Haemophilia in Children

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Haemophilia is a genetic disorder characterised by a deficiency in one of the clotting factors in the blood, leading to impaired blood clotting. The two main types are Haemophilia A (deficiency in Factor VIII) and Haemophilia B (deficiency in Factor IX). It is an X-linked recessive disorder, meaning it predominantly affects males, while females are typically carriers. Haemophilia can lead to prolonged bleeding after injury or surgery and spontaneous bleeding, particularly in joints and muscles.

Aetiology

Haemophilia is caused by mutations in the genes responsible for producing clotting factors:

• Haemophilia A: Caused by a mutation in the F8 gene, leading to a deficiency in Factor VIII.
• Haemophilia B: Caused by a mutation in the F9 gene, leading to a deficiency in Factor IX.
• It is inherited in an X-linked recessive manner, meaning males are more likely to develop the condition, while females are usually carriers.

Pathophysiology

Haemophilia is a bleeding disorder resulting from the deficiency of clotting factors VIII (Haemophilia A) or IX (Haemophilia B). Clotting factors are essential proteins that work with platelets to form blood clots and stop bleeding. In haemophilia, the clotting cascade is disrupted due to the lack of these factors, leading to impaired fibrin clot formation. As a result, individuals with haemophilia experience prolonged bleeding after injury, surgery, or even spontaneous bleeding into joints and muscles, which can cause damage over time.

Risk Factors

• Family history: The most significant risk factor is having a family history of haemophilia or other bleeding disorders.
• Gender: Haemophilia is more common in males due to the X-linked recessive inheritance pattern.

Signs and Symptoms

The severity of symptoms depends on the level of clotting factor deficiency:

• Easy bruising: Children with haemophilia often bruise easily from minor trauma.
• Prolonged bleeding: Bleeding that lasts longer than usual after injuries, surgeries, or dental procedures.
• Spontaneous bleeding: Bleeding that occurs without any apparent cause, particularly in joints (haemarthrosis) and muscles.
• Haemarthrosis: Bleeding into joints, causing pain, swelling, and reduced range of motion. This commonly affects the knees, ankles, and elbows.
• Intramuscular bleeding: Bleeding into muscles can cause pain, swelling, and, in severe cases, compartment syndrome.
• Prolonged nosebleeds (epistaxis): Frequent or prolonged nosebleeds without trauma.
• Blood in urine (haematuria): Occasional bleeding in the urinary tract.

Investigations

Diagnostic investigations for haemophilia include:

• Clotting screen: Prolonged activated partial thromboplastin time (aPTT), which suggests a problem with the intrinsic clotting pathway.
• Factor assay: Measurement of Factor VIII or Factor IX levels to determine the severity and type of haemophilia (mild, moderate, or severe).
• Genetic testing: Can confirm the specific mutation in the F8 or F9 gene and identify carrier status in females.

Management

The management of haemophilia focuses on preventing bleeding episodes and managing acute bleeds:

Preventative (Prophylactic) Therapy:

• Clotting factor replacement: Regular infusions of Factor VIII (for Haemophilia A) or Factor IX (for Haemophilia B) to maintain adequate clotting factor levels and prevent spontaneous bleeding. This is the standard of care for children with severe haemophilia.
• Desmopressin (DDAVP): Used in children with mild Haemophilia A to stimulate the release of stored Factor VIII.

Acute Bleeding Management:

• Clotting factor replacement: Immediate administration of the missing clotting factor to stop bleeding in joints, muscles, or other areas.
• Rest, Ice, Compression, Elevation (RICE): Used to manage bleeding into joints and muscles and reduce swelling.
• Tranexamic acid: An antifibrinolytic medication used to prevent clot breakdown and reduce bleeding during minor procedures or nosebleeds.

Complications:

• Joint damage: Repeated bleeding into joints (haemarthrosis) can lead to chronic pain, deformity, and arthritis.
• Development of inhibitors: Some children with haemophilia develop inhibitors (antibodies) against the replacement clotting factor, making treatment less effective.

Referral and Follow-up:

• All children with haemophilia should be managed by a specialised haemophilia centre with access to multidisciplinary care, including haematology, physiotherapy, and orthopaedics.
• Genetic counselling should be offered to families to discuss carrier status and reproductive planning.

References

1. NICE (2024). Haemophilia: Diagnosis and Management in Children. Available at: NICE Guidance
2. Haemophilia Society UK (2023). Managing Haemophilia in Children. Available at: Haemophilia Society
3. British Medical Journal (2023). Haemophilia in Children: Clinical Management Guidelines. Available at: BMJ