A 48-year-old woman with a 10-year history of hepatitis C virus (HCV) infection presents to the emergency department with hematemesis and melena. She is hemodynamically unstable (BP 85/50, HR 118). Upper endoscopy reveals actively bleeding esophageal varices. After stabilization and variceal ligation, the patient is admitted to the ICU. Laboratory tests show: platelet count 65,000/μL, INR 2.1, albumin 2.5 g/dL, total bilirubin 4.8 mg/dL, creatinine 1.8 mg/dL. Abdominal ultrasound with Doppler shows a nodular liver, patent portal vein with flow reversal, and splenomegaly. Which pathophysiological mechanism is MOST directly responsible for the development of esophageal varices in this patient?

Question

Accepted Answer

C. Increased hepatic vascular resistance due to cirrhosis-induced architectural distortion, leading to portal hypertension and collateral formation. ## Pathophysiology of Esophageal Varices in Cirrhosis This patient has **decompensated cirrhosis** with **portal hypertension** manifesting as life-threatening variceal hemorrhage. ### The Mechanism of Variceal Formation **Key Point:** Esophageal varices develop as a direct consequence of **portal hypertension**, which arises from increased hepatic vascular resistance in cirrhosis. ### Stepwise Pathophysiology ```mermaid flowchart TD A[Chronic HCV infection]:::outcome --> B[Progressive hepatic inflammation and fibrosis] B --> C[Cirrhosis: architectural distortion and nodule formation]:::outcome C --> D[Increased hepatic vascular resistance]:::outcome D --> E{Portal pressure elevation
Normal: 5-10 mmHg
Cirrhosis: >12 mmHg}:::decision E -->|Portal hypertension| F[Splanchnic vasodilation
Increased portal blood flow]:::action F --> G[Opening of portosystemic collaterals]:::action G --> H[Esophageal varices formation]:::outcome H --> I[Variceal rupture and hemorrhage]:::urgent ``` ### Why Cirrhosis Increases Hepatic Vascular Resistance **High-Yield:** In cirrhosis, the normal liver architecture is replaced by: 1. **Fibrous septa** that distort the sinusoidal network 2. **Regenerative nodules** that compress and obstruct blood flow through hepatic sinusoids 3. **Loss of fenestrations** in sinusoidal endothelium, increasing vascular resistance 4. **Endothelial dysfunction** with reduced nitric oxide (NO) production → increased vasoconstriction This architectural remodeling increases **hepatic vascular resistance**, raising portal pressure above the critical threshold of 12 mmHg (normal: 5–10 mmHg). ### Portal Hypertension → Varices **Clinical Pearl:** When portal pressure exceeds 12 mmHg (the **variceal pressure threshold**), portosystemic collaterals open, including: - Esophageal and gastric varices (via left gastric vein → azygos system) - Hemorrhoids (via superior rectal vein → middle/inferior rectal veins) - Caput medusae (via paraumbilical veins) - Retroperitoneal collaterals Esophageal varices are the most clinically significant because they are prone to rupture due to the high pressure gradient and thin mucosa. ### Why the Other Options Are Incorrect | Option | Why It's Wrong | Correct Concept | |--------|---|---| | Encephalopathy → increased ICP | Encephalopathy is a **consequence** of portal hypertension, not the cause of varices. ICP elevation does not cause variceal formation. | Varices form due to portal hypertension, which independently causes encephalopathy via ammonia shunting. | | Thrombocytopenia → bleeding | Thrombocytopenia (from splenic sequestration) contributes to bleeding risk but does **not cause varices to form**. Varices form regardless of platelet count. | Varices form from portal hypertension; thrombocytopenia worsens bleeding once varices rupture. | | Synthetic dysfunction → variceal rupture | Low clotting factors worsen bleeding after rupture but do **not cause varices to form**. Varices exist before synthetic dysfunction manifests. | Portal hypertension causes varices; synthetic dysfunction increases bleeding severity. | **Warning:** Do not confuse the **formation of varices** (portal hypertension) with the **severity of bleeding** (synthetic dysfunction, thrombocytopenia). This question asks about formation. ### Mnemonic for Portal Hypertension Complications **HAVEC** — **H**emorrhage (varices), **A**scites, **V**ariceal bleeding, **E**ncephalopathy, **C**aput medusae. **Key Point:** Portal hypertension (pressure >12 mmHg) is the **single most important factor** in variceal formation. All other complications (coagulopathy, thrombocytopenia, encephalopathy) are secondary. [cite:Harrison 21e Ch 297]

Answer

A. Splenic sequestration of platelets causing thrombocytopenia and bleeding diathesis

Answer

B. Hepatic synthetic dysfunction resulting in decreased production of clotting factors and variceal rupture

Answer

D. Hepatic encephalopathy leading to increased intracranial pressure and shunting of blood to the esophagus

Explanation

Pathophysiology of Esophageal Varices in Cirrhosis

The Mechanism of Variceal Formation

Stepwise Pathophysiology

Why Cirrhosis Increases Hepatic Vascular Resistance

Portal Hypertension → Varices

Why the Other Options Are Incorrect

Mnemonic for Portal Hypertension Complications

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Option	Why It's Wrong	Correct Concept
Encephalopathy → increased ICP	Encephalopathy is a consequence of portal hypertension, not the cause of varices. ICP elevation does not cause variceal formation.	Varices form due to portal hypertension, which independently causes encephalopathy via ammonia shunting.
Thrombocytopenia → bleeding	Thrombocytopenia (from splenic sequestration) contributes to bleeding risk but does not cause varices to form. Varices form regardless of platelet count.	Varices form from portal hypertension; thrombocytopenia worsens bleeding once varices rupture.
Synthetic dysfunction → variceal rupture	Low clotting factors worsen bleeding after rupture but do not cause varices to form. Varices exist before synthetic dysfunction manifests.	Portal hypertension causes varices; synthetic dysfunction increases bleeding severity.