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THROMBOCYTOPENIA : IDIOPATHIC

What is Thrombocytopenia ?

Thrombocytopenia means too few platelets in the blood. Platelets are tiny cells, smaller than red blood cells. Their job is to plug up small blood-vessels when they are injured and stop the bleeding. Therefore, when there are too few platelets there is excessive bleeding, usually following an injury. There is also a risk of bleeding even without injury. The commonest types of bleeding are bruising, tiny haemorrhages in the skin called purpura, and bleeding gums. Idiopathic means cause unknown, although now we do know the cause. The abbreviation ITP is often used for this condition, standing for idiopathic thrombocytopenic purpura. This separates the condition from thrombocytopenia which sometimes results from other disturbances within the bone marrow.

How does Thrombocytopenia occur ?

Platelets, like other blood cells are produced in the bone marrow. In ITP the bone marrow is producing platelets normally. However, they are being destroyed as the result of an antibody that the person has made against his or her own platelets. The antibody coats the platelets which are then destroyed in an organ called the spleen.

Why does Thrombocytopenia occur ?

Normally antibodies are only made against foreign material, for example, in response to infection, or to certain pollen (as in hay fever). We do not know why antibodies are sometimes made against the body's own platelets. Sometimes this seems to be triggered off by an infection, specially in children. Sometimes it is associated with other autoimmune disorders like systemic lupus erythematosus (SLE) and thyroid disease. In some cases the antibodies disappear and the platelet count returns to normal. Sometimes they persist and thrombocytopenia becomes a chronic problem. Most children and many adults usually recover from ITP within a few weeks, but in some adults the platelet count may not recover completely, i.e. the ITP may become chronic. In chronic ITP the platelet count is not always low enough to cause symptoms and so treatment may not be needed, unless for example an operation is required.

Treatment involved for Thrombocytopenia

Before treating you, more blood tests will be performed, and usually a bone marrow aspiration. These tests allow the typical findings of ITP to be confirmed. At the same time, other causes of a low platelet count can be excluded. The actual treatment depends on several factors, especially on just how low the platelet count is. It also depends on whether severe bleeding is present, and if the disorder is being treated for the first time or has come back again after initially successful treatment. Whatever type of treatment is recommended, frequent checks of your platelet count are needed to monitor the effects of the treatment. If the platelet count is very low, treatment will probably be in hospital until the platelet count has improved. Steroid drugs (usually prednisolone) are usually the first line of treatment. For children many doctors prefer to use intravenous immunoglobin (see below) as the initial treatment. Steroids act by suppressing the formation of the antibody. A response occurs in about three out of every four cases. Sometimes, the thrombocytopenia recurs when the steroid treatment is reduced or stopped. As well as steroids there are a number of other immunosuppressive drugs which suppress antibody production. These can be of benefit in some cases of ITP. Sometimes, the thrombocytopenia does not get better with steroid treatment or recurs when steroids are reduced. The doctor may then recommend an operation to remove the spleen (splenectomy). The spleen is just below the ribs on the left side of the abdomen. In ITP the platelets are destroyed in the spleen. Thus taking out the spleen often improves or cures the thrombocytopenia. Another treatment, intravenous immunoglobulin, is given as a drip lasting a few hours, usually given every day for three to five days. This stops the spleen from destroying the platelets. It is a very safe and effective treatment. However, in chronic ITP the effect may not last for very long. It is often used to raise the platelet count before an operation. Platelet transfusions can be given, but the transfused platelets are destroyed in the same way as the body's own platelets. This is therefore not a very effective approach. In an emergency however, giving large numbers of platelets can help stop bleeding.

During treatment for Thrombocytopenia

Your platelet count will be checked frequently, no matter what type of treatment is being given. If it returns to normal on treatment, then any bruising or bleeding will go away. On the other hand, continued bleeding suggests that the count is still low and that the treatment may need to be changed. The doctor should be told immediately if any unusual symptoms develop. These might be due to internal bleeding. Steroids are usually given only for short periods and so side-effects are uncommon. They may cause a gain in weight, increase in appetite, and a change in mood. An increase in blood pressure or an increase in sugar in the blood can occur. Because of these problems, treatment is usually changed if large doses of steroids are needed to control the platelet count.

After Treatment

The duration of treatment is very variable depending on how quickly the disorder responds to treatment and whether or not it becomes a chronic problem, possibly requiring several kinds of treatment. ITP can recur after any treatment, but this is less likely as time goes on. Sometimes virus infections cause the platelet count to fall again but this is usually temporary. If a splenectomy has been done, you will be more likely to get certain infections. Antibiotics such as penicillin or erythromycin may be prescribed to take every day or to keep handy, in case infection develops. During pregnancy, whether you have ITP currently or even in the past, the antibody against your platelets can cross the placenta (afterbirth). This may cause your baby to be born with a low platelet count, although most unlikely to harm the baby. If the baby does have a low platelet count this can be treated. It will recover by itself as the effect of the antibody wears off.

If Thrombocytopenia is left Untreated

You would be at risk of severe and possibly fatal haemorrhage.

Effects on family of Thrombocytopenia

Family and friends will need to understand that you may have to attend hospital frequently. The duration of treatment is very variable depending on how quickly the disorder responds to treatment, and whether or not it becomes a chronic problem, possibly requiring several kinds of treatment. If the platelet count is low, contact sports should be avoided. If your work involves any risk of injury you may need to be off work for a time. ITP is not an inherited condition and there is no familial tendency to develop the disorder. As mentioned earlier, other conditions (such as thyroid disorders) caused by abnormal antibodies are more likely to occur in you - but also among your family members. Routine screening of family members for these conditions is not usually performed.