Leg vein thrombosis
In a thrombosis, a blood clot (or thrombus) forms inside a vessel. If this happens in a vein (vein thrombosis), the clot can become loose and pass through the venous system until it reaches the lungs. There it can clog other blood vessels, which can lead to a pulmonary embolism.
Three essential factors contribute to the formation of a thrombosis: alteration or injury of the vessel wall, a deceleration of the blood flow and an increased clotting tendency of the blood. In situations, which encourage one or more of these factors, the risk of a vein thrombosis rises. This includes operations, injuries or cancerous diseases. Sitting or lying down for long periods of time without using the calf muscles poses the danger of a leg vein thrombosis. The regular movement of the leg muscles helps the veins to uphold the blood flow. If this mechanical pumping aid is missing, the blood flow slows down and clots can form in the deep veins of the leg.
A thrombosis of the deep leg veins is dangerous, because the clot can come loose and cause a pulmonary embolism. Large embolisms located at the centre of the lung can lead to an acute and life-threatening condition. Smaller embolisms, or those in a more peripheral location of the lung can cause a pulmonary infarction and pneumonia.
Heavy legs, swollen or warm lower thighs and pain in the calves or the back of the knee can be symptoms of a vein thrombosis. Because of their unspecific nature, in many cases the thrombosis is only identified after a pulmonary embolism has occured. If those symptoms arise after an operation, air travel or long periods without movement, one should seek out a doctor immediately.
The deep leg vein thrombosis must not be confused with varicose veins, which are superficially widened veins. Caused by an injury of the venous valves, the blood keeps flowing back to the superficial vein. Compared with a thrombosis of the deep leg veins, they pose little risk of a pulmonary embolism.
The symptoms of a pulmonary embolism depend on its severity. They can be acute pain in the chest, loss of consciousness, pain while breathing, loss of breath, fever, cough and bloody sputum.
If a leg vein thrombosis is suspected, specialised examinations of the leg and blood are performed. The diagnose can be ensured using the method of doppler sonography, a special ultrasound scan. To diagnose a pulmonary embolism, blood scans, x-rays and a pulmonary MRI are performed.
The main goal of treatment is to prevent the pulmonary embolism in the first place. Blood diluting medications are used, first intravenously, then in the form of tablets. Depending on the situation, this may be done over a long period of time.
Treatment of a pulmonary embolism depends on its severity. In large embolisms, the embolus has to be removed immediately. This can be done surgically or by dissolution using medication. In any case, blood diluting medications are used. If pneumonia was diagnosed, antibiotics are used as well.