Differential Diagnosis for a 36-year-old Female with ATCH 1.4

Single Most Likely Diagnosis

• Vitamin K Deficiency or Warfarin Therapy: This is the most likely diagnosis given the elevated INR (International Normalized Ratio) of 1.4, which suggests an issue with blood clotting. Warfarin is a common anticoagulant that can cause elevated INR levels, and vitamin K deficiency can also lead to coagulopathy.

Other Likely Diagnoses

• Liver Disease: Liver dysfunction can lead to coagulopathy due to decreased production of clotting factors, which could result in an elevated INR.
• Vitamin K Deficiency due to Malabsorption: Conditions like celiac disease or Crohn's disease can lead to malabsorption of vitamin K, affecting blood clotting.
• Early Stages of Disseminated Intravascular Coagulation (DIC): Although less common, early stages of DIC could present with isolated prolongation of INR.

Do Not Miss Diagnoses

• Heparin-Induced Thrombocytopenia (HIT): Although HIT primarily affects platelet count, it's crucial to consider in any patient with recent heparin exposure and signs of thrombosis or coagulopathy.
• Antiphospholipid Syndrome (APS): This autoimmune disorder can cause both arterial and venous thrombosis and may present with laboratory evidence of coagulopathy, including elevated INR in some cases.
• Sepsis or SIRS (Systemic Inflammatory Response Syndrome): Severe infections can lead to coagulopathy, including elevated INR, due to the consumption of clotting factors.

Rare Diagnoses

• Congenital Coagulopathies (e.g., Factor VII deficiency): These are rare genetic disorders that affect the production or function of specific clotting factors, potentially leading to elevated INR.
• Acquired Factor Inhibitors: Autoantibodies against specific clotting factors can lead to coagulopathy, which might present with an elevated INR.
• Amyloidosis: In rare cases, amyloidosis can affect the liver's ability to produce clotting factors, leading to coagulopathy.