A 64-year-old man comes to the emergency department due to 2 days of nausea, vomiting, and abdominal distension. The patient has no abdominal pain. He has hypertension, hypercholesterolemia, coronary artery disease, and congestive heart failure. The patient also has chronic back pain due to a compression fracture 6 months ago. Medications include aspirin, oxycodone, furosemide, losartan, vitamin D, calcium gluconate, and simvastatin. Temperature is 36.7 C (98 F), blood pressure is 130/70 mm Hg, and pulse is 92/min. The abdomen is distended but soft and nontender. There is no rebound tenderness or rigidity. Bowel sounds are decreased. There is 1+ peripheral edema. Laboratory results are as follows: An electrocardiogram (ECG) shows normal sinus rhythm. Abdominal x-rays show diffuse bowel distension with a gas pattern in the colon and rectum. Which of the following is the most appropriate next step in management of this patient?

Question

A 64-year-old man comes to the emergency department due to 2 days of nausea, vomiting, and abdominal distension.  The patient has no abdominal pain.  He has hypertension, hypercholesterolemia, coronary artery disease, and congestive heart failure.  The patient also has chronic back pain due to a compression fracture 6 months ago.  Medications include aspirin, oxycodone, furosemide, losartan, vitamin D, calcium gluconate, and simvastatin.  Temperature is 36.7 C (98 F), blood pressure is 130/70 mm Hg, and pulse is 92/min.  The abdomen is distended but soft and nontender.  There is no rebound tenderness or rigidity.  Bowel sounds are decreased.  There is 1+ peripheral edema.  Laboratory results are as follows:  An electrocardiogram (ECG) shows normal sinus rhythm.  Abdominal x-rays show diffuse bowel distension with a gas pattern in the colon and rectum.  Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Explanation: Nausea and vomiting with a soft, distended abdomen, decreased bowel sounds, and gaseous distension of small and large bowels shown on x-ray suggest ileus. Presence of gas in the colon and rectum and absence of air fluid levels is evidence against small bowel obstruction. In the absence of obvious obstruction and no history of surgery, metabolic causes of ileus are most likely. small bowel obstruction This patient has hypokalemia, which can cause paralytic ileus. Loop diuretics can produce hypokalemia and hyponatremia. Persistent vomiting may also cause hypokalemia but is usually accompanied by other metabolic abnormalities (eg, hypochloremia, metabolic alkalosis). As this patient has normal chloride and bicarbonate levels, he most likely has loop diuretic-induced hypokalemia. Oral potassium replacement is recommended in patients able to tolerate oral intake. Parenteral potassium replacement is necessary in those unable to tolerate oral intake, such as in this patient with dysfunctional bowel and also in patients with cardiac or neurologic complications of hypokalemia. (Choice A) Gastrointestinal infections can be occasionally complicated by ileus. There is usually preceding diarrhea and leukocytosis. (Choice C) Opioids most commonly cause constipation; they can also occasionally cause/worsen ileus. Methylnaltrexone selectively blocks mu opioid receptors on the gut mucosa without reversing the analgesic effect of opioids. It is used to reverse opioid-induced constipation. This patient does not have constipation as there is gas (not stool) in the colon and rectum. Furthermore, in the presence of hypokalemia, intravenous potassium should be administered first. (Choice D) Spironolactone is used to counter chronic diuretic-induced hypokalemia. It will not increase potassium levels in acute hypokalemia. (Choice E) An abdominal CT is indicated when there is diagnostic uncertainty or when bowel obstruction is suspected. Educational objective: Diuretic-induced hypokalemia is a common complication of antihypertensive/congestive heart failure therapy, especially with loop diuretics. Dysfunctional bowel, as in paralytic ileus, and cardiac and neurologic complications are indications for prompt parenteral potassium replacement. References: A physiologic-based approach to the treatment of a patient with hypokalemia. (http://www.ncbi.nlm.nih.gov/pubmed/22901631)

A 64-Year-Old Man Comes to the Emergency Department Due to 2