A 56-year-old man is admitted to the intensive care unit due to septic shock from pneumonia and is treated with intravenous fluids, antibiotics, and vasopressors. Four days later, the patient's hemodynamic and respiratory status has improved, but he has worsening anemia with positive stool occult blood. He has had no abdominal pain, nausea, vomiting, hematemesis, diarrhea, or hematochezia. Medical history includes hypertension but no prior gastrointestinal disorders. The patient is a smoker with a 40-pack-year history. Medications are intravenous ceftriaxone and azithromycin. Temperature is 37.2 C (99 F), blood pressure is 110/66 mm Hg, and pulse is 84/min. Physical examination reveals right lung crackles and no abdominal tenderness. Hemoglobin is 10.2 g/dL (12.6 g/dL at admission), platelets are 180,000/mm³, and leukocytes are 12,000/mm³. Which of the following is the most likely cause of this patient's anemia?

Question

Quizplus · Accepted Answer

This patient who developed occult gastrointestinal (GI) hemorrhage days after being admitted to the intensive care unit (ICU) for septic shock likely has a stress-induced ulcer. Stress ulcerations are exceedingly common in patients requiring ICU-level care, and typically develop within hours to days of severe physiologic stress. Risk factors include shock, sepsis, coagulopathy, mechanical ventilation, traumatic spinal cord/brain injury, burns, and high-dose corticosteroids. The etiology is multifactorial and likely includes splanchnic hypoperfusion, reflux of bile salts, and accumulation of uremic toxins that impair formation of the protective mucosal layer around the stomach, allowing for mucosal injury and bleeding. Stress ulcers typically form in the proximal stomach and duodenum and may result in generally painless GI bleeding, which can be occult (eg, anemia, positive fecal occult blood testing) or clinically obvious (eg, melena, hematemesis) with shock. Prophylactic acid suppressive agents (eg, proton pump inhibitors [PPIs], H2 blockers) are a mainstay in the prevention of stress ulcerations. However, they are typically reserved for high-risk patients (eg, bleeding diathesis, prolonged mechanical ventilation, recent GI bleed) due to the potential harms associated with these agents, including pneumonia and Clostridiodes (formerly Clostridium) difficile infection. Patients who develop ulcerations should receive PPIs and close monitoring; endoscopy may be required in those with clinically significant bleeding. (Choice A) Acute colonic ischemia is due to hypoperfusion and usually affects watershed areas (limited collateral flow) in the left colon (eg, splenic flexure, rectosigmoid junction). Therefore, it typically presents with crampy, left-sided abdominal pain and overt hematochezia during or shortly after (<24 hours) episodes of hypotension. (Choice B) C difficile infection is common in hospitalized patients on antibiotics but typically causes watery diarrhea associated with fevers and leukocytosis. Occult bleeding and a marked drop in hemoglobin would be rare. (Choice C) Diverticular disease can cause painless bleeding but typically presents with gross hematochezia rather than occult bleeding. Occult bleeding in the setting of severe illness is more consistent with stress ulceration. (Choice D) Peptic ulcer disease often causes occult bleeding but typically begins with gnawing abdominal pain over weeks to months. The acute onset of bleeding after septic shock is more consistent with stress ulceration. Educational objective: Stress ulceration is common in patients in the intensive care unit and can cause occult or gross gastrointestinal bleeding. Risk factors include shock, sepsis, coagulopathy, mechanical ventilation, traumatic spinal cord/brain injury, burns, and high-dose corticosteroids.

A 56-Year-Old Man Is Admitted to the Intensive Care Unit