A 25-year-old man comes to the emergency department due to abdominal pain, nausea, and vomiting. The symptoms began 2 months ago, at which time the pain was intermittent and located in the right lower quadrant. Since then, it has progressed and is now diffuse, severe, and unremitting. The patient started vomiting bilious fluid 2 days ago but has not had hematemesis, melena, hematochezia, diarrhea, or unexpected weight loss. In addition, he has not moved his bowels in 2 days, although he frequently passes flatus. Medical history is significant for Crohn disease with ileal involvement, which is currently managed with infliximab and has never required surgery. The patient has used acetaminophen and ibuprofen to relieve his pain and has not used narcotics. He smokes 3-4 cigarettes a day but does not use alcohol or illicit drugs. Temperature is 37.5 C (99.5 F), blood pressure is 134/78, pulse is 95/min, and respirations are 18/min. On physical examination, the patient is awake and cooperative. Chest examination is unremarkable. The abdomen is distended, tympanic, and tender to palpation; there is no rebound tenderness or guarding. Which of the following most likely explains this patient's presentation?

Question

A 25-year-old man comes to the emergency department due to abdominal pain, nausea, and vomiting.  The symptoms began 2 months ago, at which time the pain was intermittent and located in the right lower quadrant.  Since then, it has progressed and is now diffuse, severe, and unremitting.  The patient started vomiting bilious fluid 2 days ago but has not had hematemesis, melena, hematochezia, diarrhea, or unexpected weight loss.  In addition, he has not moved his bowels in 2 days, although he frequently passes flatus.  Medical history is significant for Crohn disease with ileal involvement, which is currently managed with infliximab and has never required surgery.  The patient has used acetaminophen and ibuprofen to relieve his pain and has not used narcotics.  He smokes 3-4 cigarettes a day but does not use alcohol or illicit drugs.  Temperature is 37.5 C (99.5 F), blood pressure is 134/78, pulse is 95/min, and respirations are 18/min.  On physical examination, the patient is awake and cooperative.  Chest examination is unremarkable.  The abdomen is distended, tympanic, and tender to palpation; there is no rebound tenderness or guarding.  Which of the following most likely explains this patient's presentation?

Quizplus · Accepted Answer

This patient with Crohn disease most likely has small bowel obstruction (SBO) due to a fibrotic stricture. Strictures are a complication of Crohn disease that result from poorly controlled, severe inflammation. Smoking and young age (<30) at diagnosis are significant risk factors for uncontrolled inflammation and disease progression despite medical therapy. complication SBO due to fibrotic stricture typically presents with bilious vomiting, severe abdominal pain, and either partial (ie, ability to pass gas but not stool) or complete (ie, inability to pass flatus or stool) obstruction. Abdominal examination commonly reveals distension and high-pitched (tympanic) bowel sounds. Although medical treatment for Crohn disease (eg, infliximab) can reduce inflammation and may help prevent fibrotic stricture development it cannot resolve a stricture once one develops. Depending on the location and length of the stricture, surgical resection may be required. (Choice A) Infliximab and other tumor necrosis factor-alpha antagonists (eg, adalimumab) are commonly used to treat Crohn disease. They are usually well tolerated but can increase a patient's risk for infection and malignancy. Gastrointestinal distress is not a typical adverse effect. (Choice B) Adynamic ileus occurs when small bowel motility is disrupted, leading to intestinal dilation, obstipation, and bilious emesis. Although it presents similarly to SBO, adynamic ileus only develops after exposure to an insult that "stuns" the bowel, such as recent intra-abdominal surgery or high-dose opioids. (Choices C and F) Toxic megacolon can complicate both ulcerative colitis and severe Clostridioides (formerly Clostridium) difficile colitis; it presents with colonic dilation, obstipation, vomiting, and hemodynamic instability. This patient's Crohn disease only involves the small bowel, and since he never had watery diarrhea (a hallmark sign of C difficile), toxic megacolon is exceedingly unlikely. (Choice E) Crohn disease is a risk factor for small bowel cancer, which can lead to SBO; however, one would expect severe weight loss if small bowel cancer were present. Educational objective: Severe, uncontrolled inflammation in Crohn disease can lead to a fibrotic stricture of the small bowel with small bowel obstruction (SBO); smoking and young age (<30) at diagnosis increase the risk of such disease progression. Fibrotic stricture with SBO presents with bilious emesis, severe abdominal pain, and inability to pass flatus and/or stool. Treatment usually requires surgical removal of the strictured portion of small bowel.

A 25-Year-Old Man Comes to the Emergency Department Due to Abdominal