## Vitamin K Deficiency in Liver Disease: Diagnosis and Management ### Clinical Presentation This patient has: - **Spontaneous bruising** (bleeding tendency) - **Prolonged PT/INR** (2.8 — abnormal) - **Normal platelet count** (rules out thrombocytopenia) - **Chronic liver disease + malabsorption** (risk factors for vitamin K deficiency) - **FFP-resistant coagulopathy** (suggests vitamin K deficiency, not hepatic synthetic failure alone) ### Pathophysiology of Vitamin K Deficiency **Key Point:** Vitamin K is a **fat-soluble vitamin** essential for **γ-carboxylation of clotting factors II, VII, IX, and X**. Deficiency causes: - Prolonged PT/INR (factors II, VII most sensitive) - Normal aPTT initially (factors VIII, XII unaffected) - Normal platelet count and bleeding time ### Differential: Liver Disease vs. Vitamin K Deficiency | Feature | Vitamin K Deficiency | Hepatic Synthetic Failure | | --- | --- | --- | | PT response to IV vitamin K | **Corrects within 24–48 hrs** | No correction | | FFP response | **May correct transiently** | Temporary correction only | | Platelet count | Normal | Often low | | Factor V level | Normal | Low | | Albumin | Normal | Low | | Bilirubin | Normal | Elevated | **High-Yield:** The **FFP-resistant coagulopathy** in this case suggests **vitamin K deficiency is the primary problem**, not hepatic failure. Vitamin K supplementation is indicated. ### Rationale for Correct Answer **IV vitamin K 10 mg daily for 3 days** is the standard management because: 1. **Rapid correction** of PT/INR within 24–48 hours if vitamin K deficiency is the cause 2. **Parenteral route** (IV/IM) bypasses malabsorption 3. **Daily dosing for 3 days** ensures adequate hepatic storage 4. **Diagnostic value**: If INR corrects, vitamin K deficiency is confirmed; if not, liver synthetic failure is the primary problem **Clinical Pearl:** Always give vitamin K **before** FFP or other blood products in suspected deficiency — it is cheaper, safer, and addresses the root cause. **Mnemonic:** **PIVKA** — Proteins Induced by Vitamin K Absence (elevated in vitamin K deficiency; used as a marker in some labs). ### Why Not Other Options? - **FFP alone** is temporary and does not replenish vitamin K stores - **Warfarin** is contraindicated — it further depletes vitamin K–dependent factors - **Liver biopsy** is not the immediate next step; clinical response to vitamin K guides diagnosis [cite:Harrison 21e Ch 139; KD Tripathi 8e Ch 27]
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