Clinical Features

• Haemophilia A & B
• Mild haemophilia
• Moderate haemophilia
• Severe haemophilia
• Von Willebrand’s disease
• Features of inhibitor
• Other Clotting Factor deficiencies
• Female haemophilia carriers

Haemophilia A and B

People with haemophilia experience bleeding into the tissues of the body after a trivial injury or sometimes spontaneously. The bleeding may occur into joints, muscles, abdomen or the brain. The probability of bleeding and the risk of a severe bleed depends on how little normal clotting factor is produced. This is measured as a percentage of clotting factor produced. A normal person would produce 100% of clotting factor. A person with haemophilia will produce less than this, the lower the percentage the higher the risk of bleeding. This can be used to categorise haemophilia into mild, moderate and severe. These categories refer to the amount of clotting factor produced and not the disability experienced. Severe haemophilia means less than 1% of normal levels of clotting factors are found in the blood.

Disability will depend on how many severe bleeds there have been and whether these have resulted in long term damage.

Mild haemophilia

Clotting factor levels are between 5-25% of normal. Abnormal bleeding tends only to reveal itself after significant injury, surgery or tooth extraction. Treatment of clotting factor deficiency is only required at these times. Life is otherwise normal and joint related or neurological disability from bleeds does not occur.

Moderate haemophilia

Clotting factor levels are between 1-5% of normal. Some moderate haemophilia patients behave as severe haemophilia patients and require prophylactic treatment. In most cases, bleeding tends to occur after trauma or injury, which can be minor but spontaneous bleeding does not usually occur. If not treated, episodes of bleeding may cause joint or neurological damage as described above in severe haemophilia.

Severe haemophilia

People with severe haemophilia experience serious bleeding episodes. The condition usually presents soon after birth, for example with bleeding into the scalp of a newly delivered infant. Bleeding occurs after mild or trivial injury and sometimes spontaneously. Bleeding into joints is a common problem. The joints most commonly affected are the knee, elbow, ankles, shoulder, wrist and hip. Repeated bleeds into joints leads to long term damage in the form of severe arthritis, reduced range of joint movement and sometimes deformity. The long term joint damage rather than the bleeding episodes themselves are the cause of disability. Since the 1990s, prophylactic (preventative) treatment has been introduced to prevent such bleeds and children with severe haemophilia born since then, may escape serious joint damage. Anyone born prior to the 1990s with severe haemophilia is likely to have some joint damage. Many will have multiple affected joints and enduring disability related to this, despite now using prophylactic (preventative) treatment to prevent further bleeds and damage.

Bleeding into tissue causes haematoma formation (a collection of blood). Haematomas can damage surrounding tissue through pressure effects with the brain especially at risk as it is housed in a non-expandable space inside the skull. Haemorrhage into the brain may be life threatening and can cause long term neurological deficits or epilepsy. Haematomas elsewhere in the body can cause muscle damage or peripheral nerve damage. Bleeding into large spaces such as the abdomen can result in extensive blood loss from the circulation and such bleeds are life-threatening.

Frequency of bleeding episodes varies between individuals. Without prophylactic treatment some people experience bleeds several times a week whilst in others, they may occur only a few times a year.

Von Willebrand’s disease

This disease is characterised by a deficiency of von Willebrand factor - another protein involved in the clotting cascade. The severity of the condition varies according to the type of von Willebrand’s and between different individuals. Most people have mild problems with a tendency to nose bleeds, bleeding gums, easy bruising and prolonged bleeding from small cuts and abrasions. Abnormal bleeding may occur with surgical or dental procedures. Women may have heavy periods and become anaemic. Many people have no symptoms and are only diagnosed after routine blood tests or when another member of the family is found to have the condition.

A small minority have a serious bleeding tendency that is comparable to that seen in moderate or severe haemophilia with bleeding into joints and soft tissues. Again, disability, if present, will be related to the long term consequences of this rather than the clotting factor deficiency itself.

Features of inhibitor

Because treatment of bleeds is less effective, multiple large joints are likely to be affected by arthritis from childhood onwards. Pain related to arthritis in the hips, knees and ankles is likely to affect mobility and although joint replacement of individual joints will relieve pain from arthritis and prevent further bleeding into that joint, mobility or range of movement will not improve. A ‘fixed flexion’ deformity of the knee or hip is also likely to reduce mobility as it effectively shortens the affected leg and affects gait. In someone with multiple damaged joints this places further strain on other joints and increases the risk of bleeding when walking.

Aspects of personal care may be difficult if the elbow or shoulder is significantly affected and range of movement in these joints is poor. This is much less common than mobility problems due to lower limb involvement.

Other Clotting Factor deficiencies

People with other deficiencies are likely to have bleeding episodes and disability similar to people with haemophilia in the moderate or severe categories as described above. Again disability is related to joint damage or neurological events secondary to the bleeding and these should be the focus when assessing needs. These conditions are very rare.

Female haemophilia carriers

Abnormal bleeding may occur after surgery or tooth extraction as some carriers will have slightly low levels of clotting factor. The carrier state is unlikely to be recognised unless there is a bleeding event that prompts investigation. Life is normal and there is no associated disability.

Click on the links for details of:

• Causes & assessment of disability
• Clotting Factor replacement therapy
• Complications of Clotting Factor replacement therapy

Amended November 2009