Types of blood disorder

Non-cancerous blood disorders include aplastic anaemia, sickle cell disease, thalassaemia and autoimmune diseases.

Aplastic anaemia

This is a very rare condition. Around half of all cases are diagnosed in people under 30, (1) but there are two peaks in age, one in people between 10 and 25 and the other in the over-60s (2).

What is it?

In aplastic anaemia, the bone marrow fails and no longer makes any red blood cells, white blood cells or platelets - cells that help the blood to clot (3).

We do not know what causes most cases of aplastic anaemia. Some are caused by a gene fault or mutation that:

• you are born with (4), or
• has developed during your lifetime (5).

Sometimes it is a very unusual reaction to a drug or having a viral infection that causes bone marrow failure (4,5). It can also be caused by exposure to pesticides or industrial chemicals (5).

Symptoms

If you have aplastic anaemia, you have very low levels of blood cells, which causes:

• frequent infections that are hard to get rid of (6)
• bruises, nosebleeds, very heavy periods or other abnormal bleeding (6)
• extreme tiredness, shortness of breath and fast pulse (6,7).

Treatment

The treatment for aplastic anaemia depends on how severely you have it. Sometimes it is mild and your doctor may just monitor your health with regular blood tests (8).

It can just get better on its own (9), but it may also get worse. You will need treatment to suppress your immune system, as this can help blood counts to recover in up to three out of four cases (8). You will also have blood transfusions to top up your red cells and platelets and medicines to try and prevent infections (8,10).

If you are young and fit enough, severe aplastic anaemia is treated with a stem cell transplant using donor cells: an allogeneic transplant. This is also the first option for inherited aplastic anaemia, as suppressing your immune system does not help (8).

Outlook

Overall, around six out of 10 people with aplastic anaemia live for at least five years after diagnosis. With moderate aplastic anaemia, it is nine out of 10. In many cases, the disease gets better and in others, it does not get any worse (11).

With treatment, the outlook can also be good for severe aplastic anaemia, but this depends on your age. This is at least partly because older patients often could not have a stem cell transplant. But younger people also do very well on treatment to suppress the immune system, with nine out of 10 people under 60 living for at least five years (11).

These figures do not mean people only live for five years: many will have been cured. Patients who take part in clinical trials usually have their health monitored for five years after treatment, so ‘five year survival’ is a commonly quoted statistic.

Sickle cell disease

There are around 15,000 people in the UK with sickle cell disease (12). It is often called sickle cell anaemia, or just ‘sickle cell’.

This is a genetic condition present from birth. Anyone can have sickle cell disease, but it is most common in people from African and Caribbean backgrounds (12).

What is it?

Sickle cell disease affects red blood cells. Instead of being round, they can become crescent-shaped, causing a sickle cell crisis. In a sickle cell crisis, the crescent-shaped red cells block small blood vessels and slow blood flow in larger ones, causing a great deal of pain, and other symptoms described below. We do not fully understand what causes a crisis, but we know they can be brought on by (13):

• infection
• stress
• cold
• dehydration, and
• extreme exercise.

You can only inherit sickle cell disease if both your parents carry the sickle cell gene. If you inherit the gene from one parent, that is called having sickle cell trait. You can then pass the gene on to your children, but you do not have the disease yourself (12).

Symptoms

A sickle cell crisis is usually very painful (12,13). It is common to have pain in the bones, chest or abdomen. You may also have (14):

• swollen hands and feet
• swollen abdomen from an enlarged spleen
• tiredness and lack of energy
• frequent infections with a high temperature.

Sickle cell is very variable in how it affects people; we do not really know why (13). Over time, sickle cell can cause complications and organ damage. People with sickle cell have a higher risk of (12):

• stroke
• blindness
• bone damage, and
• acute chest syndrome, causing breathlessness and chest pain.

Treatment

During a crisis, you will need painkillers and oxygen. Your doctor will also treat any known cause of the crisis, such as warming you up or giving you fluids (15).

There are various drugs your doctor can give to try and prevent crises. You may also have regular blood transfusions, to boost levels of normal haemoglobin (15).

