When a blood vessel is injured, the body uses platelets (also called as thrombocytes) and fibrin to form a blood clot to prevent blood loss. Even when a blood vessel is not injured, blood clots may form in the body under certain conditions. Thrombosis is the formation of a blood clot inside a blood vessel, reducing or blocking the flow of blood in the blood vessels and the areas they serve. A clot that breaks free and begins to travel around the body is known as an embolus.

If the thrombus is large leading to partial blockade of blood flow to a tissue, hypoxia (lack of adequate Oxygen) can occur and metabolic products such as lactic acid can accumulate. A larger thrombus causing a much greater obstruction to the blood flow may result in anoxia (complete lack of Oxygen and infarction) and tissue death.

What causes Thrombosis:

  • Hypercoagulability (thrombophilia): higher levels of coagulation factors in the blood, usually as a result of genetics or disorders of the immune system
  • Injury to the endothelial cells of the blood vessel wall: after trauma, surgery or and infection
  • Abnormal flow of the blood: venous stasis following heart failure or long periods of sedentary behavior

Types of Thrombosis:

  1. Venous Thrombosis: thrombosis in the vein
  • Deep Vein Thrombosis (DVT): Blood clot formation from this type of thrombosis forms deep within the vein and commonly affects the leg vein. The clot goes through the vein and cannot be seen through the skin. Most common sites: calf, pelvis and thigh. Can present as pain, swelling and tenderness in one of your legs and warm skin over the area of the clot.
  • Portal Vein Thrombosis: hepatic portal vein that may lead to decrease blood flow in the liver
  • Renal Vein Thrombosis: thrombus is formed in the vein that drains blood in the kidney
  • Cerebral Venous Sinus Thrombosis: forms in the veins of the brain and can lead to stroke
  • Jugular Vein Thrombosis: seen mostly in hospitalized patient due to intravenous intervention, infection and malignancy.
  1. Arterial Thrombosis: thrombosis in the artery
  • Stroke: thrombosis in the brain arteries causing a rapid decline in the brain function
  • Myocardial Infarction (heart attack): thrombus in the heart vessels causing necrosis of the heart muscle

Risk factors and Prevention:

  • Cigarette smoking: refrain yourself from smoking
  • Overweight: weight reducing exercises and diet.
  • Sedentary lifestyle and behavior: make regular voluntary movements, use of compression stockings, which mechanically support the vein to inhibit the formation of blood clots

Anticoagulants may increase the risk of major bleeding slightly, but has been found to offer a benefit in both the prevention and treatment of thrombosis.

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