The epidemiology of deep vein thrombosis among the people in society who are otherwise well at the time of diagnosis of DVT, is not known. The diagnosis is difficult to make and often not made at all, since symptoms can be vague and misleading and so unapparent that people ignore them. If a person presents with edema and pain in the lower extremity and says it began approximately 2 days ago, there is the strong possibility that the thrombus is not totally acute, even if the clinical presentation is. Thrombogenesis is a dynamic process in flux with thrombolysis. The balance of these two forces is complex and in concert with anatomy, activity and hydration status.
Many factors influence the formation of clot and the routing of venous blood through an extremity.
But, it may require an increase in symptoms and signs because, with overnight rest or periodic elevation, people learn that pain and edema subside. Thus, a trip to the doctor may be postponed. It is the severity of the symptoms or the persistence of symptoms that brings patients to medical attention for clinical diagnosis, objective confirmation of DVT with venography or ultrasound and then treatment. Accepted therapy for DVT as already stated, continues to be bedrest, IV heparin and then coumadin. Duplex studies have shown that thrombus can propagate in patients who are systemically anticoagulated with heparin or coumadin.