Haemophilia is a group of inherited bleeding disorders caused by deficiencies in specific clotting factors. They are characterised by prolonged bleeding, especially into joints (haemarthroses) and muscles. The severity depends on residual clotting factor activity. Early recognition and prophylactic treatment have greatly improved outcomes.

📖 Background

Normal haemostasis requires a cascade of clotting factors to generate fibrin and form a stable clot.
Deficiency of Factor VIII (Haemophilia A), Factor IX (Haemophilia B), or Factor XI (Haemophilia C) leads to impaired clotting.
Severity is classified by clotting factor activity:
- Severe: <1% → frequent spontaneous bleeding.
- Moderate: 1–5% → bleeding after minor trauma.
- Mild: 6–40% → bleeding only after surgery/major trauma.
Most common are Haemophilia A (≈80%) and Haemophilia B (Christmas disease). Haemophilia C is very rare.

📊 Comparison of Haemophilia Types

Feature	Haemophilia A	Haemophilia B	Haemophilia C
Deficient Clotting Factor	Factor VIII	Factor IX (Christmas disease)	Factor XI
Inheritance	X-linked recessive	X-linked recessive	Autosomal recessive (affects ♂ and ♀)
Incidence	~1 in 5,000 male births	~1 in 30,000 male births	Very rare (Ashkenazi Jewish populations)
Symptoms	Spontaneous bleeding into joints (haemarthrosis) & muscles Prolonged bleeding post-surgery or trauma Easy bruising	Similar to Haemophilia A	Milder – bleeding usually after surgery/trauma
Diagnosis	Prolonged aPTT ↓ Factor VIII activity Family history	Prolonged aPTT ↓ Factor IX activity Family history	Prolonged aPTT ↓ Factor XI activity
Management	Recombinant/plasma-derived Factor VIII replacement Prophylaxis in severe disease Desmopressin (DDAVP) in mild cases Tranexamic acid for mucosal bleeds	Factor IX concentrates Prophylaxis in severe disease Tranexamic acid for mucosal bleeds	Factor XI replacement for major surgery Fresh frozen plasma (FFP) Tranexamic acid
Complications	Joint damage from recurrent haemarthroses Inhibitor (antibody) formation against Factor VIII Risk of infection from old blood products (rare now)	Inhibitors against Factor IX (less common) Joint damage, chronic pain	Bleeding in surgery Rare spontaneous bleeding

🩺 Clinical Features

Spontaneous joint bleeds (knees, ankles, elbows) → painful, swollen joints → chronic arthropathy if untreated.
Muscle haematomas causing compartment syndrome or nerve compression.
Prolonged bleeding after dental extraction, circumcision, or trauma.
Intracranial haemorrhage in severe cases 🚨.

🔬 Investigations

Clotting screen: Prolonged aPTT, normal PT, normal bleeding time.
Factor assays: Confirm deficiency of VIII, IX, or XI.
Genetic testing: Useful for carrier detection and prenatal diagnosis.
Imaging: MRI for joint damage, US for haematomas.

💊 Management Principles

Factor replacement: Recombinant factor VIII or IX; plasma-derived if unavailable. For haemophilia C, FFP or FXI concentrate.
Prophylaxis: Regular factor infusions in severe disease to prevent joint damage.
Adjuncts: Tranexamic acid for mucosal bleeds, Desmopressin in mild Haemophilia A.
Avoid: NSAIDs, IM injections (risk of haematoma).
Novel therapies: Emicizumab (monoclonal antibody mimicking FVIII activity) for Haemophilia A.

⚠️ Complications

Joint arthropathy → most disabling long-term issue.
Inhibitor development → refractory bleeding, requires bypassing agents (e.g. recombinant FVIIa).
Transfusion-related infections (hepatitis, HIV) – now rare with recombinant products.
Psychological impact, especially in children and adolescents.

📚 Teaching Commentary

💡 Exam tips: – Isolated prolonged aPTT + bleeding history → think haemophilia. – Haemophilia A vs B cannot be distinguished clinically – only by factor assay. – Haemophilia C = rare, autosomal recessive, usually post-surgical bleeding. – Always mention prophylaxis and inhibitor development in viva/OSCE answers.

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Haemophilia