What is Disseminated Intravascular Coagulation (DIC)?

What is Disseminated Intravascular Coagulation (DIC)?

Disseminated intravascular coagulation is an acquired syndrome characterized by widespread intravascular activation of coagulation with loss of localization, leading to simultaneous microvascular thrombosis and life-threatening hemorrhage due to consumption of platelets and clotting factors. 1

Core Pathophysiology

DIC is not a disease itself but rather an intermediary mechanism that always occurs secondary to an underlying disorder. 2, 1 The syndrome involves:

• Systemic coagulation activation with excessive thrombin generation throughout the vasculature, causing widespread clot formation 3, 4
• Consumption coagulopathy as platelets, fibrinogen, and other clotting factors are depleted through ongoing clot formation 1
• Paradoxical bleeding tendency despite the procoagulant state, because clotting factors become exhausted 3
• Endothelial dysfunction which precedes and contributes to the coagulation disorder, particularly significant in sepsis-induced DIC 5, 1

Clinical Presentation Spectrum

Cancer-associated DIC presents in three distinct forms that guide management: 2, 5

• Procoagulant DIC: Excess thrombin generation causes thrombosis in both microvascular and macrovascular fields, most common in pancreatic cancer and adenocarcinomas 2, 5
• Hyperfibrinolytic DIC: Activation of the fibrinolytic system dominates, presenting with bleeding complications, characteristic of acute promyelocytic leukemia and metastatic prostate cancer 5, 6
• Subclinical DIC: Laboratory markers of coagulation activation without obvious clinical manifestations 2, 5

Primary Underlying Causes

The most common triggers include:

• Sepsis is the most frequent cause, with mortality of 24.8% in septic patients who develop DIC according to Japanese nationwide data 5, 1
• Malignancies, particularly pancreatic cancer and adenocarcinomas, which carry very high DIC risk 2, 5
• Trauma and acute liver failure through multiple mechanisms including decreased clearance of activated coagulation factors 5
• Obstetric complications including eclampsia and other pregnancy-related calamities 4, 7

Diagnostic Requirements

A mandatory condition for diagnosing DIC is the presence of an underlying disorder known to be associated with DIC—you cannot diagnose DIC without identifying the trigger. 1

Key laboratory findings include: 1

• Thrombocytopenia from platelet consumption
• Prolonged prothrombin time reflecting consumption of coagulation factors
• Elevated fibrin-related markers (D-dimer, fibrin degradation products) indicating ongoing fibrin formation and breakdown
• Decreased fibrinogen levels in advanced cases, though fibrinogen may initially be normal or elevated as an acute phase reactant

Critical Clinical Implications

• Organ dysfunction develops when microvascular thrombosis becomes sufficiently severe, representing the most serious complication beyond bleeding 1
• The International Society on Thrombosis and Haemostasis recommends screening for sepsis-induced coagulopathy in patients with sepsis, as early detection facilitates therapeutic approaches and improves outcome prediction 5, 1
• Understanding the specific mechanism (procoagulant vs. hyperfibrinolytic vs. subclinical) is crucial because treatment approaches differ fundamentally based on the presentation 5

Common Pitfalls

• Do not overlook subclinical DIC in cancer patients presenting with acute embolic stroke or peripheral embolic events—evaluation should be considered even without obvious bleeding or thrombosis 2
• Assess both thrombotic AND bleeding risk in all cancer-associated DIC patients, as patients with pelvic malignancy and concomitant septic abscess face compounded risks 2
• Endothelial dysfunction precedes the coagulation disorder, so the degree of endothelial involvement varies by underlying disease and should inform your clinical assessment 1