Deep Vein Thrombosis :
When a blood clot develops in one of the deep veins in the body, it is called deep vein thrombosis. Such clots usually develop in the legs and may not cause any noticeable symptoms. In some cases, patients feel pain or swelling in the legs and report changes in skin color or a warm sensation in the location of the clot. The condition is dangerous and potentially lethal since the blood clot can break loose and begin traveling toward the lungs. If the clot reaches the lungs, it can get stuck and block the blood flow. Such a blockage of blood flow is called pulmonary embolism, and it can be life-threatening. Pulmonary embolism can cause shortness of breath and chest pain. Some affected individuals also feel dizzy, cough up blood or faint. These signs should not be ignored and require immediate medical attention.