Which of the following clinical conditions is the MOST common cause of DIC in hospitalized patients in India?

Explanation

## Epidemiology of DIC: Sepsis as the Leading Cause **Key Point:** Gram-negative sepsis is the **single most common cause of DIC** in hospitalized patients globally and in India. It accounts for 40–50% of all DIC cases. ### Why Gram-Negative Sepsis Triggers DIC 1. **Endotoxin (LPS) Release** - Gram-negative bacteria release lipopolysaccharide (LPS) from their cell wall - LPS binds to TLR4 on monocytes and endothelial cells 2. **Tissue Factor (TF) Induction** - Monocytes release TF in response to TNF-α and IL-1 - Endothelial cells also express TF - TF-Factor VIIa complex activates the extrinsic pathway 3. **Thrombin Generation → Microthrombi** - Widespread fibrin deposition in capillaries - Consumption of platelets and clotting factors - Multi-organ dysfunction (MODS) **Clinical Pearl:** Sepsis-induced DIC is often fulminant and carries the highest mortality (50–80%) among all DIC causes. ### DIC Causes: Ranked by Frequency | Rank | Cause | Frequency | Notes | |------|-------|-----------|-------| | **1** | **Sepsis (gram-negative > gram-positive)** | **40–50%** | Most common; high mortality | | 2 | Trauma (especially head injury) | 15–20% | Tissue factor release from damaged tissue | | 3 | Malignancy | 10–15% | APL > solid tumors; cancer cells express TF | | 4 | Acute hemolytic transfusion reaction | 5–10% | Complement activation | | 5 | Obstetric causes (placental abruption, amniotic fluid embolism) | 5–10% | Rare but important | | 6 | Massive transfusion | 5% | Dilutional coagulopathy + TF from RBC transfusions | | 7 | Acute promyelocytic leukemia (APL) | 5–10% | Leukemic cells express TF and cancer procoagulant | **High-Yield:** In India, sepsis (especially from: - Enteric gram-negative organisms (E. coli, Klebsiella) - Meningococcemia - Pneumococcal sepsis - Malaria-associated severe disease ...is the leading cause of DIC in hospitalized patients. ### Why APL Is NOT the Most Common Cause Although **APL is the most common cause of DIC among hematologic malignancies**, it accounts for only 5–10% of all DIC cases because: - APL is relatively rare (2–3% of all AML) - Sepsis is far more common in hospitalized populations - Modern ATRA/arsenic therapy has reduced DIC incidence in APL **Mnemonic:** **STOP** (Sepsis, Trauma, Obstetric, Promyelocytic leukemia) — but **Sepsis** is #1.