hey everyone and this is want to talk about haemophilia a and I'm affiliate being we're also going to talk about the differences between the two conditions haemophilia a is a hereditary disorder of secondary hemostasis due to factor 8 deficiency and this leads to the inability to form fibrin clots adequately we're gonna show the coagulation cascade and how that both the hemophilia T's can alter fibrin clot formation human philia a is x-linked recessive condition which means that males are predominantly affected and approximately one in 5,000 males have hemophilia a hemophilia A is on a spectrum of severity there are mild moderate and severe forms of the condition and with disorders of secondary hemostasis like haemophilia a and haemophilia B the presentation often involves delayed bleeding so if there's a cut or there is a surgery with an incision there is not a quick bleed but there's often a delayed process of bleeding other presentations include deep bleeds so deeper structures are more likely to have bleeds and this can often present as spontaneous heme arthrosis or blood within a joint space if you see blood within a joint space for any reason think about the hemophilia is oftentimes these individuals can get humor authorities simply just with walking with severe forms lab investigations generally demonstrate a decreased expression of factor 8 as well as an increased PTT however the PT and INR are normal treatment involves using desmopressin or ddavp for mild forms of haemophilia a ddavp is an analogue of our gene vasopressin in for more severe conditions we can use factor 8 concentrate in trance XM ik acid prophylactically haemophilia B is also a hereditary disorder of secondary hemostasis but this time is due to a factor 9 deficiency so this makes it easy to remember haemophilia a is due to a factor 8 deficiency haemophilia B is due to a factor 9 deficiency a comes before B 8 comes before 9 haemophilia B is also an x-linked recessive condition which means it is a male predominant condition approximately one in 30,000 males have haemophilia B and half of the males with it with this condition have a severe disease form like haemophilia a hemophilia B presents with delayed bleeding deep bleeds and spontaneous heme arthrosis lab investigations show a decreased activity factor 9 in an increased PTT but INR and Pt are otherwise normal treatment of haemophilia B involves factor 9 concentrate and trans exam ik acid so here is the coagulation cascade we're gonna quickly go over the coagulation cascade but if you want more information on the coagulation cascade please check out my coagulation cascade lesson activated factor 7 which is denoted with a little a and tissue factor work together to activate factor 10 - activated factor 10 and I want to just mention that activation of these factors involves proteolytic cleavage of the precursor so when we have activated factor 10 activated factor 10 will proteolytically cleaved small amounts of prothrombin to small amounts of thrombin once we have thrombin thrombin has a wide variety of downstream effects it will activate factors 13 11 8 and 5 so a lot of different downstream effects and I'm going over them very quickly so when we have an activated factor 11 activated factor 11 proteolytically cleaved fact 9 - activated factor 9 and thrombin is already acted on factor 8 to form activated factor 8 and these factors combine to work on all on factor 10 again proteolytically cleaving even more factor 10 - activated factor 10 with the activated factor 5 activated factor 10 proteolytically cleaved large amounts of prothrombin to thrombin thrombin will then act on fibrinogen to produce fibrin and factor 13 will take that soluble fiber in' to make it insoluble fiber but what i want you to really focus on is factor 8 in factor 9 factor 8 deficiency again is haemophilia a in factor 9 deficiencies haemophilia B so you can imagine if you have low levels and low activities of these factors we're not going to get proper fiber and clot formation because we're not getting activations of large amounts of thrombin so that's the reason why we get an inadequate formation of fibrin clots we get platelet plugs but we don't quite get an adequate functioning of secondary hemostasis simply because of deficiency in these two factors so in summary what are some of the similarities and differences between MFE a and haemophilia B haemophilia a and B share certain characteristics in common they are both heritable they are both x-linked recessive which means that they're both male predominant and they both have an increased PTT and they're also both disorders of secondary hemostasis so that means that they all have the same presentation delayed bleeding deep bleeds spontaneous humor throws ease however where they differ is that haemophilia a is due to a factor 8 deficiency it's a more common condition as well so it occurs in about one in 5,000 males and it can be treated with desmopressin for mild forms of haemophilia a factor 8 and transics emic acid haemophilia B is due to a factor 9 deficiency it is a more rare condition so it affects about one in 30,000 males and you use factor nine for treatment and transit semuc acid as well guys I hope you found this lesson helpful this was a lesson on haemophilia a and haemophilia B if he did please like and subscribe for more lessons like this one also check out my other hematology lessons thank you so much for watching and I hope to see you next time