Question Of The Day #31

This elderly female patient presents to the emergency department with acute onset of severe abdominal pain, vomiting, and diarrhea. Compared to younger patients, abdominal pain in an elderly patient has a higher likelihood of being due to a surgical emergency or from a diagnosis that carries a higher mortality. Elderly patients may have more nonspecific associated symptoms that may make it difficult to confirm a dangerous diagnosis without advanced imaging.  Additionally, elderly patients do not always have a fever or elevated white blood cells during an abdominal infection.  The differential diagnosis of abdominal pain in an elderly patient should be broad and encompass conditions related to many body systems.

The patient in this question has pain that is reported as being significantly high in relation to the minimal amount of abdominal tenderness provoked by the physical exam. This finding, known as “pain out of proportion” should raise concern for an ischemic etiology of the patient’s pain.  Ruptured appendicitis (Choice A) is less likely as the patient lacks clinical signs of peritonitis (i.e. diffuse tenderness with guarding, fever, hypotension, signs of shock).  Appendicitis, although not impossible in an elderly individual, is a diagnosis that occurs more often in younger patients. Ruptured abdominal aortic aneurysm (Choice B) typically results in death rapidly from hemorrhagic shock. This patient lacks signs of shock (hypotension, tachycardia, altered mental status), and her aorta on CT scan is not enlarged or aneurysmal (see image below).  Ureterolithiasis (Choice D), or a stone in the ureter, typically manifests as unilateral intermittent flank pain with hematuria. The question stem does not report a history of prior stones, and a first-time stone at an elderly age is not likely. 

Given the patent’s advanced age, her “pain out of proportion”, acute onset, risk factors for thromboembolic disease (Atrial fibrillation), the most likely diagnosis is acute mesenteric ischemia (Choice C). X-ray imaging can be used prior to CT angiogram imaging, but CT imaging is more specific and sensitive in making the diagnosis.  X-ray imaging may show bowel dilation, ileus, or pneumatosis intestinalis (air in bowel wall) in severe cases.  Lactate and D-Dimer testing can be used in the evaluation of these patients, but neither test is specific for mesenteric ischemia and reliable enough to rule out the disease. CT angiogram imaging of the abdomen and pelvis is the gold-standard diagnostic test for mesenteric ischemia.  Early CT findings include bowel wall thickening (seen on this patient’s imaging), dilated bowel, mesenteric edema, or ascites. Late CT findings include pneumoperitoneum, portal venous gas, and pneumatosis intestinalis.  Treatment of acute mesenteric ischemia is fluid resuscitation, broad spectrum antibiotics, surgical consultation, and consideration for anticoagulation.