Define Haemophilia. Describe its clinical features, investigations, management and complications.

Definition

• Haemophilia is an X-linked recessive inherited bleeding disorder caused by deficiency of a clotting factor.
• Haemophilia A (factor VIII deficiency) is the commonest; Haemophilia B (factor IX deficiency, 'Christmas disease') is clinically identical.
• It affects males, transmitted by carrier females.

Severity (BY Factor Level)

Clinical Features

• Haemarthrosis — recurrent bleeding into joints (knees, ankles, elbows), causing pain, swelling and, over time, chronic arthropathy and 'target joints'.
• Muscle haematomas and deep soft-tissue bleeds.
• Prolonged bleeding after trauma, surgery, dental extraction or circumcision.
• Intracranial haemorrhage — the most dangerous, life-threatening bleed.
• Bleeding is typically delayed and deep (unlike the immediate, superficial mucocutaneous bleeding of platelet disorders).

Investigations

• Prolonged aPTT (intrinsic pathway) with a normal PT, normal platelet count and normal bleeding time.
• A mixing study corrects the aPTT (factor deficiency) unless an inhibitor is present.
• Specific factor assay (VIII or IX) confirms the diagnosis and grades severity.
• Genetic testing for carrier detection and prenatal diagnosis.

Management

• Factor replacement — factor VIII or IX concentrate, given on-demand for bleeds or as regular prophylaxis in severe disease (to prevent joint damage).
• Desmopressin (DDAVP) — raises factor VIII in mild haemophilia A.
• Antifibrinolytics (tranexamic acid) for mucosal/dental bleeding.
• Acute joint bleed — factor replacement plus rice (rest, ice, compression, elevation) and analgesia.
• Avoid intramuscular injections, aspirin and NSAIDs; immunise (including hepatitis B); manage inhibitor development.

Complications

• Chronic haemophilic arthropathy (the major long-term morbidity) and joint deformity.
• Inhibitor (antibody) development against the factor — makes bleeds hard to treat.
• Transfusion-transmitted infections (historically); life-threatening intracranial/airway bleeds.

Genetics & Inheritance

• X-linked recessive — affected males, carrier females (who may have mildly low factor levels).
• An affected father cannot transmit to sons, but all his daughters are carriers; a carrier mother transmits to 50% of sons (affected) and 50% of daughters (carriers).
• ~⅓ of cases arise from new mutations (no family history).

Differential Diagnosis of a Bleeding Child

Comprehensive Care

• Care in a haemophilia treatment centre with a multidisciplinary team.
• Home therapy and factor prophylaxis; physiotherapy for joints; genetic counselling and carrier testing.
• Regular review for inhibitors and blood-borne infections.

Inhibitors

• Some patients develop antibodies (inhibitors) against infused factor, which neutralise treatment and make bleeds difficult to control.
• Suspected when bleeding fails to respond to adequate factor; managed with bypassing agents and immune-tolerance induction.

Management of Bleeds BY Site

• Joint/muscle bleed — factor + rice + analgesia; avoid aspiration unless necessary.
• Mucosal/dental — factor + tranexamic acid.
• Life-threatening (intracranial, airway, GI) — immediate high-dose factor and urgent assessment.

WHY Prophylaxis?

Regular prophylactic factor in severe haemophilia prevents recurrent joint bleeds and the resulting crippling arthropathy, and is now the standard of care where resources allow.

General Precautions for the Family

• Avoid intramuscular injections, aspirin and NSAIDs; give vaccines subcutaneously with pressure.
• Wear medical-alert identification; seek care early for any significant bleed, especially head injury.
• Encourage safe activity/physiotherapy to protect joints while avoiding high-contact sports.