Haemophilia A: Diagnosis & Investigations

Feedback00:52 Intro02:00 What is Haemophilia A?03:00 Factor VIII, Pathogenesis of Haemophilia A07:10 Structure of Factor VIII (exam pearl)300kDHeavy (A1 A2, B) + Light Chain (A3, C1, C2) bound by a metal ions *Calcium*A subunits are 30% homologousB subunit (variable region) is cleaved by thrombin to get Factor VIIIaC1 and C2 help bind to VWFGood to r/o VWF10:55 Epidemiology and history taking- X-linked recessiveFactor VIII is (mostly) feminist.....Turners syndrome, Androgen Insensitivity syndrome, Consanguinity etc. can present with HA  Hari talks about cats 50% of severe haemophilia A have an Intron 22 mutation (non-coding)1/3 de-novo mutationsAmount of Factor VIII negatively correlates with severity (less VIII= more severe)21:55 Presentation of Haemophilia ASpontaneous Joint and Muscle bleeds + Op bleedingYounger presentation = more severeSpontaneous ICH in baby/child inc. in birth traumaThink about On/Off recurrent oromucosal bleeding (can become anaemic)30:00 Non-accidental injury in pre-mobile child- check BSH guidance**33:35 DiagnosisFactor VIII < 40 IU/dL in general (units useful to think as percentages- 40%)Mild 6-40%Moderate 1-5%Severe <1%, presents < 2 yo and diagnosed < 4 yo35:50 InvestigationsBleeding and Family HxFBC, PT/APTT (expect normal PT, abnormal APTT correcting with mixing studies)severe  eg. APTT 100moderate eg. APTT 60-100Factor VIII, IX, XI , XII assay (intirnsic)1 stage and 2 stage chromogenic assay VWF assay (antigen and activity)VW Factor VIII binding assay to r/o VWF 2MGenetic testing (HCDO)- mutational analysis. Can inform likelihood of inhibitor formation and **female carrier identification**Factor V and VIII can be co-inherited in an autosomal inherited pattern*** Biggest cause of death is intracranial death ****** Biggest cause of disability is target joint deformation ***47:52 Summary  'Basics to Brilliance: Haematology Podcast' has been accredited for CPD credit by the Royal College of Pathologists UK. Medical professionals and clinical scientists holding career-grade positions, who are registered with any of the Royal Colleges for CPD, will be eligible to earn 1 credit for every hour of learning. Email: [email protected] Insta: BasicstoBrilliance X: @basics_2_brill Send us your feedback!

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