Therapy of a small bowel obstruction usually consists of prompt surgical correction. In patients with no evidence of closed -loop obstruction, and in whom there is no fever or leukocytosis or tachycardia, a period of careful observation with nasogastric decompression may be successful in all of the following conditions EXCEPT:
Partial small bowel obstruction and early postoperative obstruction can mimic ileus, and may respond to nonoperative therapy. Crohn disease usually responds to medical therapy, although recurrent obstruction is an indication for surgical correction. Obstruction due to an internal hernia requires prompt surgical intervention to avoid strangulation and necrosis.
Interventions which may reduce the incidence and duration of postoperative ileus include all of the following EXCEPT:
Epidural analgesia (with reduced systemic narcotic administration), avoiding excess intra- and postoperative fluid administration, and administration of alvimopan, a μ-opioid receptor antagonist, have all been associated with reduced incidence and/or duration of postoperative ileus. Prokinetic agents such as metoclopramide and erythromycin are rarely useful.
Risk factors for the development of Crohn's disease include all of the following EXCEPT:
The risk of having Crohn's disease is two- to fourfold higher in Ashkenazi Jewish families, 15 times higher in family members of a patient with Crohn's disease, and is increased in higher socioeconomic groups, and among smokers. The incidence in China is 1% of the incidence in the United States, although this number is increasing.
The primary genetic defect associated with Crohn's disease is a mutation of the NOD2 gene on chromosome 16. This gene encodes for a protein product which:
The protein product of the NOD2 gene mediates the innate immune response to microbial pathogens. A variety of defects in immune regulatory mechanisms such as overresponsiveness of mucosal T cells to enteric flora-derived antigens can lead to defective immune tolerance and sustained inflammation.
In the resection of a stenotic area of intestine in a patient with Crohn's disease, the best approach is:
There are no differences in the recurrence rates for resection with a 2-cm margin or a 12-cm margin from gross disease. The additional bowel lost may contribute to eventual short gut syndrome in a patient who requires multiple resections, so minimizing bowel loss is a priority. There is no benefit to achieving frozen section negative margins in the resection of Crohn's strictures; positive margin resections have the same recurrence rate as negative margin resections. The effort to obtain a frozen section negative margin carries the risk of removing more intestine than is necessary.
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