Definition
Blood clots can occlude vessels and thus lead to a number of different diseases and consequences (e.g. pulmonary embolism, heart attack, etc.). Blood clots are caused, for example, by vascular injuries or a slowed flow rate of the blood. They can occur in arteries as well as in veins. Blood clotting disorders and diseases can also lead to the formation of blood clots. Blood clots can be classified more precisely according to their composition and place of origin.
Causes of a blood clot
There are a number of different causes that can lead to the formation of blood clots. Blood clots (“thrombi”) form constantly in our bloodstream. This is not a cause for concern because our coagulation system can usually dissolve these clots itself.
So there is always a balance between the coagulation of the blood and the dissolving of clots. This is important because good coagulation is necessary for example for wound healing. If there are disorders in the coagulation system and risk factors are present, such as smoking, this can lead to abnormally increased coagulation of the blood and thus to the formation of clots that cannot be dissolved again.
These can cause infarcts, embolisms and thromboses. One of the main causes is hereditary thrombophilia. Hereditary thrombophilia is a genetic predisposition that leads to an increased formation of blood clots.
Such predispositions are sometimes associated with an up to 80-fold increased risk of thrombembolic events compared to the genetically unaffected population. These include APC resistance, factor 8 increase, prothrombin mutation, protein C and protein S deficiency and antithrombin deficiency. All these diseases or predispositions interfere with our coagulation system in such a way that the blood coagulates more quickly and clots form.
Other risk factors for the formation of blood clots include
- Obesity
- Lack of exercise or immobilization (e.g. : on long-distance flights, long bus trips)
- Heart Failure
- Serious infectious diseases
- Tumour diseases
- Increased blood coagulation tendency (e.g. after use of artificial joints such as hip TEP or knee TEP)
- Pregnancy or after giving birth
- Diseases associated with increased viscosity (toughness) of the blood, such as polycythaemia vera
- Oestrogen therapy (e.g. hormone replacement therapies in the menopause or contraceptives)
- Smoking (especially in combination with preparations containing estrogen)
- Antiphospholipid syndrome
- Vascular wall changes due to arteriosclerosis
- Favouring factors of arteriosclerosis such as smoking, high blood pressure and diabetes mellitus
Blood clot symptoms
Blood clots can cause a wide variety of symptoms, depending mainly on where the clot has formed or where it has been carried to. This results in very different clinical pictures, each of which is accompanied by a characteristic symptomatology. Some of the most important clinical pictures caused by blood clots are:Various risk factors such as smoking, obesity, high blood pressure and diabetes mellitus cause changes in the coronary arteries, which is called atherosclerosis.
So-called plaques are formed, to which blood platelets (thrombocytes) can attach themselves. Ultimately, this leads to vasoconstriction, which causes the clinical picture of coronary heart disease or, when blood clots come off, leads to complete vascular occlusion (stenosis). This usually leads to a classic heart attack.
The leading symptomatology is called angina pectoris. It manifests itself as acute pain, which is located behind the breastbone. Patients also refer to this as chest tightness or speak of a feeling “as if someone were sitting on their chest”.
Pain radiating into the left arm is also typical. In women, however, the symptoms can also be somewhat more unspecific, so that sometimes only a dull pain in the area of the back or upper abdomen is visible. Furthermore, sweating, nausea, vomiting and a strong anxiety reaction can occur.
Blood clots can settle in the venous system as venous thrombi and lead to vascular occlusion. Typically, this can lead to an occlusion of the deep leg veins, which is known as phlebothrombosis. The affected leg may be dull and painful, swollen and overheated, and show an increased venous drawing.
There is a risk that the blood clot will come loose due to the movement and be carried into the lungs via the venous system. There the thrombus leads to a pulmonary embolism. This manifests itself in acute shortness of breath with a feeling of dizziness and weakness.
The so-called thrombophlebitis is an inflammation of the superficial leg veins caused by blood clots. The inflamed vein is often hardened, palpable, painful under pressure, overheated and reddened. It can be palpated through the skin as a hard strand.
In principle, blood clots can be carried into any organ and lead to small or large vascular occlusions and infarctions. The symptoms depend on the location of the event. For example, occlusion of cerebral vessels with acute neurological deficits and a stroke, or even a splenic vein infarction with unspecific symptoms such as pain in the upper abdomen.
