Idiopathic Thrombocytopaenic Purpura

What Is Idiopathic Thrombocytopaenic Purpura?

Idiopathic thrombocytopaenic purpura (ITP) is a bleeding disorder in which the blood does not clot as it should. The bleeding is due to a low number of platelets (PLATE-lets), blood cells that help the blood clot and stop bleeding. People with ITP often have purple bruises that appear on the skin. The bruises mean that bleeding has occurred in small blood vessels under the skin.

The words idiopathic, thrombocytopaenic, and purpura mean:

• Idiopathic (id-ee-o-PATH-ick) means that the cause of the disease or disorder is not known.
• Thrombocytopaenic (throm-bo-cy-toe-PEE-nick) means there is a lower-than-normal number of platelets in the blood.
• Purpura (PURR-purr-ah) are purple bruises where bleeding occurs just under the skin. Purple areas may also appear on the mucus membranes (for example, in the mouth). A person with ITP also may have bleeding that looks like tiny red or purple dots on the skin. These dots, often seen on the lower legs, are called petechiae (peh-TEE-kee-ay). Petechiae may look like a kind of rash.

With ITP:

• People may have nosebleeds, bleeding from the gums when they have dental work done, or other bleeding that is hard to stop.
• Women may have heavy menstrual bleeding.
• Symptomatic bleeding in the brain is very rare but can be life threatening if it occurs.

ITP is largely an autoimmune disease. The decrease in platelets occurs because the immune system attacks and destroys the body's own platelets, for an unknown reason. Normally, your immune system helps your body fight off infections and diseases. But when the immune system mistakenly attacks some part of a person's own body, this is called an autoimmune disease. Because "idiopathic" means "of unknown cause," a better name for most cases of ITP is immune thrombocytopaenic purpura.

What Are Platelets and How Do They Work?

Platelets are small blood cells, or thrombocytes (THROM-bo-sites), that are made in your bone marrow (along with other kinds of blood cells). Platelets circulate through the blood vessels and help stop bleeding by sticking together to seal small cuts or breaks in tiny blood vessels.

Types of ITP

There are two types of ITP: acute (temporary or short-term) ITP and chronic (long-lasting) ITP.

• Acute ITP generally lasts less than 6 months. It mainly occurs in children, both boys and girls, and is the most common type of ITP. It typically occurs following an infection caused by a virus. This type of ITP often goes away on its own within a few weeks or months and does not return. Treatment may not be needed.
• Chronic ITP is a long-lasting (6 months or longer) type of ITP that mostly affects adults. However, some teenagers and even younger children get this type of ITP. Chronic ITP affects women two to three times more often than men. Treatment depends on how severe the bleeding symptoms are and the platelet count. In mild cases, treatment may not be needed.

Other Names for Idiopathic Thrombocytopaenic Purpura

• Immune thrombocytopaenic purpura
• Autoimmune thrombocytopaenic purpura

What Causes Idiopathic Thrombocytopaenic Purpura?

In idiopathic thrombocytopaenic purpura (ITP), the immune system treats a person's own platelets as if they were invaders in the body, attacking and destroying them. The immune system attacks platelets by making proteins called antibodies. The antibodies bind to platelets (attach) and then are removed by the spleen (an organ that is part of the immune system and helps fight infection).

Normally, the immune system makes antibodies to fight off germs or other harmful things (called antigens) that enter the body. The reason why the immune system decides to attack platelets is not known.

Children who get the acute (temporary) type of ITP often have had a recent viral infection. It is possible that the infection somehow "triggers" or sets off the immune reaction that leads to ITP in these children. ITP in adults, on the other hand, does not seem to be linked to infections.

Who Is At Risk for Idiopathic Thrombocytopaenic Purpura?

• Both children and adults can develop idiopathic thrombocytopaenic purpura (ITP).
• Children usually get the acute (temporary) type of ITP. This type of ITP often follows an infection caused by a virus.
• Adults tend to get the chronic (long-lasting) type of ITP, rarely the acute type of ITP.
• Women are two to three times more likely than men to get chronic ITP.
• You cannot catch ITP from another person.

