissa Kennedy, Chris A. Liacouras
Intussusception occurs when a portion of the alimentary tract is telescoped into an adjacent segment. It is the most common cause of intestinal obstruction between 3 mo and 6 yr of age and the most common abdominal emergency in children <2 yr. Sixty percent of patients are <1 yr of age, and 80% of the cases occur before age 24 mo; it is rare in neonates. The incidence varies from 1 to 4/1,000 live births. The male : female ratio is 3 : 1. A few intussusceptions reduce spontaneously, but if left untreated, most lead to intestinal infarction, perforation, peritonitis, and death.
Approximately 90% of cases of intussusception in children are idiopathic. The seasonal incidence has peaks in spring and autumn. Correlation with prior or concurrent respiratory adenovirus (type C) infection has been noted, and the condition can complicate otitis media, gastroenteritis, Henoch-Schönlein purpura, or upper respiratory tract infections. The risk of intussusception was increased in infants ≤1 yr of age after receiving a tetravalent rhesus-human reassortant rotavirus vaccine within 2 wk of immunization. The Advisory Committee on Immunization Practices no longer recommends this vaccine, and it is no longer available. Although rotavirus produces an enterotoxin, there is no association between wild-type human rotavirus and intussusception. The currently approved rotavirus vaccines have not been associated with an increased risk of intussusception.
It is postulated that gastrointestinal infection or the introduction of new food proteins results in swollen Peyer patches in the terminal ileum. Lymphoid nodular hyperplasia is another related risk factor. Prominent mounds of lymph tissue lead to mucosal prolapse of the ileum into the colon, thus causing an intussusception. In 2-8% of patients, recognizable lead points
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