Disseminated intravascular coagulation (DIC) is best described as:

• A. The coagulation pathway is genetically altered, leading to thrombus formation in all major blood vessels.
• B. An underlying disease depletes hemolytic factors in the blood, leading to diffuse thrombotic episodes and infarcts.
• C. A disease process stimulates coagulation processes with resultant thrombosis, as well as depletion of clotting factors, leading to diffuse clotting and hemorrhage.
• D. An inherited predisposition causes a deficiency of clotting factors that leads to overstimulation of coagulation processes in the vasculature.

Answer: (C)

Disseminated intravascular coagulation is a consumption coagulopathy caused by a trigger that activates coagulation throughout the body. This leads to widespread formation of microvascular clots (thrombosis) and, as clotting factors and platelets are used up, a diminished ability to clot elsewhere, resulting in bleeding. So you see both clotting and hemorrhagic manifestations, with lab signs of prolonged clotting times, low platelets, low fibrinogen, and elevated D-dimer. The description that matches this mechanism states that a disease process stimulates coagulation with thrombosis and depletion of clotting factors, leading to diffuse clotting and hemorrhage. The other options imply genetic or hemolytic processes or hereditary deficiencies, which do not describe DIC.