Equine Disseminated Intravascular Coagulation Study Guide

Overview and Clinical Importance

Disseminated intravascular coagulation (DIC) is a complex, life-threatening clinicopathologic syndrome characterized by widespread systemic activation of the coagulation cascade, resulting in microvascular thrombosis and subsequent consumption of platelets and coagulation factors. In horses, DIC is always a secondary condition triggered by an underlying primary disease, most commonly gastrointestinal disorders (colic, colitis, strangulating lesions), sepsis, systemic inflammatory response syndrome (SIRS), and endotoxemia.

DIC represents a dynamic continuum ranging from a hypercoagulable (prothrombotic) state with microvascular thrombosis to a hypocoagulable (hemorrhagic) state characterized by consumption of clotting factors and bleeding. Understanding this pathophysiologic spectrum is critical for diagnosis and treatment.

Pathophysiology

The Coagulation Cascade

Understanding the normal coagulation cascade is essential for comprehending DIC pathophysiology. Secondary hemostasis involves two pathways (extrinsic and intrinsic) that converge on a common pathway, ultimately generating thrombin, which converts fibrinogen to fibrin.