When blood clots are formed for reasons other than stopping blood flow from a cut or injury (or they don't end up dissolving as they should after the injury has healed), these clots can produce painful symptoms. They can also be life threatening.
Tenderness, pain, swelling, cramps, warmth, discolouration, redness and inflammation are some symptoms of having a blood clot in the calf. More serious symptoms include infection or death of leg muscle tissue, pulmonary embolism, heart attack and even stroke. The actual symptoms experienced depend on whether the blood clot is in a vein or an artery.
There are two types of peripheral venous disorder (clots formed in the vein). One is varicose veins and the other is deep vein thrombosis (DVT). Varicose veins, the less dangerous of the two, results when a clot damages the valves within a vein, resulting in blood not flowing in the proper direction any longer. It pools in the leg and vein affected instead of making it up to the heart for more oxygenation as it should. This results in pain, swelling and an area warm to the touch, as well as blue discolouration.
Deep Vein Thrombosis (DVT)
DVT clots, which are more life threatening, occur when a part of a clot dislodges from the calf vein and moves up the leg, through the thigh, towards the heart and then the lungs. This embolus (partial clot) flows through the vein, and if it is small enough it will not create any symptoms of concern. However, if medium in size, it could result in possible breathing and chest problems. If large enough, it can cause collapse when it hits the lung (a pulmonary embolism) or even death. Half the people who have DVT never have any symptoms from it. But those who do can generally attribute it to spending extensive periods sitting (in a plane, car or chair); lying immobile (due to recent surgery, injury or illness); or because they were in an accident, or had an injury to the lower body.
Clots that travel from the calf through the coronary and carotid arteries of the body up to the heart and brain can also be life threatening.
Coronary Artery Clots
Artery clots in the calf of the leg will eventually move upward, since they follow the body's normal blood flow direction, if they do not dissolve first. They have the potential if big enough or if the individual has extensive plaque build-up in their heart in that artery to cause a complete blood flow blockage to the heart. This would kill the heart muscle and cause a heart attack.
Carotid Artery Clot
If the clot from the calf makes it through the heart without incident, it could still be life threatening to an individual when it reaches the carotid artery, where it eventually must pass through the brain. If a blockage results due to the clot in the carotid artery, it can result in a mini-stroke or a complete stroke if the brain is cut off from its needed blood supply.