HAEMOLYTIC DISEASE CLASSIFICIATION made easy! Case presentation

Haemolytic disease got you split?
Join us for a concise look at at haemolytic disease - complete with classification and case presentation, designed to link physiology to clinical features.
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[@Haani36]

Next level video 🔥🔥🔥

[@riteshchaurasia4953]

Why vwd doesn't activate extrinsic factor too since factor x is also produced..as dic..(since extrinsic and intrinsic both can independently activate common pathway..)

[@riteshchaurasia4953]

Itp ttp and hus do not activate clotting cascade as dic. .why..if u could enlighten me..

[@riteshchaurasia4953]

Does giving fibrinogen in vwd is ok..since it can cause more clotting..!?

[@bunmed3817]

Ill try to answer all 3 questions in one comment
As to why with respect to your question on why ITP does not activate the clotting cascade - ITP occurs due to immune mediated destruction of platelets, usually done by the spleen. Since it is the spleen which is removing the platelets directly the platelets do not clump up nor aggregate and thus it does not activate the clotting cascade. Instead it impairs primary haemostasis as fewer platelets are available to from the platelet plug. TTP and HUS however do activate the clotting cascade - both these diseases as well as DIC belong to the group of conditions known as the Microangiopathic haemolytic anaemias (MAHA). The clots formed have sharp fibrin sheaths and get deposited in small blood vessels where passing erythrocytes are sheared. In each case there is an increased tendency to bleed as the platelets and some clotting factors are used up.
With regards to why VWbD does not activate the extrinsic pathway, VWb disease is a disorder of primary haemostasis. It binds to exposed collagen and allows platelets to bind to it, helping to form the initial platelet plug. In VWbD there is lower or abnormal VWb factor in the blood. As a result there is an issue forming the platelet plug and thus patients have symptoms of primary haemostasis dysfunction such as prolonged epistaxis. However the secondary haemostasis is working fine and can kick in to stop the bleeding a little while down the line. The extrinsic pathway can be activated by things such as trauma where tissue factor is activated, however just having low levels of VWb factor in the blood in itself will not activate the extrinsic pathway
In terms of Fibrinogen in VWbD, from what I understand there is no issue with fibrinogen nor fibrin formation and thus use of fibrin does not form part of the management for stable VWbD, as secondary haemostasis should still be functioning normally.