With thanks to Dr John Grainger and Chloe Goodall for this information.
This page explains about immune thrombocytopenia (ITP), which is a blood problem affecting the platelets. It also explains what to expect when you are diagnosed with the condition.
What are platelets?
Platelets are one of the three types of blood cell, along with red and white blood cells. Platelets are small and sticky and their job is to prevent bruising and stop bleeding after an injury.
Platelets, like red and white blood cells, are formed in bone marrow which is at the centre of big bones, such as the femur and hip. A rough idea of how many platelets are present in the blood (platelet count) can be made using a sample of blood. The normal platelet count is between is 150 to 400 (UK measurement). In most cases of ITP the platelet count is less than 20. A low platelet count is called ‘thrombocytopenia’.
What is immune thrombocytopenia?
Immune thrombocytopenia is a medical term for a condition in which there is bruising (purpura) because there are fewer platelets in the blood than usual (thrombocytopenia) and is usually caused by something going wrong with the body’s defence against infection (immune system) or an allergic reaction of some kind.
How common is ITP and who does it affect?
About four in every 100,000 children develop ITP each year. In teenagers ITP is more common in girls than boys.
Chronic ITP is the term for ITP that has not gone away on its own after 12 months. Only 1 in 5 teenagers and adolescents with ITP will develop chronic ITP with teenage girls at highest risk. The majority of teenagers and adolescents with ITP will still have an improvement of the platelet count even if the ITP persists and the majority of teenagers and adolescents will still completely recover after a few years even if the ITP is still present at 12 months.
What are the symptoms of ITP?
Most teenagers and adolescents with a platelet count of under 20 will have pinprick blood spots under the skin (petechiae) and bruising. Bruising most commonly follows minor knocks ("easy bruising") but may also occur spontaneously without trauma. Apart from the bruising/ bleeding most adolescents are otherwise well. Common sites of spontaneous bleeding are the gums and nose. Girls may be troubled with heavy periods.
Tiredness and depression or other mood changes are commonly reported by people with ITP. This may be due to a change in chemicals which are carried by platelets.
Less common but potentially serious are spontaneous bleeds occurring from the gut or brain. Data from worldwide studies suggests that the risk of serious bleeds is about 3 in 100 and the risk of brain bleeds is about 1 in 300. The risk of serious bleeding is much lower when the platelet count recovers to over 20 x 109/Litre.
What causes ITP?
ITP commonly results from the immune system mistaking platelets as being foreign and attacking them. In many cases this may follow a viral infection or vaccination during which time the immune system attacks the virus but the immune system then goes on to think that the platelets are part of the virus and starts to attack the platelets.
How is ITP diagnosed?
ITP is usually diagnosed using a blood test called a ‘full blood count’. When a sample of your blood is looked at under a microscope, a blood doctor can examine each blood cell type closely. This is to rule out other conditions that may cause similar symptoms to ITP. If the platelets, red blood cells and white blood cells all look normal, this rules out blood cancer (leukaemia). If the low platelet count improves quickly and no treatment is needed, you will not need any further tests.
If the platelet count is not showing signs of recovery by 3 to 6 months then a small sample of bone marrow will need to be taken and looked at under the microscope. Additional blood tests may be taken at this time to rule out rare problems with making blood clots and rare problems of the immune system that can look like ITP. If the bone marrow looks normal, with the usual or higher number of cells that make platelets (megakaryocytes), and other blood tests are normal, then the doctor will diagnose persistent ITP.
How is ITP treated?
Most teenagers and adolescents do not need any treatment unless they have severe bleeding, and most teenagers and adolescents improve whether or not treatment is given. The type of treatment recommended depends on your symptoms rather than your platelet count. Most treatments aim to temporarily improve the platelet count and do not cure the condition itself. When treatments are considered, you will have the chance to discuss the risks and benefits of these, as opposed to no treatment, with the doctor. The options for treating ITP include:
1) No treatment
The majority of teenagers and adolescents with ITP have a low platelet count but do not have dangerous bleeding. Without treatment most teenagers and adolescents will have a platelet count over 20 within 5 days and a normal platelet count by six months.
2) Tranexamic acid
Tranexamic acid does not increase the platelet count but does help the blood to produce clots. It is particularly useful for gum bleeds, nose bleeds or heavy periods and helps the blood to form clots without altering the platelet count. It is best taken as a liquid ("swish and swallow") three times per day. It must not be used if there is any blood in the urine.
3) Hormonal treatment
Norethisterone is a drug used to stop girls' periods. This is done if their periods are extremely heavy.
Oral contraceptive pill – teenage girls with ITP can be put on the oral contraceptive pill to try and reduce heavy periods.