What Are the Signs and Symptoms of Idiopathic Thrombocytopaenic Purpura?

The signs and symptoms of idiopathic thrombocytopaenic purpura (ITP) are related to increased bleeding due to low numbers of platelets.

Signs include:

• Bruising (purpura): purplish areas on the skin or mucus membranes (such as in the mouth) due to bleeding. The bruises may occur for no apparent reason.
• Petechiae: pinpoint red spots on the skin (typically the legs) that often occur in groups and may look like a rash. The spots are due to bleeding under the skin.
• Bleeding that is hard to stop.
• Bleeding from gums (for example, when dental work is done).
• Nosebleeds.
• Heavy menstrual bleeding in women.
• Blood in the urine.
• Blood in the stool (bowel movement).

Symptomatic bleeding in the brain is very rare but can be life threatening if it occurs.

A low number of platelets causes no symptoms other than increased risk of bleeding. A low number of platelets is not responsible for pain, fatigue, difficulty with concentration, or any other symptoms.

How Is Idiopathic Thrombocytopaenic Purpura Diagnosed?

To diagnose idiopathic thrombocytopaenic purpura (ITP), doctors use your medical history, a physical exam, and blood tests.

Your medical history includes information about:

• Your signs and symptoms of bleeding
• Illnesses you have that could lower your platelet count or cause bleeding
• Medicines or any other supplements or remedies you take that could cause bleeding or lower your platelet count

Your doctor will do a physical exam and look for signs of bleeding and infection.

Your doctor will also order blood tests to measure the platelet count in your blood. These tests usually include:

• A complete blood count, to show the numbers of different kinds of blood cells, including platelets, in a small sample of your blood.
• A blood smear, which involves placing some of your blood on a slide. A microscope is then used to look at your platelets and other blood cells.

A blood smear is important to be sure that the platelet count is correct. In healthy people, the platelet count can be falsely low, since the chemical used in the tube during blood collection may cause platelet clumping.

If blood tests show that you have a low number of platelets, you may need additional tests to help with the diagnosis. For example, bone marrow tests may be used to see if enough platelets are being formed in the bone marrow.

In ITP, the red and white blood cell counts are normal.

A low platelet count can occur when the body destroys platelets or doesn't produce enough platelets, or both. In ITP, the platelet count is low because the body is destroying platelets faster than the bone marrow can make new ones.

Some people with mild ITP have few or no signs of bleeding. In that case, they might be diagnosed only after a blood test done for another reason shows that they have a low number of platelets (thrombocytopaenia). If other causes for low platelet count are ruled out, ITP may then be diagnosed.

How Is Idiopathic Thrombocytopaenic Purpura Treated?

Doctors decide whether to treat idiopathic thrombocytopaenic purpura (ITP) based on your bleeding symptoms and platelet count. When treatment is needed, medicines are often used, at least at first. Treatments used for children and for adults are similar.

ITP in Adults

Adults with ITP who have very low platelet counts or problems with bleeding are usually treated. Adults with milder cases of ITP may not need any treatment, other than monitoring their symptoms and platelet counts.

ITP in Children

The acute (temporary) type of ITP that occurs in children often goes away within a few weeks or months. Children with bleeding symptoms more than merely bruising (purpura) are usually treated. Milder cases in children may not need treatment other than monitoring and followup to be sure the platelet count returns to normal.

Medicines

If treatment is needed for adults or children with ITP, medicines are used first. Corticosteroids (cor-ti-co-STEER-roids) such as prednisone (PRED-ni-zone) are commonly used to treat ITP. These medicines, called steroids for short, help raise the platelet count in the blood by lowering the activity of the immune system. However, steroids have a number of side effects, and some people relapse (get worse) when treatment ends.

Some medicines used to help raise the platelet count are given intravenously (through a needle in a vein). These medicines include immune globulin and anti-(Rh) D immunoglobulin.

Other medicines may be tried if initial treatment doesn't help. These medicines are usually given after a splenectomy (splee-NECK-tuh-mee) has been performed.

