S4643 Bleeding Risk on the Fast Track: Severe Diarrhea Triggering Rapid INR Rise

Introduction: Elevated international normalized ratio (INR) commonly indicates coagulopathy related to anticoagulant use, liver disease, or vitamin K deficiency. Diarrhea is a well-known cause of fluid and electrolyte losses, but its role in precipitating coagulopathy is often overlooked. In patients with prolonged or severe diarrhea—particularly the elderly—rapid depletion of fat-soluble vitamins, including vitamin K, can occur resulting in coagulopathy and elevated bleeding risk. Case Description/Methods: A 78-year-old woman with a history of cholecystectomy, and hypothyroidism presented with 10 days of profuse, non-bloody watery diarrhea (>20 episodes/day). She denied fever, travel, sick contacts or new medications. Labs revealed severe hypokalemia (K⁺ 2.7), magnesium 0.5, bicarbonate 6, anion gap 31, creatinine 9.8 (baseline 0.9), normal liver enzymes, and INR 2.3 (previously 1.2). She was admitted to the intensive care unit for acute renal failure and HAGMA, and was treated with fluids and bicarbonate infusion. Her metabolic parameters gradually improved. Upon further GI evaluation, computed tomography revealed an atrophic pancreas; stool studies showed low fecal elastase and osmotic diarrhea, confirming new-onset exocrine pancreatic insufficiency (EPI) despite no prior pancreatitis. She was started on pancreatic enzyme replacement. Autoimmune and infectious workup were unremarkable. Due to persistent diarrhea, a diagnostic colonoscopy was planned to rule out intraluminal or microscopic pathologies, remarkably INR rose to 2.9. Despite 2 units of FFP, INR remained at 2.0. A day later, INR further increased to 3.3. Two doses of intravenous vitamin K normalized INR to 1.3, allowing colonoscopy to proceed without complications. Later other fat soluble vitamins were also found to be depleted. Discussion: While INR elevations from diarrhea have been reported in patients on warfarin, this case emphasizes a rare but serious consequence: coagulopathy due to vitamin K deficiency in a patient not on anticoagulation. Severe diarrhea can impair absorption of fat-soluble vitamins, as seen in our patient. The dramatic response to intravenous vitamin K confirmed acquired deficiency. This case underscores the importance of considering fat-soluble vitamin deficiency in patients with persistent diarrhea, especially when evaluating unexplained coagulopathy in an elderly. Timely identification and correction can prevent bleeding complications and facilitate safe diagnostic procedures.