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Haemophilia – A Comprehensive Medical Guide

Overview

Haemophilia is a rare, inherited bleeding disorder in which the blood does not clot properly because it lacks sufficient amounts of clotting factor proteins—most commonly factor VIII (haemophilia A) or factor IX (haemophilia B). When a blood vessel is injured, a cascade of clotting factors works together to form a stable clot. In haemophilia this cascade is interrupted, leading to prolonged bleeding after injuries, surgery, or even spontaneously into joints and muscles.

Who it affects – Haemophilia is X‑linked recessive, meaning the defective gene is located on the X chromosome. Since males have only one X chromosome, they are usually affected when they inherit the gene. Females can be carriers and may have mild symptoms if the normal X chromosome is inactivated (lyonisation), but they rarely experience the severe bleeding seen in males.

Prevalence – Worldwide, haemophilia affects roughly 1 in 5,000 to 1 in 10,000 male births.<sup>[1]</sup> Haemophilia A accounts for about 80‑85 % of cases, while haemophilia B makes up the remaining 15‑20 %.<sup>[2]</sup>

Symptoms

Symptoms can vary widely based on the severity of factor deficiency (severe < 1 % activity, moderate 1‑5 %, mild >5‑40 %). Common manifestations include:

• Excessive bleeding after minor cuts or dental work – bleeding that does not stop with pressure.
• Spontaneous joint bleeds (hemarthrosis) – most frequently in knees, elbows, and ankles; leads to swelling, warmth, and limited movement.
• Muscle hematomas – painful, enlarging bruises that may compress nerves.
• Prolonged nosebleeds (epistaxis) – especially in moderate to severe disease.
• Bleeding gums – after brushing or minor trauma.
• Prolonged bleeding after circumcision or vaccination – a key early clue in infants.
• Blood in urine or stool – indicates internal bleeding.
• Hematuria (blood in urine) – may follow bladder trauma.
• Intracranial hemorrhage – rare but life‑threatening; can present with severe headache, vomiting, or loss of consciousness.
• Bruising (purpura) without known cause – often large, irregular, and painful.

In mild haemophilia, symptoms may only become apparent after surgery or significant trauma, whereas severe forms often present in early childhood with frequent joint bleeds.

Causes and Risk Factors

Genetic Causes

Haemophilia is caused by mutations in the F8 gene (factor VIII) for haemophilia A or the F9 gene (factor IX) for haemophilia B. These mutations can be:

• Point mutations, deletions, or insertions that reduce or abolish factor production.
• Large gene rearrangements (especially in severe haemophilia A).

Because the disorder is X‑linked recessive, a mother who carries the defective gene has a 50 % chance of passing it to each son (who will be affected) and a 50 % chance of passing the carrier status to each daughter.

Acquired Haemophilia

Rarely, individuals without a genetic defect develop auto‑antibodies that neutralize factor VIII (acquired haemophilia A). This is most common in older adults (median age 65) and can be associated with autoimmune diseases, malignancies, pregnancy, or certain medications.<sup>[3]</sup>

Risk Factors

• Male sex (due to X‑linked inheritance).
• Having an affected male relative (brother, uncle, grandfather).
• Being a carrier female – carriers can occasionally exhibit mild symptoms.
• Presence of factor inhibitors (antibodies) – develop in up to 30 % of patients with severe haemophilia after repeated exposure to replacement factor.

Diagnosis

Diagnosis is based on clinical suspicion and laboratory testing.

Screening Tests

• Activated Partial Thromboplastin Time (aPTT) – prolonged in haemophilia because it measures the intrinsic pathway where factor VIII and IX act.
• Prothrombin Time (PT) – usually normal because the extrinsic pathway is unaffected.
• Platelet count and function tests – normal in haemophilia, helping to rule out platelet disorders.

Specific Factor Assays

Once a prolonged aPTT is identified, quantitative assays for factor VIII or IX activity are performed. Results are expressed as a percentage of normal activity, which determines severity.

Genetic Testing

DNA analysis of F8 or F9 confirms the mutation, guides carrier testing for family members, and assists in prenatal diagnosis.

Inhibitor Screen

For patients receiving factor concentrates, the Bethesda assay detects neutralizing antibodies (inhibitors). Presence of inhibitors changes treatment strategy dramatically.

Diagnostic Criteria Summary

1. Clinical history of bleeding disproportionate to injury.
2. Prolonged aPTT with normal PT.
3. Reduced factor VIII or IX activity.
4. Confirmation by genetic testing (optional but recommended for family counseling).