Removal of the Spleen (Splenectomy)

If necessary, the spleen may be removed. This treatment is used mostly in adults whose ITP has not responded to steroids. Removing the spleen stops the destruction of platelets in the spleen, but it also may make the person more likely to get infections. It is important for a person without a spleen to watch for signs of infection, such as fever, and to get treatment right away.

Other Treatments

• Platelet transfusions. Some people with ITP who have severe bleeding may need to have platelet transfusions and be hospitalized. Although the lifespan of transfused platelets is shortened greatly by antiplatelet antibodies, platelets may be transfused before a surgery.
• Treating infections. If a person with ITP has an infection that can lower the number of platelets, treating the infection may help raise the platelet count and reduce bleeding problems.
• Stopping medicines. If an ITP patient is taking medicine that can lower the number of platelets or cause bleeding, stopping the medicine can sometimes help raise the platelet count or prevent bleeding. For example, aspirin and ibuprofen (EYE-boo-pro-fen) are common medicines that reduce platelet function. These medicines should not be used by persons with ITP.

Living With Idiopathic Thrombocytopaenic Purpura

If you have idiopathic thrombocytopaenic purpura (ITP):

• Avoid medicines such as aspirin or ibuprofen that can affect platelet function and increase your risk for bleeding.
• Avoid injury that can cause bruising and bleeding. If your child has ITP, it is important to protect him or her from injuries, especially head injuries that could cause bleeding in the brain. Ask your child's doctor about the need to restrict the child's activities.
• Find a doctor who is familiar with treating ITP patients. Haematologists are doctors who specialize in diagnosing and treating blood diseases and disorders.
• If you have had your spleen removed, you may be more likely to get infections. Watch for signs of infection, such as fever, and get treatment promptly.

ITP in Pregnancy

Pregnant women with ITP have healthy babies. However, some babies born to mothers with ITP are born with or develop low numbers of platelets soon after birth. Their platelets will return to normal without any treatment. Treatment can speed the recovery in the few babies whose platelet counts are very low.

The treatment of ITP in pregnancy depends on the platelet count. If treatment is needed, the doctor will take into consideration the treatment's possible effects on the unborn baby.

Women with milder cases of ITP can usually go through pregnancy without treatment. Pregnant women with a very low platelet count or a lot of bleeding are more likely to have serious heavy bleeding (haemorrhage) during delivery or afterward. To prevent haemorrhage, these women are usually treated.

Key Points

• Idiopathic thrombocytopaenic purpura (ITP) is a bleeding disorder that can lead to bruising and bleeding that are hard to stop.
• In people with ITP, the blood does not clot as it should.
• ITP is caused by a low number of platelets in the blood. Platelets help blood clot and stop bleeding.
• The low number of platelets in ITP occurs when the body's immune system attacks and destroys platelets. The reason for this is not known.
• People with ITP may have signs of bleeding, such as bruises (purpura) that appear for no reason or tiny red dots (petechiae) that are visible on the skin.
• Bleeding in ITP can also occur in the form of nosebleeds, bleeding gums, heavy menstrual bleeding, blood in the urine, or blood in the stool. The most dangerous bleeding from ITP is in the brain, but this is very rare.
• ITP can affect children and adults of all ages. More women than men get ITP.
• There are two types of ITP: acute ITP, which mostly affects children but does occasionally affect adults, and chronic ITP, which mostly affects adults but does occasionally affect children.
• In children, the illness is usually temporary (acute ITP) and often occurs following an infection caused by a virus. Most children get well quickly without any treatment.
• Adults with ITP have the long-lasting (chronic) form of ITP, but symptoms can vary a great deal, and some with mild ITP do not need treatment.
• ITP is not the only cause of low platelet count (thrombocytopaenia), so diagnosis includes ruling out other possible causes of a low number of platelets.
• Treatment depends on the type and severity of the illness. Those who have more severe symptoms are usually treated at first with medicines such as steroids.
• The spleen is sometimes removed if treatment with medicine fails to keep the platelet level high enough to prevent bleeding.