Evolution of our understanding of the pathophysiology of primary mesenteric venous thrombosis.

Mesenteric venous thrombosis is a rare insidious event that is difficult to diagnose. Approximately half the cases in the past were deemed "primary" or "idiopathic." These cases were also frequently associated with a previous history of thromboembolism and a family history positive for thromboembolism. Inherited hypercoagulable disorders, such as deficiency of protein C, protein S, or antithrombin III, will probably explain many "primary" cases. Prompt diagnosis, especially with modern imaging techniques, and prompt anticoagulant therapy decrease mortality.