Introduction
In deep vein thrombosis (phlebothrombosis), a blood clot is formed in the leg veins. This clot then closes the vein so that the blood cannot return to the heart at this point. Due to anatomical conditions, thrombosis occurs more frequently in the left leg. In addition to a rare hereditary variant, there are various risk factors that can promote the development of thrombosis in the calf, such as immobilization, advanced age or pregnancy.
What symptoms indicate a calf thrombosis?
In the case of thrombosis – not only in the calf – there are 3 typical symptoms (triad) that can be felt on the affected lower leg. However, this is only true in 10% of cases. These include swelling of the calf, dull pain and blue-livid discoloration (cyanosis).
The affected calf may also become overheated. A feeling of heaviness in the leg and an increased vein pattern on the skin may also occur. If there is also shortness of breath, thoracic pain and dizziness, the emergency doctor should be called urgently, as this may be a pulmonary embolism.
The affected calf may swell. The enlarged calf circumference may be noticeable in comparison to the other calf. If both calves are affected by a thrombosis, both legs may swell and therefore the difference in circumference will no longer be as visible.
The swelling occurs because the blood cannot continue to flow to the heart through the clot closing the vein. This results in congestion with fluid transfer from the vessel to the surrounding tissue. This is also known as edema.
If edema occurs, the skin on the affected leg can be pressed in, leaving a dent for a few seconds. This is best tested on the front of the leg next to the shin. The pain may be crampy or similar to a sore muscle in the affected calf, but it can also be much stronger.
In addition, pressure pain occurs along the affected vein where the clot is located. The compression of the calf can also be painful (so-called calf compression pain or “Meyer’s sign”). If the sole of the foot is pressed, pain may be felt in the sole of the foot. Pain can also occur when the foot is pulled towards the shin – i.e. when the calf muscles are stretched.