A 67-year-old man comes to the emergency department due to abdominal discomfort and distension. Five days ago, he began having large-volume watery stools 6-8 times daily after eating at a new restaurant. He also has had associated mild abdominal cramps and nausea but no fever, chills, vomiting, or bloody stools. His wife, who had the same food, also experienced similar symptoms. He self-treated with increased oral fluids and the stool frequency and consistency began to improve. However, his bowel movements abruptly stopped yesterday, and the diffuse abdominal discomfort and distension worsened. Medical history includes hypertension, coronary artery disease, and heart failure treated with diuretics. Temperature is 37 C (98.6 F), blood pressure is 116/72 mm Hg, and pulse is 102/min. Physical examination shows dry mucous membranes. The abdomen is distended, tympanic, and mildly tender to palpation with no guarding or rebound tenderness. Bowel sounds are decreased. Digital rectal examination reveals an empty rectal vault with no evidence of blood or melena. Abdominal CT scan shows diffuse colonic dilation with nondilated small bowels. Leukocyte count is normal and testing for Clostridioides (formerly Clostridium) difficile is negative. Which of the following most likely contributed to this patient's current condition?

Question

A 67-year-old man comes to the emergency department due to abdominal discomfort and distension.  Five days ago, he began having large-volume watery stools 6-8 times daily after eating at a new restaurant.  He also has had associated mild abdominal cramps and nausea but no fever, chills, vomiting, or bloody stools.  His wife, who had the same food, also experienced similar symptoms.  He self-treated with increased oral fluids and the stool frequency and consistency began to improve.  However, his bowel movements abruptly stopped yesterday, and the diffuse abdominal discomfort and distension worsened.  Medical history includes hypertension, coronary artery disease, and heart failure treated with diuretics.  Temperature is 37 C (98.6 F), blood pressure is 116/72 mm Hg, and pulse is 102/min.  Physical examination shows dry mucous membranes.  The abdomen is distended, tympanic, and mildly tender to palpation with no guarding or rebound tenderness.  Bowel sounds are decreased.  Digital rectal examination reveals an empty rectal vault with no evidence of blood or melena.  Abdominal CT scan shows diffuse colonic dilation with nondilated small bowels.  Leukocyte count is normal and testing for Clostridioides (formerly Clostridium) difficile is negative.  Which of the following most likely contributed to this patient's current condition?

Quizplus · Accepted Answer

11ec25c8_d881_44ba_bc81_3b2d8478c0c2_MD0003_00 This patient's presentation with abdominal distension and colonic dilation on CT scan is consistent with acute colonic pseudoobstruction (Ogilvie syndrome). His diuretic use and recent diarrhea (due to foodborne gastroenteritis) likely caused an electrolyte imbalance (eg, hypokalemia, hypomagnesemia), which can precipitate Ogilvie syndrome. The disorder may largely result from autonomic disruption of the colon. Accordingly, other common causes include severe trauma, severe infection, or major surgery (increased sympathetic drive relative to parasympathetic); neurologic disorders (eg, dementia, stroke, multiple sclerosis, Parkinson disease); and certain medications (eg, anticholinergics). Patients typically have severe abdominal distension, pain, vomiting, and obstipation (inability to pass stool or gas). The abdomen is often tympanic and exhibits hypoactive bowel sounds on auscultation. Abdominal plain films reveal colonic dilation (usually predominantly affecting the proximal colon) with normal haustral markings and a nondilated small bowel. CT scan provides diagnostic confirmation showing colonic dilation with no anatomic obstruction. Management involves bowel rest (NPO) and placement of nasogastric and rectal tubes for colonic decompression. Neostigmine can be given intravenously if symptoms fail to improve after 48 hours or if the cecal diameter on imaging exceeds 12 cm (which is a strong predictor of impending perforation). (Choice A) An endoluminal mass can lead to mechanical colonic obstruction; however, symptoms of obstipation and abdominal distension tend to develop less abruptly than in Ogilvie syndrome. In addition, this patient's CT scan would likely demonstrate a mass if it were large enough to cause obstruction. (Choice B) Colonic hypoperfusion leads to ischemic colitis, which usually presents with hematochezia and abdominal pain; colonic dilation is not typical. (Choices D and E) Entamoeba histolytica infection presents with hematochezia and liver abscesses and is rarely acquired within the United States. Ulcerative colitis tends to cause hematochezia, abdominal pain, and weight loss. Both E histolytica and ulcerative colitis can precipitate toxic megacolon, but one would expect signs of sepsis (eg, fever, leukocytosis) in addition to colonic dilation if this were present. Educational objective: Acute colonic pseudoobstruction (Ogilvie syndrome) typically presents with severe abdominal distension, pain, vomiting, and obstipation. Common causes include electrolyte imbalance (eg, hypokalemia, hypomagnesemia) and factors that lead to autonomic disruption of the colon (eg, major surgery, neurologic disease, anticholinergic medication). The diagnosis is made by CT scan showing colonic dilation without anatomic obstruction, and treatment involves bowel rest and colonic decompression, sometimes aided by intravenous neostigmine. References: Acute intestinal pseudo-obstruction (Ogilvie's syndrome). (http://www.ncbi.nlm.nih.gov/pubmed/20011348)

A 67-Year-Old Man Comes to the Emergency Department Due to Abdominal