Differential Diagnosis for Elevated INR in the Context of GI Bleeding

Single Most Likely Diagnosis

• Warfarin overdose or supratherapeutic anticoagulation: This is the most likely diagnosis given the context of an elevated INR (International Normalized Ratio) and GI bleeding. Warfarin is a common anticoagulant that works by inhibiting vitamin K-dependent clotting factors, and an elevated INR indicates an increased risk of bleeding.

Other Likely Diagnoses

• Vitamin K deficiency: Vitamin K is essential for the production of clotting factors in the liver. A deficiency, which can be due to poor diet, malabsorption, or liver disease, can lead to an elevated INR and increase the risk of bleeding.
• Liver disease (cirrhosis, hepatitis): Liver disease can impair the liver's ability to produce clotting factors, leading to an elevated INR. GI bleeding is a common complication in patients with liver disease due to varices or coagulopathy.
• Disseminated Intravascular Coagulation (DIC): DIC is a condition characterized by both widespread clotting and bleeding in the vascular system. It can lead to an elevated INR and is often associated with severe underlying conditions such as sepsis, trauma, or cancer.

Do Not Miss Diagnoses

• Hit by a car or other traumatic injury leading to internal bleeding and subsequent warfarin or other anticoagulant use: Although less common, missing a traumatic injury could be catastrophic. The context of GI bleeding and elevated INR might obscure the initial trauma diagnosis.
• Ingestion of rodenticide (superwarfarin): Rodenticides contain long-acting anticoagulants that can cause a significant elevation in INR and severe bleeding. This diagnosis is critical to identify due to the potential for prolonged anticoagulation and the need for specific treatment.

Rare Diagnoses

• Congenital clotting factor deficiencies (e.g., Factor VII deficiency): These are rare genetic disorders that affect the production or function of specific clotting factors. They can present with an elevated INR and bleeding symptoms, including GI bleeding.
• Acquired clotting factor inhibitors: These are rare antibodies that the body produces against its own clotting factors, leading to an elevated INR and increased risk of bleeding. They can be associated with autoimmune diseases, malignancies, or drug reactions.