Haem: Haemophilia B: Free MSRA Podcast

🎧 Haemophilia B – Genetic Bleeding Disorder Essentials for the MSRA 🧬🩸Welcome to another high-yield deep dive! Today we explore Haemophilia B, also known as Christmas Disease — a rare but important X-linked bleeding disorder caused by Factor IX deficiency. Whether you're revising for the MSRA or preparing for practice, this episode covers everything you need.🧠 What You'll Learn:Definition:• X-linked recessive disorder caused by deficient or dysfunctional Factor IX• Leads to delayed, prolonged bleeding episodesCause & Inheritance:• Mutations in the F9 gene on the X chromosome• Affects males; females are typically carriers• Rare variant: Leyden phenotype (Factor IX rises post-puberty)Epidemiology:• ~1 in 25,000 male births in the UK• 5× less common than Haemophilia A• ~30% arise from new mutations🩺 Clinical Features:Severity Classification:• Severe: <1% Factor IX – spontaneous bleeds• Moderate: 1–5% – bleeding post-minor trauma• Mild: 6–30% – bleeds after major injury or surgerySigns & Symptoms:• Easy bruising• Spontaneous joint bleeds (haemarthrosis)• Excessive bleeding after cuts, vaccines, or dental work• Intracranial haemorrhage in severe cases• Neonatal signs: bleeding after heel pricks or circumcision🔬 Differential Diagnoses:• Haemophilia A (Factor VIII deficiency)• von Willebrand disease• Vitamin K deficiency• Factor IX inhibitors• Liver disease• Platelet disorders• DIC🧪 Investigations:• APTT: Prolonged• PT: Normal• Factor IX assay: Confirms diagnosis & severity• Genetic testing for family counselling• Imaging: CT/MRI for suspected joint or CNS bleeds• Inhibitor screening for recurrent or resistant cases💉 Management Strategy:1. Factor Replacement:• Recombinant Factor IX is first-line• Prophylaxis for severe cases; on-demand for mild/moderate• Target ≥50–100% levels in major bleeds or surgery2. Adjuncts:• Tranexamic acid or similar antifibrinolytics• Desmopressin (DDAVP) NOT effective in Haemophilia B3. Emergencies:• Rapid IV Factor IX – do not delay• FFP or cryoprecipitate if recombinant unavailable4. Surgery/Dental Work:• Preoperative planning with haemophilia centres essential5. Genetic Counselling:• Crucial for families – consider cord blood testing in known carrier pregnancies⚠️ Complications:• Haemarthropathy – joint damage from recurrent bleeds• Intracranial haemorrhage – acute danger in severe cases• Chronic pain, inhibitor development• Historical infections (HIV/Hep B/C) in older patients• Co-morbidities (CVD, diabetes, liver disease) in ageing patients🚀 Outlook & Innovation:• Prognosis is excellent with modern therapy• Prophylaxis preserves joint health and life quality• Gene therapy in trials may reduce or eliminate need for infusions• Recombinant products have eliminated viral transmission risks🧠 Memory Aids:• Prolonged APTT, normal platelets = Factor problem• Factor IX = B = Christmas Disease• Severity Mnemonic: – Severe: <1% – Moderate: 1–5% – Mild: 6–30%• BAD = Brain bleed = Acute Danger📚 Revision Resources:• 📘 Notes: https://www.passthemsra.com/topic/haemophilia-b-revision-notes/• 🃏 Flashcards: https://www.passthemsra.com/topic/haemophilia-b-flashcards/• 📂 Q&A: https://www.passthemsra.com/topic/haemophilia-b-accordion-qa-notes/• 🎯 Quiz: https://www.passthemsra.com/topic/haemophilia-b-rapid-quiz/• 🧪 Practice Quiz: https://www.passthemsra.com/quizzes/haemophilia-b/🌐 Main Sites: https://www.passthemsra.com | https://www.freemsra.com#MSRA #HaemophiliaB #MSRAFlashcards #MSRAHaematology #BleedingDisorders #FactorIXDeficiency #Haemarthrosis #PassTheMSRA #FreeMSRA #GeneticDisorders #XLinked #Paediatrics #MSRARevisionNotes #Haematology