4) Steroid treatment
Steroids are sometimes given to teenagers and adolescents with ITP on a short-term basis in an attempt to increase their platelet count. However, when the steroid dose is reduced, the platelet count will drop again after a few days. Steroids should only be given for a short period of between 4 to 7 days.
Side effects such as weight gain and mood changes are common. Some teenagers and adolescents become very worried about their mood changes when they’re on steroids, so it is important to know that this is a perfectly normal side effect of the drug, as is increased appetite and disturbed sleep patterns.
Steroids can also affect your skin; you may notice that you get more spots while you are on the tablets.
Longer courses of steroids are not recommended as this may dampen the immune system, weaken bones, cause diabetes or obesity and stunt growth.
5) Intravenous immunoglobulin
Immunoglobulins are antibodies which can reduce platelet destruction. They are a blood product produced from many donors and have a theoretical but very low risk of transmitting blood-borne infections. One course of treatment with immunoglobulin takes a full day as an in-patient in the hospital and the benefit will usually last about a month. Side effects such as fever and headaches are common.
6) ‘Curative’ treatments
In ITP the majority of platelets are destroyed in the spleen. Removing the spleen (splenectomy) is often effective in preventing early destruction of the platelets and allows the count to rise. In teenagers and adolescents however this is rarely necessary unless the ITP persists and the child has recurrent severe bleeds. It is successful in about 3-4 out of 5 people. Splenectomy is a major surgical procedure and carries a long term risk of severe infection and blood clots. It is rarely performed as the risks of splenectomy usually outweigh the potential benefits. Alternative treatments such as rituximab or the newer TPO-mimetics are usually tried prior to considering splenectomy.
Rituximab kills the immune cells that clear the platelets out of the blood. By removing the cells that get rid of the platelets, the platelet count will increase. It is successful initially in about 2 in 3 people and can be curative in about one third. Side effects are common.
Eltrombopag and Nplate
These TPO-mimetic newer drugs increase the number of platelets that are made in the bone marrow without suppressing the immune system. They are currently not widely available for children or teenagers.
What about school, sport and holidays?
Most severe bleeds tend to occur in the first week it develops and in teenagers and adolescents with a platelet count under 20. In those teenagers and adolescents with a count over 20 they can return to school/college/university immediately after the head teacher/tutor has been informed about the ITP. In teenagers and adolescents with a lower platelet count school can resume after the first week and when the school has been informed. The ITP Support Association produces a leaflet for schools/colleges/universities and clubs (available free of charge to members).
If you are on steroids and haven’t had chicken pox then school will need to inform you if anyone in your class goes down with chicken pox.
As a general rule contact sports where there is a risk of head injury should only be undertaken with care with active ITP. When the platelet count is over 50 the only sports to avoid would be rugby, boxing and wrestling where serious injuries can occur. Below this level it is possible to undertake supervised training but taking precautions to wear the appropriate protective gear. These are only recommendations, and you should discuss with your doctor what you can and cannot do as everyone is different.
Common sense is important. You should take the proper precautions that each sport requires, for example you must wear a helmet if you go cycling and you should not run around the sides of a swimming pool, but everyone should be doing this anyway. Because you will bruise more easily than most people, it is a good idea if you wear knee and elbow pads during certain sports.
At school, you need to make sure your teachers are aware of your condition, and it is best if your parents do this with you.
It is best not to take any holidays abroad in the first three months of ITP as it may be difficult to get insurance. After this time most cases of ITP will have resolved. If the ITP does persist you will need to discuss further with your doctor and you may need specialist medical insurance. A list of recommended insurance companies is given in the ITP Support Association’s Holiday Guide (available free of charge to members)
What else can I do?
You should also avoid drugs like aspirin, ibuprofen or herbal medication which can increase the risk of bruising and bleeding. Finally, you should make sure that doctors and dentists and any other medical practitioner you see know that you have a low platelet count.
When to seek help?
When you’re sent home you will be given a clinic appointment for review at the hospital and an emergency number (usually the phone number to the hospital ward). You should tell your mum, dad or guardian if the following ever happen so they can contact the hospital:
- A nosebleed which will not stop after 30 minutes despite pinching the nose
- Prolonged gum bleeding
- Blood in the poo or urine
- Following a heavy blow to the head, particularly if you are stunned or sickly
- Persistent or severe headache
- Vomiting or drowsiness
- If you haven’t had chicken pox and someone you meet or at school has the virus
Is there a UK registry?
To maintain accurate numbers of cases of childhood ITP and investigate possible markers for risk of severe bleeding a UK registry has been established (www.uk-itp.org) Families may be routinely asked to consent for anonymous data to be stored on the registry.
The ITP Association has a booklet ITP ‘n’ Stuff specifically written for teenagers at school with ITP, available free of charge to members.