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VWD vs Hemophilia A/B — MRCP Part 1

TL;DR

For MRCP Part 1, distinguishing Von Willebrand Disease vs. Hemophilia A/B relies on recognising bleeding patterns, inheritance, and lab findings. VWD presents with mucocutaneous bleeding and platelet dysfunction, whereas haemophilia causes deep tissue bleeding due to factor deficiencies. Focus on APTT, bleeding time, and response to desmopressin—these are repeatedly tested. Mastering this distinction can secure easy exam marks.


Why this matters

Bleeding disorders are a high-yield topic in MRCP Part 1, frequently appearing as clinical vignettes that test your ability to integrate clinical presentation, genetics, and laboratory interpretation.

Rather than memorising isolated facts, the exam expects you to:

  • Identify patterns of bleeding

  • Interpret screening tests

  • Apply pathophysiology logically

If you can differentiate VWD from haemophilia in under 30 seconds, you are exam-ready. Start with the MRCP Part 1 overview and reinforce learning with Free MRCP MCQs.


Core sections

1. Pathophysiology (Exam favourite)

  • Von Willebrand Disease (VWD)

    • Defect in von Willebrand factor (vWF)

    • Leads to impaired platelet adhesion and reduced factor VIII stability

  • Hemophilia A/B

    • Hemophilia A: Factor VIII deficiency

    • Hemophilia B: Factor IX deficiency

    • Affects the intrinsic coagulation pathway

👉 Key concept: VWD = platelet + coagulation defect Hemophilia = coagulation defect only

2. Inheritance patterns

  • VWD → Autosomal dominant (most common type)

  • Hemophilia A/B → X-linked recessive

👉 Exam shortcut:

  • Female patient → think VWD

  • Male patient → think haemophilia

3. Clinical presentation

Feature

Von Willebrand Disease

Hemophilia A/B

Bleeding type

Mucocutaneous

Deep tissue

Examples

Epistaxis, menorrhagia

Hemarthrosis, muscle bleeds

Severity

Mild–moderate

Moderate–severe

Sex distribution

Both sexes

Mostly males

👉 One-liner:

  • VWD = superficial bleeding

  • Hemophilia = deep bleeding

4. Laboratory findings (Most tested)

Test

VWD

Hemophilia

Platelet count

Normal

Normal

Bleeding time

↑

Normal

APTT

Normal or mildly ↑

↑

PT

Normal

Normal

Factor VIII

↓

↓ (A), normal (B)

vWF levels

↓

Normal

👉 Key exam pattern:

  • ↑ bleeding time → VWD

  • Isolated ↑ APTT → haemophilia

5. Diagnostic tests

  • VWD

    • vWF antigen assay

    • Ristocetin cofactor activity (platelet aggregation test)

  • Hemophilia

    • Factor VIII or IX assay

👉 High-yield: Ristocetin test abnormal = VWD

6. Management principles

  • VWD

    • Desmopressin (DDAVP)

    • Tranexamic acid

    • vWF concentrates (severe)

  • Hemophilia

    • Factor VIII/IX replacement

    • Prophylaxis in severe disease

    • Avoid intramuscular injections

👉 Key distinction: Desmopressin works in VWD, not haemophilia


10 High-Yield Points (Rapid Revision)

  1. VWD is the most common inherited bleeding disorder

  2. Hemophilia is X-linked recessive

  3. VWD → mucosal bleeding

  4. Hemophilia → joint bleeding

  5. Platelet count normal in both

  6. Bleeding time ↑ in VWD

  7. APTT ↑ in haemophilia

  8. PT normal in both

  9. Desmopressin treats VWD

  10. Ristocetin test abnormal in VWD


Practical examples / mini-cases

MCQ

A 14-year-old girl presents with heavy menstrual bleeding and frequent nosebleeds. Platelet count is normal. Bleeding time is prolonged. APTT is mildly increased.

What is the most likely diagnosis?

A. Hemophilia AB. Hemophilia BC. Von Willebrand diseaseD. Immune thrombocytopenia

Answer: C. Von Willebrand disease

Explanation

  • Female → suggests autosomal inheritance

  • Mucosal bleeding → VWD

  • Prolonged bleeding time → platelet dysfunction

  • Mild APTT rise → reduced factor VIII stability

👉 Hemophilia typically causes deep bleeding and isolated APTT elevation


Medical student revising coagulation disorders notes for MRCP Part 1 exam preparation

Common pitfalls (5 bullets)

  • Misinterpreting mild APTT elevation in VWD as haemophilia

  • Forgetting platelet count is normal in VWD

  • Missing menorrhagia as a key clue

  • Assuming all bleeding disorders cause hemarthrosis

  • Confusing treatment (DDAVP vs factor replacement)


Study-tip checklist

  • ✔ Memorise bleeding pattern differences

  • ✔ Practise lab interpretation tables daily

  • ✔ Link inheritance to patient gender

  • ✔ Revise treatment differences

  • ✔ Solve MCQs via Free MRCP MCQs

  • ✔ Attempt full papers using Start a mock test

👉 Cross-link suggestion: Pair this topic with platelet disorders and coagulation cascades for integrated revision.


FAQs

1. How do I quickly differentiate VWD from haemophilia in MRCP Part 1?

Look at bleeding type: mucosal bleeding suggests VWD, while joint bleeding suggests haemophilia. Confirm with bleeding time and APTT.

2. Why is APTT increased in VWD?

vWF stabilises factor VIII. Its deficiency reduces factor VIII levels, mildly prolonging APTT.

3. Which condition causes menorrhagia?

Menorrhagia is typical of VWD due to impaired platelet adhesion.

4. Does haemophilia affect platelet function?

No. Platelet function is normal; the defect lies in clotting factors.

5. What is first-line treatment for VWD?

Desmopressin (DDAVP) is first-line in most mild to moderate cases.


Ready to start?

Success in MRCP Part 1 depends on mastering high-yield comparisons like this. Build your foundation with the MRCP Part 1 overview, practise with Free MRCP MCQs, and simulate exam conditions using Start a mock test.


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