Haemophilia - Complications of haemophilia

There are a number of problems someone with haemophilia may develop, and further treatment may be required.

Inhibitors

Inhibitors occur when the immune systems of people being treated with blood clotting factor medication start to regard clotting factors as foreign objects.

The immune system creates proteins called antibodies to block the affects of the clotting factor. These are known as inhibitors.

The inhibitors can make medication used to treat haemophilia less effective, which means it is more difficult to prevent and control bleeding.

An estimated 20-30% of people who have treatment for haemophilia A develop inhibitors, while around 1-3% of people who have treatment for haemophilia B develop inhibitors. They usually develop during the first year of treatment, but they can occur at any time.

Inhibitors are often temporary, but there are ways of managing the problem if it's persistent.

Immune tolerance therapy (ITT)

People with moderate to severe inhibitors are usually advised to try a treatment programme called immune tolerance therapy (ITT).

ITT involves receiving daily injections of either octocog alfa (for haemophilia A) or nonacog alfa (for haemophilia B). Over time, the immune system should begin to recognise the blood clotting factors and stop producing inhibitors.

ITT is carried out on a long-term basis, with most people needing a course of treatment that lasts between 6 and 24 months. ITT is successful in an estimated 80% of cases.

Managing a bleed with inhibitors

In people with inhibitors the original clotting factors are removed, so in the event of a bleed a medication called a bypass agent must be used.

A bypass agent is a separate product that can be used to stop bleeding when inhibitors are still present. If ITT doesn't work, you may need to use bypass agents for the rest of your life.

However, bypass agents can only be used as a response to a prolonged bleeding, not as preventative treatment.

Joint damage

Joint damage can sometimes develop if haemophilia is poorly controlled. Successive joint bleeds can damage cartilage (the soft spongy tissue in joints that acts as a shock absorber) as well as the synovium (a thin layer of tissue that lines the inside of the joint).

The more damaged a joint is, the more vulnerable it is to internal bleeding. This in turn means the joint will become even more damaged and vulnerable to bleeding.

Joint damage is more common in older adults with severe haemophilia because preventative treatments were not available in the past. It's hoped that modern treatments mean children growing up with haemophilia today will not have joint damage.

Surgery can be used to treat joint damage. If the synovium is damaged, it can be removed so new synovium can grow in its place. If a joint is seriously damaged, it may be necessary to replace the whole joint with an artificial one, such as a hip replacement or knee replacement.