Normally, a person has 150-400 (x 10^9) platelets per liter blood.
In immune thrombocytopenia (abbreviated ITP) the number of platelets are reduced to less than 100 (x 10^9). We say that the platelet count is less than 100.
If the platelet count is very low, spontaneous bleeding may occur and there may be blood under the skin and bruises.
In ITP the antibodies bind to the platelets which are removed from the blood, mainly through the spleen. This means that the number of platelets in the blood is lower than normal.
Normally, the body would be able to increase the production of platelets in order to compensate for the loss, but this function may also be inhibited in an ITP patient.
These two factors, the destruction and the impaired production of platelets, result in clear signs of lack of platelets / thrombocytopenia.
A platelet is a blood cell without a nucleus.
Platelets are fragments of cytoplasm that are derived from the megakaryocytes in the bone marrow. Their size is 2–3 µm in diameter. Their life span is about 7-10 days. Platelets are mainly destroyed in the spleen.
When a bleeding starts, the platelets stick to the injured vessel wall. They clump and plug the vessel breach. Therefore, the platelets play an important role in the process of blood clotting.
The medical treatment aims to increase the platelet count to a level which is considered safe and which will make it possible for the ITP patient to live a largely normal life. There is currently no cure for ITP and relapse may occur even after several years without symptoms.
The initial treatment is often prednisolone or high-dose dexamethasone.
Immunoglobulin (Ivig) is injected into the vein. This causes the number of platelets to rise briefly in most people. The treatment can be repeated.
Anti D. The effect is somewhat like that of immunoglobulin, but it only works in Rhesus positive patients who still have their spleen. Anti D is injected either into the vein or under the skin.
Rituximab is injected into the vein or under the skin. Typically, treatment is given four times with one-week intervals.
About half of the patients benefit from this treatment initially, but most of them relapse within a three year period.
Splenectomy (Surgical removal of the spleen). This is the most effective method with a long-term remission (fully or partially) in more than half of the patients.
However, it is not possible to predict who will benefit from the treatment. For this and other reasons many doctors and patients defer this treatment option until other options have been tried and failed.
