Understanding Deep Vein Thrombosis (DVT)

[Applause] [Music] hi this is tom from zero2finals.com in this video i'm going to be going through deep vein thrombosis and you can find written notes on this topic at zero to finals dot com slash dvt or in the vascular surgery section of the zero to finals surgery book so let's jump straight in venous thromboembolism or vte is a common and potentially fatal condition this involves a blood clot or a thrombus developing in the circulation this usually occurs secondary to stagnation of blood and hypercoagulable states which is where the blood is prone to clotting when a thrombus develops in the venous circulation is called a deep vein thrombosis or a dvt once a thrombus has developed it can travel or embolize from the deep veins through the right side of the heart and into the lungs where it becomes lodged in the pulmonary arteries this blocks blood flow to the areas of the lungs and is called a pulmonary embolism or pe if the patient has a hole in their heart for example an atrial septal defect the blood clot can pass through to the left side of the heart and into the systemic circulation if it travels to the brain it can cause a large stroke let's talk about the risk factors there are several risk factors that can put a patient at higher risk of developing a dvt or a pe in many of these situations for example surgery we give patients prophylactic treatment to prevent a venous thromboembolism these risk factors include immobility recent surgery long-haul travel pregnancy hormone therapy with estrogen for example the combined oral contraceptive pill or hormone replacement therapy malignancy or cancer polycythemia which is a raised red blood cell count systemic lupus erythematosus which is an inflammatory condition and thrombophilia which is where the patient is prone to developing blood clots a tom tip for you in your exams when a patient presents with features of a possible dvt or pe ask about risk factors such as periods of immobility surgery or long-haul flights in order to score extra points let's talk about thrombophilias thrombophilias are conditions that predispose patients to developing blood clots there are a large number of these including anti-phospholipid syndrome which is probably the one to remember factor five leiden antithrombin deficiency protein c or s deficiency hyper homocysteine emia prothrombin gene variant and activated protein c resistance a tom tip for you if you remember one cause of recurrent venous thromboembolism remember anti-phospholipid syndrome the common association with antiphospholipid syndrome that you may come across in exams is recurrent miscarriage the diagnosis can be made with a blood test for antiphospholipid antibodies next let's talk about venous thromboembolism prophylaxis or vte prophylaxis every patient admitted to hospitals should be assessed for their risk of venous thromboembolism if they're at an increased risk of vte they should receive prophylaxis unless it's contraindicated prophylaxis is usually with a low molecular weight heparin such as an oxaparin contraindications include active bleeding or existing anticoagulation such as warfarin or a doac anti-embolic compression stockings are also used unless they're contraindicated the main contraindication for compression stockings is significant peripheral arterial disease let's talk about the presentation of a deep vein thrombosis dvts are almost always unilateral bilateral dvts are rare and bilateral symptoms are more likely to be due to an alternative diagnosis such as chronic venous insufficiency or heart failure dvts can present with calf or leg swelling dilated superficial veins tenderness to the deep calf particularly over the side of the deep veins edema or fluid collecting in the leg or ankle and color changes to the leg to examine for leg swelling measure the circumference of the calf 10 centimeters below the tibial tuberosity more than a three centimeter difference between the calves is significant if a patient is presenting with symptoms of a dvt ask questions and examine with a suspicion of a potential pulmonary embolism as well so it's worth asking about shortness of breath palpitations and pleuritic chest pain next let's talk about the well score the wealth score predicts the risk of a patient presenting with symptoms having a dvt or a pe it includes risk factors such as recent surgery and clinical findings such as unilateral calf swelling of more than three centimeters than the other leg you can use an online calculator to calculate the wells score next let's talk about making the diagnosis a d-dimer is a blood test for a dvt that is sensitive meaning that 95 percent of patients who have a dvt will have a raised edema but not specific meaning that many patients with a raised d-dimer will not have a dvt this makes it helpful in excluding venous thromboembolism where there is a low suspicion it's almost always raised if there's a dvt however other conditions can also cause a raised edema such as pneumonia malignancy heart failure surgery and