A 52-year-old man with a 10-year history of cirrhosis due to hepatitis C presents to the emergency department with hematemesis and melena. On examination, he is tachycardic (HR 110/min), hypotensive (BP 85/50 mmHg), and has clinical signs of portal hypertension (splenomegaly, ascites, spider angiomas). Laboratory investigations show: Hemoglobin 7.8 g/dL, platelets 45,000/μL, INR 2.8, aPTT 48 s, albumin 2.1 g/dL, total bilirubin 4.2 mg/dL. Upper endoscopy confirms bleeding esophageal varices. Which of the following best explains the coagulation abnormality in this patient?

Explanation

## Coagulation Defect in Cirrhosis: Hepatic Synthetic Dysfunction ### Pathophysiology of Coagulopathy in Cirrhosis **Key Point:** Cirrhosis causes coagulopathy through **impaired hepatic synthesis of clotting factors** (II, V, VII, IX, X) and **vitamin K deficiency** due to cholestasis and malabsorption — NOT consumption or immune destruction. ### Mechanism of Coagulation Abnormality | Factor | Mechanism | Result | |--------|-----------|--------| | **Vitamin K deficiency** | Cholestasis → bile salt malabsorption → impaired fat-soluble vitamin absorption | ↓ Factors II, VII, IX, X (vitamin K-dependent) | | **Hepatic synthetic failure** | Cirrhotic liver cannot synthesize clotting factors | ↓ Factors II, V, VII, IX, X, fibrinogen | | **Platelet dysfunction** | Uremia, splenomegaly, bone marrow suppression | ↓ Platelet count + function | | **Fibrinolysis** | Impaired clearance of tissue plasminogen activator | Increased fibrinolysis | ### Laboratory Pattern in Cirrhosis **High-Yield:** The classic pattern is: - **Prolonged PT/INR** (factors II, VII, IX, X are vitamin K-dependent; VII has shortest half-life, so PT is most sensitive) - **Prolonged aPTT** (factors II, V, IX, X) - **Low platelet count** (splenomegaly + bone marrow suppression) - **Low fibrinogen** (advanced cirrhosis) - **Normal bleeding time** (unless platelet count <50,000/μL) **Clinical Pearl:** In this patient, INR 2.8 and aPTT 48 s reflect **hepatic synthetic failure** — the liver cannot produce adequate clotting factors despite normal vitamin K stores. The prolonged PT is more sensitive than aPTT because factor VII (vitamin K-dependent) has the shortest half-life (4–6 hours) and is depleted first. ### Why Vitamin K Deficiency Is Central 1. **Cholestasis** in cirrhosis impairs bile salt secretion → reduced fat-soluble vitamin absorption 2. **Portal hypertension** causes splenic sequestration of platelets (thrombocytopenia) 3. **Malnutrition** common in cirrhosis → poor dietary vitamin K intake 4. **Antibiotic use** (if any) → loss of gut flora that synthesize vitamin K ### Diagnostic Approach ```mermaid flowchart TD A[Cirrhotic patient<br/>with bleeding]:::outcome --> B{Coagulation abnormality?}:::decision B -->|Prolonged PT/aPTT| C[Hepatic synthetic failure]:::action B -->|Normal PT/aPTT| D[Variceal bleeding from<br/>portal hypertension alone]:::action C --> E{Trial of vitamin K?}:::decision E -->|Corrects PT| F[Vitamin K deficiency<br/>component]:::outcome E -->|No correction| G[Pure hepatic synthetic<br/>failure]:::outcome C --> H[Give FFP or PCC<br/>for acute bleeding]:::action C --> I[Vitamin K 10 mg IV daily<br/>for 3 days]:::action ``` **Key Point:** In acute variceal bleeding with cirrhosis, management is: 1. **Variceal ligation or sclerotherapy** (endoscopic hemostasis) 2. **Octreotide** (splanchnic vasoconstrictor) 3. **Fresh frozen plasma (FFP) or prothrombin complex concentrate (PCC)** to correct coagulopathy 4. **Vitamin K 10 mg IV daily** for 3 days (though response is often limited in advanced cirrhosis) 5. **Antibiotics** (ceftriaxone) for spontaneous bacterial peritonitis prophylaxis **Clinical Pearl:** Correction of INR with FFP/PCC is temporary (6–8 hours) because the underlying hepatic synthetic failure persists. The goal is to achieve hemostasis long enough for endoscopic therapy to work. [cite:Harrison 21e Ch 298]