📏 Defining Splenomegaly
• Palpable spleen >2 cm below L costal margin is usually abnormal
• Up to 15% newborns, 10% children, 5% adolescents have palpable spleen (normal variant)
• Spleen size decreases relative to abdomen with age
🦠 Infectious Causes (Most Common)
• Viral: EBV (mononucleosis), CMV, HIV, hepatitis
• Bacterial: endocarditis, typhoid fever, brucellosis, tuberculosis
• Parasitic: malaria, toxoplasmosis
• Fungal: histoplasmosis (immunocompromised)
⚠️ Hematologic Causes
• Hemolytic anemias: sickle cell disease, spherocytosis, thalassemia
• Acute splenic sequestration: sickle cell → life-threatening emergency
• Leukemia/lymphoma: splenomegaly + cytopenias + constitutional symptoms
• Extramedullary hematopoiesis: thalassemia major, osteopetrosis
📋 Congestive/Pressure Causes
• Portal hypertension (cirrhosis, portal vein thrombosis) → congestive splenomegaly + varices
• Hepatic vein thrombosis (Budd-Chiari)
• Cystic fibrosis, sarcoidosis, storage disorders (Gaucher, Niemann-Pick)
📌 Decision strategy: Viral infection is most common. Acute painful splenomegaly in sickle cell = sequestration crisis (life-threatening). Pancytopenia suggests hypersplenism or leukemia. Family history of jaundice/cholecystectomy → hemolytic anemia.