Hypercoagulability: Primary Causes

by Brian Alverson, MD

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    00:01 In this lecture, we’re going to discuss clotting disorders in children.

    00:05 Let’s pause for a moment and re-remember Virchow’s triad.

    00:09 This is the setting in which clots can form inside blood vessels.

    00:13 This happens as a result of blood stasis, through endothelial damage and because of hypercoagulable state.

    00:21 And in this lecture, we’re going to focus a little bit on the hypercoagulable state of children.

    00:26 In general, clots in children are far rarer than in adults.

    00:31 Their endothelial lining is in perfect condition, but they may have a hypercoagulable state that can lead them to form blood clots.

    00:40 So let’s talk about the primary causes of hypercoagulability and the first one I want to talk about is factor V Leiden mutation.

    00:48 Okay.

    00:49 Factor V Leiden mutation is a mutation that causes resistance in the breakdown of factors by protein C.

    00:59 So this is the most common inheritable cause of hypercoagulability and it presents typically in adulthood, not in childhood, but rarely can.

    01:09 This is usually presenting with arterial and venous clots in patients.

    01:16 So another one is antithrombin III deficiency.

    01:22 This is a problem where antithrombin III forms a complex with activated thrombin, factors 10A, 9A, and 11A.

    01:32 Antithrombin III neutralizes these clotting factors and homozygous patients die in utero, but heterozygous patients often have venous thrombosis.

    01:44 And they usually present in the teen years.

    01:46 Another type of hypercoagulability is protein C and S deficiency.

    01:52 If you recall, protein C and S are necessary for breaking down clotting factors VA and VIIIA.

    01:59 Patients who are heterozygous for this condition may present with mild increased risk for clots generally in their second decade of life.

    02:07 However, homozygous patients will present in infancy, specifically in the neonatal period with an entity called neonatal purpura fulminans.

    02:17 This is obviously an incredibly rare condition, but these patients have clots all over through their body and mortality is quite high.

    02:26 Let’s talk about prothrombin mutations.

    02:29 That’s another primary cause of hypercoagulability.

    02:33 In patients with prothrombin mutation, this can result in excess thrombin and formation of clots.

    02:40 There is an increased risk in adulthood, it’s less commonly found in children.

    02:46 Lastly, the MTHFR mutation.

    02:52 The MTHFR mutation is a genetic cause of increased homocysteine in the blood.

    03:00 Basically, it’s a mutation in methylenetetrahydrofolate reductase.

    03:06 This enzyme is responsible for turning homocysteine into methionine.

    03:11 And because it’s not working so well, these patients have a higher level of homocysteine.

    03:16 This results in a blood vessel wall damage and resultingly, a hypercoagulable state.

    About the Lecture

    The lecture Hypercoagulability: Primary Causes by Brian Alverson, MD is from the course Pediatric Hematology.

    Included Quiz Questions

    1. Factor VIII deficiency
    2. Homocysteinemia
    3. Protein C deficiency
    4. Prothrombin mutation
    5. MTHFR mutation
    1. Type-1 Von Willebrand factor deficiency
    2. Factor V Leiden
    3. Antithrombin III deficiency
    4. Protein S deficiency
    5. MTHFR mutation
    1. The most common inherited thrombophilia in individuals with venous thromboembolism
    2. Most commonly presents in early childhood
    3. Common cause of clot formation in arteries
    4. Results in increased activation of protein C
    5. Pregnancy complications are frequent.
    1. Causes reduced inactivation of factors Va and VIIIa
    2. Causes excessive bleeding in severe forms
    3. Most commonly presents in infancy
    4. Prevents warfarin-induced skin necrosis
    5. The homozygous form is more common.

    Author of lecture Hypercoagulability: Primary Causes

     Brian Alverson, MD

    Brian Alverson, MD

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    Excellent lecture
    By Jalil Z. on 10. March 2021 for Hypercoagulability: Primary Causes

    Excellent lecture. Hematology is often poorly explained. This is not the case here. Thanks!