What is ITP?
Idiopathic thrombocytopenia purpura (ITP) is an acquired disorder, resulting from an increase in the breakdown of platelets. ITP is not a cancer or malignancy. Platelets are small blood cells needed for normal blood clotting. In healthy people, old platelets are destroyed in the spleen by a type of white cell called a macrophage. With ITP, this process is much more rapid. Acute ITP occurs more frequently in children between the ages of two and nine, although it can occur in children of any age. ITP is found equally in boys and girls.
How platelets work
Platelets, or thrombocytes, are blood cells produced in the bone marrow. Platelets circulate in the blood for approximately eight to 10 days. At any given time, about two-thirds of all platelets are present in the blood stream while one-third remain in the spleen. New platelets are always being made in the bone marrow.
The main function of platelets is to prevent bleeding. A normal platelet count ranges from 150,000 to 400,000 per microlitre of blood. A microlitre is a unit of volume equal to one-millionth of a litre.
If your child has a low platelet count, they may bruise easily and bleed from superficial surfaces. For example, they may get nosebleeds. If your child's platelet count is less than 50,000 per microlitre, they will bruise more easily than normal. If your child's platelet count is less than 20,000 per microlitre, they may develop spontaneous bleeding.
Signs and symptoms of ITP
The most common sign of ITP is the appearance of numerous pinpoint haemorrhages, or petechiae, which look like tiny red spots under the skin. The presence of petechiae along with bruising is referred to as purpura. Both are caused by spontaneous bleeding in the skin and mucous membranes (surfaces in the skin and mouth). Except for signs of bleeding, your child may appear well.
Causes of ITP
The onset of ITP is generally sudden. Most cases occur a few days or even weeks after a viral infection, such as chicken pox or a respiratory infection. Sometimes ITP can be caused by an unusual response in the body to a drug. Researchers think that antibodies formed naturally by the body's immune system attach themselves to the platelets. The platelets are then rapidly destroyed. If the body is unable to produce enough new platelets to replace those destroyed by the antibodies, the number of platelets in the blood will decrease.
Diagnosing ITP
The doctor will take a careful history of your child's past health and current illness. If your child's doctor suspects ITP, a physical examination will be performed and a blood test will be ordered. Blood will be taken either by a finger prick or from a vein in the arm. The results of the physical examination and blood test will help confirm the diagnosis of ITP. In most cases, a sample of bone marrow will also be taken to rule out other causes of a low platelet count.
Once ITP has been diagnosed, a daily blood test is usually ordered to assess the number of platelets in the blood.
Treatment of ITP
ITP can be treated in several ways. Your child's doctor will advise you on whether treatment is necessary. Treatment is the same for both acute and chronic ITP. The following treatments are most common:
Prednisone
Prednisone is a steroid. It is given in pill form and taken by mouth.
Intravenous immunoglobulin
This is a protein solution prepared from the plasma of many blood donors. This solution is given by infusion into a vein over several hours. It works by temporarily preventing platelet destruction in the spleen. The spleen is the body organ responsible for the rapid destruction of the platelets.
Intravenous Anti-D
Like intravenous immunoglobulin, Anti-D is a protein solution prepared from blood plasma. The solution is given by infusion into a vein over a 20- to 30-minute period. It also works by temporarily preventing platelet destruction in the spleen.
Splenectomy
If ITP does not respond to medical treatment, or the side effects of the treatment are too severe, a splenectomy may be required. A splenectomy is the removal of the spleen by a surgical procedure.
Following treatment, the platelet count should rise. The petechiae and bruising will begin to disappear. Your child's doctor will probably want a few blood tests done, at regular intervals, to assess the platelet counts.
Medical treatment does not actually cure ITP. Instead, it raises the platelet count for a period ranging anywhere from a few weeks to even months. If your child's ITP does not clear up spontaneously during this time, the platelet count will fall again. More therapy will be required until the ITP disappears spontaneously.
Side effects of medication
Prednisone
The most common side effect is weight gain due to increased appetite. It is characterized by a "moon face," "pot belly" and fat deposits on the back of the shoulders. These symptoms are temporary and will disappear when the drug is stopped.
Other side effects associated with prednisone include:
- acne
- increased blood pressure
- a change in the level of blood sugar
- mood swings ranging from euphoria to temper tantrums
If your child is taking prednisone and comes into contact with chicken pox, seek medical attention right away. Your child's doctor may want to change the type of treatment.
Intravenous immunoglobulin
The most common side effects are headaches, fever, and nausea. In most cases, these side effects occur when two treatments are given back-to-back (12 hours apart). Give your child acetaminophen to relieve their headache and/or fever. Similarly, give your child dimenhydrinate to treat nausea and vomiting. Within 24 hours after the second dose of intravenous immunoglobulin, the symptoms should disappear. If only a single dose of intravenous immunoglobulin is given, the chance of these side effects occurring is small.
Intravenous Anti-D
The most serious side effect is a drop in the level of haemoglobin (red cells) in the blood. The biggest drop will occur seven to 10 days after the Anti-D has been given. Your child may appear tired and pale. In most cases, the haemoglobin does not drop low enough to require a transfusion.
Medications to avoid
If your child has ITP, always check with their doctor before giving them any medication. Acetylsalicylic acid (ASA) or any medication that contains ASA should be avoided. This is because ASA interferes with platelet function for a period of seven to 10 days. If your child has a low platelet count, this may increase their risk of bleeding. All over-the-counter cough and cold medications should be carefully checked before being bought. If you are unsure if a medicine contains ASA or not, check with your pharmacist.
The following is a short list of medicines that should not be given to your child with ITP:
- ASA and all compounds that contain it
- antihistamines
- non-steroidal anti-inflammatory drugs (NSAIDs)
- vitamin E
- cod liver oil
ITP and physical activity
Your child's level of physical activity should be restricted until their platelet count surpasses 50,000 per microlitre. Speak to your child's doctor about these restrictions. Limiting physical activity will decrease the risk of bleeding from injury or trauma.
Contact sports like soccer, football and hockey should be avoided until your child's platelet count has reached 100,000 per microlitre. Swimming is allowed but diving is not. If your child rides a bicycle, make sure they always wear their helmet. A bump or blow to the head could result in bleeding into the brain. If your child does hit their head, seek medical attention right away.
Toddlers should be closely supervised to reduce their risk of falls and tumbles from chairs, tables and stairs.
ITP and dental care
Your child should continue to see their dentist. However, a platelet count is necessary before any invasive work is done. If their platelet count is too low (below 50,000 per microlitre), work such as cleaning, filling and tooth extractions should be avoided until the count rises to a safe level. Decisions regarding dental treatment should be made by your child's dentist and doctor.
ITP and immunizations
Your child should not receive their immunizations, especially those that contain live attenuated viruses. These include the measles, mumps, rubella (MMR) and oral polio vaccines. Also, intramuscular injections (injections into a muscle) should not be given. Once your child has recovered from ITP, they will then be able to receive any missed immunization.
Prognosis of ITP
In most children, ITP is a self-limiting disease. About 80% to 90% of patients recover spontaneously, usually within three months from the beginning of the illness. This is called acute ITP. In a small percentage of patients, the disease will persist for six months or longer. This is called chronic ITP. Recurrence of ITP is uncommon but may occur up to several years after the initial episode. This is sometimes associated with another viral infection.