Blood Clot
One possible cause of pitting edema is venous insufficiency. This occurs when the valves in the veins are not functioning correctly. These valves are responsible for keeping blood flowing in one direction, which is toward the heart. When they don’t work correctly, blood can leak back into the surrounding tissues and cause swelling.
When a person has a blood clot, it can block the flow of blood to the affected area and cause swelling. Blood clots usually develop in veins but can also form in arteries. While both types of clots are serious medical emergencies, those that develop in the veins are generally not as dangerous as those that start in the arteries. This is because veins carry deoxygenated blood back to the heart while arteries carry oxygen-rich blood away from the heart.
If an arterial clot blocks blood flow to the brain, it can result in a stroke, a life-threatening condition. Likewise, if a venous clot blocks blood flow to an extremity, such as an arm or leg, it can cause tissue death.