Treatment Options

Treatment aims to stop bleeding, prevent future bleeds, and maintain joint health. Therapy is individualized based on severity, lifestyle, and the presence of inhibitors.

Replacement Therapy

• Plasma‑derived factor concentrates – derived from human plasma; e.g., Humate‑P (VIII) or Alphanate (IX).
• Recombinant factor concentrates – synthetically produced; e.g., Advate®, Elocta® (VIII), or BeneFix® (IX). Recombinant products have reduced risk of viral transmission.
• Prophylactic regimen – regular infusions (2–3 times per week for severe haemophilia) to maintain factor levels above 1 % and prevent joint bleeds.

Bypassing Agents (for Inhibitors)

• Activated prothrombin complex concentrate (aPCC; FEIBA) – contains activated clotting factors that bypass the need for factor VIII/IX.
• Recombinant activated factor VII (rFVIIa; e.g., NovoSeven®) – directly activates factor X, leading to thrombin generation.

Emerging Therapies

• Emicizumab (Hemlibra®) – a bispecific monoclonb that mimics factor VIII activity; subcutaneous injection weekly or monthly; effective even in patients with inhibitors.
• Gene therapy – adeno‑associated virus (AAV) vectors delivering functional F8 or F9 genes show promise; approved in the US/EU for selected adults with severe haemophilia A and B (e.g., valoctocogene roxaparvovec).

Adjunctive Measures

• Antifibrinolytics – tranexamic acid or epsilon‑aminocaproic acid used for mucosal bleeds (e.g., dental procedures, epistaxis).
• Physical therapy – early, supervised joint range‑of‑motion exercises to preserve mobility and reduce arthropathy.
• Vaccinations – Hepatitis A & B, influenza, COVID‑19; essential because some patients receive plasma‑derived products.

Living with Haemophilia

Daily Management Tips

• Keep a bleeding diary – record bleed sites, severity, and treatment response.
• Carry a treatment kit – factor concentrate, tourniquet, and clear instructions for self‑infusion.
• Educate family, school, and coworkers on emergency steps and how to obtain factor quickly.
• Maintain a healthy weight – excess weight stresses joints already vulnerable to bleed‑related damage.
• Use protective gear during sports; low‑impact activities (swimming, cycling) are preferable.
• Avoid medications that impair clotting – aspirin, non‑steroidal anti‑inflammatory drugs (NSAIDs), and certain herbal supplements.
• Regular follow‑up – at least annually with a haemophilia treatment center (HTC) for factor level monitoring, inhibitor testing, and joint imaging (MRI or ultrasound).

Psychosocial Support

Living with a chronic bleeding disorder can cause anxiety, depression, or social isolation. Mental‑health counseling, peer‑support groups, and patient‑advocacy organizations (e.g., World Federation of Hemophilia) are valuable resources.

Prevention

While the genetic nature of haemophilia cannot be prevented, the following measures reduce bleed risk and improve outcomes:

• Prophylactic factor replacement – the most effective strategy to prevent joint disease.
• Prompt treatment of minor bleeds – early factor infusion reduces bleed size and joint damage.
• Dental hygiene – regular cleanings with a dentist familiar with haemophilia; use topical tranexamic acid after procedures.
• Injury avoidance – use helmets, shin guards, and padded equipment.
• Vaccinations and infection control – especially hepatitis and HIV screening for those on plasma‑derived products.
• Genetic counseling – for carriers and families planning pregnancy, options include prenatal testing or pre‑implantation genetic diagnosis (PGD).

Complications

If untreated or poorly managed, haemophilia can lead to serious health issues:

• Hemophilic arthropathy – chronic joint bleeding leads to cartilage loss, osteoarthritis, and reduced mobility; reported in 30‑50 % of severe haemophilia patients by age 30.<sup>[4]</sup>
• Inhibitor development – neutralizing antibodies make standard replacement ineffective, increasing bleed risk.
• Life‑threatening hemorrhage – intracranial, intra‑abdominal, or massive hematuria.
• Infections – historically a concern with plasma‑derived products; modern viral inactivation has minimized this risk.
• Chronic pain and disability – secondary to joint disease.
• Psychological impact – anxiety, depression, and reduced quality of life.

When to Seek Emergency Care

References

1. Mayo Clinic. “Haemophilia.” Updated 2023. https://www.mayoclinic.org.
2. World Federation of Hemophilia. “Global Survey of Hemophilia.” 2022. https://www.wfh.org.
3. National Hemophilia Foundation. “Acquired Hemophilia A.” 2024. https://www.hemophilia.org.
4. Cleveland Clinic. “Hemophilic Arthropathy.” Accessed April 2024. https://my.clevelandclinic.org.

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