The only cure for sickle cell is a stem cell transplant using blood cells from a donor: an allogeneic transplant. This is usually only suggested for children with sickle cell which is proving hard to control. They must also have a relative whose bone marrow is a close match (15).

For children that do not have a close relative who is a match, doctors are testing transplants in clinical trials using stem cells taken from unrelated donors. These are called MUD transplants, which stands for ‘matched unrelated donor’ (16).

Outlook

The outlook for sickle cell has been steadily improving over time. This has been helped by screening babies at birth, so treatment can be started early. There are also now treatments that are better at controlling sickle cell and reducing complications (17).

Statistically, people with sickle cell do not live quite as long, compared to people without the disease. But overall, they are living longer and longer as managing their condition improves (17). Do not forget that statistics always relate to past treatment. Children born now are likely to do even better.

Thalassaemia: beta-thalassaemia

There are two main types of thalassaemia, alpha and beta. They are both genetic conditions that affect the production of healthy red blood cells. We have only included information on beta thalassaemia here, as stem cell transplants for alpha thalassaemia are still regarded as highly experimental.

There are around 1,000 people in the UK with beta-thalassaemia. It is a genetic condition that you have from birth (18). Anyone can have it but it is most common in people from the Mediterranean, Middle East, India, Pakistan, Bangladesh and South East Asia (18,19).

What is it?

Thalassaemia is a type of anaemia. A change in a gene (mutation) means that the bone marrow could not make enough haemoglobin, the protein that carries oxygen in the blood (20).

You can only inherit beta-thalassaemia if both your parents carry a beta-thalassaemia gene. If you inherit the gene from one parent, you are a carrier. You can then pass the gene on to your children, but you do not have the disease yourself (18).

Symptoms

Babies are screened for thalassaemia in the UK, so early treatment will usually prevent a lot of the symptoms (21). Even if it is well controlled, people with thalassaemia are often shorter than average. Iron overload can cause diabetes and other gland disorders (21).

Treatment

If you have beta-thalassaemia, you need blood transfusions every few weeks throughout your life (22,23). A side effect of this is that too much iron builds up in your body. This can cause organ damage so you need medication to remove it(22). This is called chelation therapy (23).

The spleen can become very enlarged with beta-thalassaemia (23,24). Your doctor may suggest a splenectomy operation to remove it. This will reduce the discomfort the enlarged spleen causes, and can mean you do not need transfusions so often (24).

The only cure for beta-thalassaemia is a stem cell transplant (SCT) using blood stem cells from a donor; an allogeneic transplant (23). The patient usually needs to have a relative whose bone marrow is a close match (25). For children that do not have a close relative who is a match, doctors are testing transplants in clinical trials using stem cells taken from unrelated donors. These are called MUD transplants, which stands for ‘matched unrelated donor’(26).

Outlook

People born with thalassaemia usually live a normal lifespan, as long as they have the right treatment (27).

Autoimmune disorders

These are not blood disorders, strictly speaking. They are a group of conditions caused by the immune system becoming over-active and attacking normal body tissues. A wide range of diseases come under this umbrella, including multiple sclerosis (MS), Crohn’s disease and rheumatoid arthritis (28).

There is a wide range of conditions, there is also a wide range of treatments, not all of which are listed here. Stem cell transplants have been investigated as a treatment option when (28):

• the condition is severe
• the condition is not responding to treatment or there is little or no treatment available
• there is a risk of serious organ damage if the condition carries on untreated.

The theory is that an SCT ‘re-boots’ the immune system, which cures the disease. It is been shown to be most help in relapsing remitting MS, Crohn’s disease and a disease called systemic sclerosis (28).

Patients suitable for a stem cell transplant nearly always have their own stem cells given back to them, after chemotherapy to kill off their own bone marrow cells; this is an autologous transplant (28).

Myelodysplastic syndrome (MDS) and myeloproliferative disorders

These are two other groups of conditions that used to be included in the group of blood disorders. As doctors have found out more about these conditions, how they are thought of has changed. They are now often described as cancers or pre-cancers.

Find out more: Myelodysplastic syndrome (MDS) and myeloproliferative disorders.