A 52-year-old man with a 10-year history of chronic alcohol use disorder presents with a 2-month history of progressive weakness, epistaxis, and easy bruising. Physical examination reveals jaundice, spider angiomas, and splenomegaly. Laboratory findings: hemoglobin 8.5 g/dL, WBC 3,200/μL, platelets 68,000/μL, INR 1.8, albumin 2.8 g/dL, AST 180 U/L, ALT 45 U/L, total bilirubin 3.2 mg/dL. Bone marrow aspirate shows normocellular marrow with no dysplasia or fibrosis. What is the most likely mechanism of pancytopenia in this patient?

Explanation

## Clinical Context: Cirrhosis with Portal Hypertension This patient has **cirrhosis** (evidenced by jaundice, spider angiomas, elevated transaminases, coagulopathy, hypoalbuminemia) with **splenomegaly**, indicating **portal hypertension**. ## Mechanism of Pancytopenia **High-Yield:** In cirrhosis with portal hypertension, pancytopenia results from **splenic sequestration**, not bone marrow failure. ### Why Splenic Sequestration? 1. **Portal hypertension** → increased splenic blood flow 2. **Splenomegaly** → enlarged splenic red pulp with increased blood pooling 3. **Sequestration** of RBCs, WBCs, and platelets in the enlarged spleen 4. **Bone marrow remains normocellular** (as shown in this case) **Clinical Pearl:** The bone marrow is **normal and normocellular**—this is the key finding that excludes intrinsic marrow disease. If the marrow were hypocellular or dysplastic, the diagnosis would be different. ## Differential Diagnosis in Cirrhosis | Mechanism | Bone Marrow | Spleen Size | Reversibility | |-----------|------------|-------------|---------------| | **Splenic sequestration** | Normal/normocellular | Enlarged | Partial (with shunt/transplant) | | Alcohol toxicity | Hypocellular/aplastic | Normal | Slow (weeks–months) | | Autoimmune | Normal | Variable | Good (with steroids) | | MDS | Dysplastic | Normal | Poor | ## Why Each Mechanism Fits or Doesn't Fit **Splenic sequestration is the answer because:** - Normocellular marrow excludes direct toxic suppression (which causes hypocellularity) - Massive splenomegaly is present (portal hypertension) - The pancytopenia is proportional to the degree of splenomegaly - Platelet count is disproportionately low relative to RBC and WBC (platelets are preferentially sequestered) **Mnemonic:** **SPLEEN-SEQ** = Splenic Pooling → Leukopenia, Erythropenia, Eosinopenia, Neutropenia, Sequestration → Enlarged spleen ## Clinical Correlation In cirrhosis: - **Alcohol toxicity** causes hypocellular marrow (direct suppression) — but this patient's marrow is normocellular - **Splenic sequestration** causes pancytopenia with a normal marrow — **matches this case** - **Autoimmune hemolysis** may coexist but would show elevated reticulocyte count and hyperbilirubinemia (indirect) — not the pattern here ## Management Implication Splenic sequestration-induced pancytopenia in cirrhosis improves with: - Transjugular intrahepatic portosystemic shunt (TIPS) - Liver transplantation - NOT bone marrow stimulation (marrow is already normal)