Deep Venous Thrombosis
Deep Venous Thrombosis
Deep Venous Thrombosis (DVT) is a condition wherein a blood clot develops in a deep vein that accompanies an artery, mostly in the lower limbs. Consequently, the clot affects blood circulation. Usually thrombosis sets in when the coagulation function is impaired or imbalanced due to abnormalities in the blood, altered blood flow or damage to the blood vessels. Typically the main veins affected by deep venous thrombosis are inner thigh, calf, groin and lower abdomen. A person suffering from deep vein thrombosis is likely to experience pain and swelling in the affected limbs. The pain in the affected leg can become so severe that the person is unable to bear weight on it. This condition is different from arterial thrombosis where the clot forms in the arteries. The main risk factor associated with deep venous thrombosis is that the clot may break off and travel along the blood stream to lodge itself in the lungs, heart or brain. This disease is usually noticed in adults over 60 years.
Deep Venous Thrombosis - DVT is brought about by reduced blood flow or thickening of the blood. Persons who have undergone surgery and been given anti-clotting drugs are likely to develop this condition. Long car or plane journeys, fractures, birth control pills and surgery are potential conditions that may lead to this disease. Those with a history of polycythemia vera or hypercoagulability are more likely to suffer this condition. One of the potential dangers of deep venous thrombosis is pulmonary embolism. Pulmonary embolism is a serious, life-threatening condition where the embolism blocks or closes the artery in the lung. Another complication of deep venous thrombosis is post-thrombotic syndrome characterized by edema, hyper pigmentation and skin ulceration.
Some of the diagnostic tests that help detect deep venous thrombosis are Ultrasound Doppler, Venography of the legs and D-dimer blood test. The Doppler ultrasound aids in studying the reduced blood flow in the affected limbs. The venogram is a special x-ray that reveals any blood clot that is responsible for obstructed blood flow. Magnetic Resonance (MR) Venography with Gadolinium contrast is considered as a prime imaging modality in the diagnosis of DVT.
The blood tests can reveal the clotting tendency. Heparin is an anticoagulant that has been intravenously given to a patient along with oral Warfarin. These medications cause an increase in clotting time. But careful monitoring is of the essence so as to avoid the risk of hemorrhage.
When an artery in the lungs gets blocked, it is referred to as a medical condition of Pulmonary embolism. This condition can be life threatening. Often deep vein thrombosis (DVT) can lead to pulmonary embolism. The blood clots may originate in any other part of the body such as the arm, pelvis or legs. These clots travel through the bloodstream and enter the pulmonary arteries. Recent surgery or injury can lead to a blood clots. Persons with heart disease or those on estrogen therapy are at increased risk of pulmonary embolism. Typical symptoms experienced by those suffering from pulmonary embolism are chest pain, sudden shortness of breath and rapid heartbeat. A patient might have wheezing and weak pulse. The symptoms of pulmonary embolism depend on the extent and size of clots. Embolus can also be the result of fat from the bone marrow that has escaped into the bloodstream. It can also occur due to air bubbles formed during intravenous infusion or surgery. While large emboli cause considerable distress such as chest pain, smaller ones cause shortness of breath. Patients suffering from pulmonary embolism tend to have cough that produces sputum. There may be bluish discoloration on the skin and pain in the legs. Fainting spells or seizures might occur due to sudden decrease in oxygen-rich blood to the brain and other organs. Bluish tint on the skin (cyanosis) is observed when one or more large pulmonary arteries are obstructed.
Diagnostic procedures to detect pulmonary embolism:
- Chest X-ray helps in identifying any lung infections
- CAT scan
- Perfusion Scan of the lung - This test helps in outlining the blood flow to the lungs and helps in detecting any obstructions.
- V/Q scan involves a a nuclear ventilation-perfusion study of the lungs.
- Pulmonary angiogram involves injection of a special dye into the pulmonary arteries to detect obstructive clots.
- D-dimer test is a test that spots d-dimer molecules released by the clots.
One of the initial steps to help a person suffering from pulmonary embolism is administration of oxygen and analgesics. Oxygen is administered through a nasal cannulae or face mask. Blood clots are treated with anticoagulant drugs like heparin or warfarin. But the duration and dosage of anticoagulants needs to be monitored so that it does not result in bleeding in other body organs. Thrombolysis is a procedure whereby Thrombolytic agents (clot-dissolving agents) are injected into the bloodstream to dissolve existing blood clots. Surgery (Pulmonary embolectomy) is often resorted to for removal of clots.
Plethysmograph is a diagnostic tool that is used to measure flow or pressure. Body plethysmography test involves sitting inside an airtight box and breathing to a particular volume. Blood pressure cuffs are placed around your arm and leg. The patient undergoing plethysmography test must remove clothing on arm and leg and refrain from smoking at least half hour prior to the test. The consequent expansion and decompression of the chest volume allows physicians to rule out any blockages in the limbs as it measures systolic blood pressure. Any abnormal readings can be indicative of arterial occlusive disease, vascular disease or blood clots or even deep venous thrombosis. This test is also referred to as arterial plethysmography and is a vital pulmonary function test. Plethysmography is often used to determine bronchial reactions to histamine or metacholine. But this test is not as accurate as arteriography.