Thrombosis is the most common kind of vascular disease. Although thrombosis can occur in all vessels, colloquially venous thrombosis (phlebothrombosis) is usually meant, especially of the deep veins of the leg. Arterial thromboses occur significantly less often.
Thrombosis occurs when a blood clot (thrombus) forms on the vascular wall. The veins occlude, the venous valves no longer function properly and blood return is disturbed. Blood congestion is the result.
Most blood clots develop in the deep venous system and manifest themselves through sudden pain in the calf or swelling or heavy legs.
Thrombosis can develop into life threatening pulmonary embolism. That is why it is absolutely essential at the first signs to visit a physician and investigate the cause of the pain.
Pulmonary embolism can be the result of a thrombosis. The congested blood clot detaches itself and is transported by the blood stream-right into the finely branched blood vessels. The blood clot may well lodge there and disturb the oxygen supply to the lungs. Pulmonary embolism is the result. The lungs can no longer totally perform their original function. In some cases pulmonary embolism can lead to death.