A 66-year-old man comes to the emergency department due to worsening abdominal pain. Over the past week, he has had vague lower abdominal discomfort, nausea, anorexia, and constipation. This morning, the patient had sudden, severe lower abdominal pain accompanied by lightheadedness and an episode of vomiting. The pain initially improved but then gradually intensified to involve the entire abdomen. Medical history is significant for coronary artery disease and remote appendectomy. Temperature is 38.3 C (100.9 F), blood pressure is 110/54 mm Hg, pulse is 108/min, and respirations are 20/min. On physical examination, the patient is alert and cooperative but appears uncomfortable. Heart and lung sounds are normal. Bowel sounds are diminished. The abdomen is diffusely tender with guarding and rebound tenderness. Abdominal imaging is most likely to reveal which of the following findings in this patient?

Question

A 66-year-old man comes to the emergency department due to worsening abdominal pain.  Over the past week, he has had vague lower abdominal discomfort, nausea, anorexia, and constipation.  This morning, the patient had sudden, severe lower abdominal pain accompanied by lightheadedness and an episode of vomiting.  The pain initially improved but then gradually intensified to involve the entire abdomen.  Medical history is significant for coronary artery disease and remote appendectomy.  Temperature is 38.3 C (100.9 F), blood pressure is 110/54 mm Hg, pulse is 108/min, and respirations are 20/min.  On physical examination, the patient is alert and cooperative but appears uncomfortable.  Heart and lung sounds are normal.  Bowel sounds are diminished.  The abdomen is diffusely tender with guarding and rebound tenderness.  Abdominal imaging is most likely to reveal which of the following findings in this patient?

Quizplus · Accepted Answer

Explanation: This elderly patient with weeklong symptoms of likely diverticulitis (eg, vague lower abdominal discomfort, anorexia, constipation) experienced sudden, severe abdominal pain that temporarily improved and then spread to his entire abdomen. This presentation, now accompanied by fever and peritonitis (eg, guarding, rebound tenderness), is most consistent with diverticular perforation. Because free (ie, noncontained) perforation causes colonic contents to spill into the peritoneal cavity, free air is typically visible on abdominal imaging (eg, upright x-ray, CT scan). Patients with free perforation of the gastrointestinal tract in the setting of ongoing inflammation (eg, diverticulitis) often have a classic pain sequence: Moment of perforation: sudden, severe pain (± vomiting, lightheadedness or syncope) After perforation to 2 hours: temporary relief or decreased pain as the inflamed organ decompresses >2 hours after perforation: generalized, constant pain due to peritonitis (± sepsis/septic shock) Unlike diverticular microperforation (ie, contained perforation), which usually responds to medical management (eg, antibiotics, bowel rest), free perforation is a surgical emergency that requires abdominal washout and resection of the ruptured bowel segment. (Choice A) Colonic dilatation with loss of haustral markings may be seen in toxic megacolon. Toxic megacolon can cause fever, abdominal pain, and peritonitis. However, bloody diarrhea is typically present, as is a history of inflammatory bowel disease or recent antibiotic therapy (leading to Clostridioides [formerly Clostridium] difficile). (Choice B) Dilated small bowel with a transition point is seen in small bowel obstruction. This condition more commonly causes crampy (vs sudden and severe) pain of the midabdomen and increased, high-pitched (vs diminished) bowel sounds without peritonitis, unless perforation has occurred (causing free air on imaging). (Choice C) Embolic occlusion of a mesenteric artery causes acute-onset, severe abdominal pain (acute mesenteric ischemia). Such pain is typically out of proportion to a relatively benign abdominal examination, whereas this patient has guarding and rebound tenderness proportionate to his severe pain. In addition, a predisposing risk factor for embolism (eg, atrial fibrillation) is usually present. (Choice E) A hematoma surrounding the abdominal aorta may been seen with contained abdominal aortic aneurysm rupture. Such rupture may cause acute-onset, severe abdominal pain; however, contained rupture does not typically cause fever and peritonitis. Educational objective: Free perforation of the gastrointestinal tract in the setting of ongoing inflammation (eg, diverticulitis) often causes a classic pain sequence: sudden, severe pain (perforation) followed by temporary relief (decompression) and then generalized, constant pain (peritonitis). Abdominal imaging typically shows intraperitoneal free air. References: Colorectal emergencies: perforated diverticulitis (operative and nonoperative management). (http://www.ncbi.nlm.nih.gov/pubmed/24072684) Diverticulitis: a comprehensive review with usual and unusual complications. (http://www.ncbi.nlm.nih.gov/pubmed/27878550)

A 66-Year-Old Man Comes to the Emergency Department Due to Worsening