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Haemophilia

Specialties > Haematology

Background knowledge 🧠

Definition

  • Haemophilia is a genetic disorder characterized by impaired blood clotting due to deficiencies in clotting factors.
  • Primarily affects males (X-linked recessive inheritance).
  • Classified into Haemophilia A (Factor VIII deficiency) and Haemophilia B (Factor IX deficiency).

Epidemiology

  • Haemophilia A: 1 in 5,000 male births globally.
  • Haemophilia B: 1 in 30,000 male births globally.
  • UK prevalence: approximately 6,000 people affected by haemophilia.
  • Equal distribution across all ethnic groups.

Aetiology and Pathophysiology

  • Caused by mutations in the F8 gene (Haemophilia A) or F9 gene (Haemophilia B).
  • X-linked recessive inheritance pattern.
  • Leads to insufficient production or dysfunction of clotting factors VIII or IX.
  • Results in poor clot formation, prolonged bleeding, and spontaneous hemorrhages.

Types

  • Haemophilia A: Factor VIII deficiency; more common (80% of cases).
  • Haemophilia B: Factor IX deficiency; also known as Christmas disease.
  • Severity classification: mild, moderate, severe based on clotting factor activity levels.

Clinical Features 🌡️

Symptoms

  • Spontaneous bleeding (e.g., hemarthrosis, muscle hematomas).
  • Prolonged bleeding after trauma or surgery.
  • Easy bruising.
  • In severe cases, intracranial hemorrhage and gastrointestinal bleeding.

Signs

  • Hemarthrosis: swelling, pain, and limited movement in joints, particularly knees, elbows, and ankles.
  • Muscle hematomas: localized swelling and tenderness.
  • Prolonged bleeding after venipuncture or injections.
  • Signs of anemia due to chronic blood loss (e.g., pallor, fatigue).

Investigations 🧪

Tests

  • Prolonged activated partial thromboplastin time (aPTT).
  • Normal prothrombin time (PT) and bleeding time.
  • Specific clotting factor assays to determine levels of Factor VIII or IX.
  • Genetic testing for mutations in F8 or F9 genes.
  • Prenatal diagnosis possible through chorionic villus sampling or amniocentesis.

Management 🥼

Management

  • Replacement therapy with recombinant clotting factors VIII or IX.
  • Prophylactic treatment in severe cases to prevent bleeding episodes.
  • Desmopressin (DDAVP) for mild Haemophilia A (stimulates release of Factor VIII).
  • Antifibrinolytic agents (e.g., tranexamic acid) for mucosal bleeding.
  • Physical therapy to manage joint damage.

Complications

  • Development of inhibitors (antibodies) against clotting factors.
  • Chronic joint damage (hemophilic arthropathy).
  • Transmission of blood-borne infections (e.g., HIV, hepatitis) from blood products (historical concern).
  • Psychosocial impact, including anxiety and depression.

Prognosis

  • With appropriate treatment, life expectancy approaches normal.
  • Severe haemophilia requires lifelong management.
  • Prognosis improves with early diagnosis and prophylaxis.
  • Advances in gene therapy hold future potential for a cure.

Key Points

  • Haemophilia is an X-linked recessive disorder primarily affecting males.
  • Characterized by deficiencies in clotting factors VIII (A) or IX (B).
  • Management includes replacement therapy, prophylaxis, and managing complications.
  • Regular monitoring and multidisciplinary care are essential.

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Haematology