pregnancy it's worth noting it's never worth doing a d-dimer when a patient is pregnant a doppler ultrasound scan of the lag is required to diagnose a deep vein thrombosis the nice guidelines recommend repeating negative ultrasound scans after six to eight days if the patient has a positive d-dimer and the well scores suggest that a dvt is likely this is because the first old sound scan may have been falsely negative a pulmonary embolism can be diagnosed using a ct pulmonary angiogram or ctpa or a ventilation perfusion scan or a vq scan a ctpa is usually the preferred investigation unless the patient has significant kidney impairment or a contrast allergy let's talk about the initial management of a dvt the initial management for a suspected or confirmed dvt or pe is with anticoagulation in most patients the nice guidelines from 2020 recommend treatment dose of pixaban or rivaroxaban this should be started immediately in patients where a dvt or a pe is suspected and there's a delay in getting the scan so the treatment is started before the diagnosis can be confirmed on a scan the treatment can then be stopped if the scan excludes a dvt or a pe the nice guidelines from 2020 recommend considering catheter-directed thrombolysis in patients with a symptomatic ilio femoral dvt and symptoms lasting less than 14 days this involves inserting a catheter under x-ray guidance through the venous system and applying thrombolysis directly into the clot next let's talk about long-term anticoagulation the options for longer term anticoagulation in venous thromboembolism are a douak warfarin or low molecular weight heparin doax are oral anticoagulants that do not require monitoring they were called novel oral anticoagulants or no axe but this has been changed to direct acting oral anticoagulants or doax options are apixaban rivaroxaban a doxaban and debigatron they're suitable for most patients including patients with cancer warfarin is a vitamin k antagonist the target inr for warfarin is between two and three when treating dvts and pes warfarin is the first line in patients with anti-phospholipid syndrome patients with antiphospholipid syndrome also require initial concurrent treatment with low molecular weight heparin low molecular weight heparin is the first line anticoagulant in pregnancy patients with a dvt or a pe should continue anticoagulation for three months if there's a clear reversible cause and then it's reviewed beyond three months if there's an unclear cause where there's recurrent venous long embolism or there is an irreversible underlying cause such as thrombophilia and often this is six months in practice and for three to six months in active cancer and then review next let's talk about inferior vena cava filters inferior vena cava filters are devices inserted into the inferior vena cava they're designed to filter the blood and catch any blood clots that are traveling from the venous system towards the heart and the lungs they act as a sieve allowing blood to flow through while stopping larger blood clots these are used in unusual cases of patients with recurrent pes or in patients that are unsuitable for anticoagulation finally let's talk about investigating patients with an unprovoked venous thromboembolism when a patient has their first episode of a venous from embolism without any clear underlying risk factors we need to consider whether it's been triggered by cancer the nice guidelines from 2020 recommend reviewing the medical history baseline blood results and a physical examination for evidence of cancer the previous guidelines from 2012 recommended routinely considering investigations such as a chest x-ray and a ct of the abdomen and pelvis although this is no longer recommended unless the history and examination findings warrant further investigations in patients with an unprovoked dvt or pe that are not going to continue long-term anticoagulation for example they finish three to six months of treatment and they're due to stop the nice guidelines recommend considering testing for antiphospholipid syndrome which involves checking the antiphospholipid antibodies and considering testing for hereditary thrombophilias but only if they have a first degree relative who's also affected by a dvt or a pe thank you for watching this video if you liked the video left a comment or subscribe to the channel thank you so much it really helps zero to finals is not just a youtube channel there's also a website with detailed notes illustrations and questions an instagram account where new questions are posted every day to help you test your knowledge books flash cards and much more i also have a personal channel where i share my thoughts and tips on learning medicine and you can find links to everything in the description of this video see you next time

Channel: Zero To Finals

Views: 384,709

Keywords: medical, education, medicine, doctor, venous thromboembolism, pulmonary embolism, deep vein thrombosis, vte, dvt, warfarin

Id: POMdvRyxlFw

Length: 12min 52sec (772 seconds)

Published: Sun Oct 31 2021