Idiopathic Thrombocytopenic Purpura

1 What is Idiopathic Thrombocytopenic Purpura?

Immune thrombocytopenia (ITP) is an autoimmune disease involving platelets. In autoimmune disorders your body makes proteins called antibodies which damage another part of your body. In ITP the antibodies are made against platelets.

Once the antibodies have attached to platelets, the platelets do not work so well. They are also removed more quickly by the spleen because they are abnormal.

  • It used to be called "idiopathic thrombocytopenic purpura." Idiopathic means that there is no known underlying cause found. Nowadays the word "immune" has replaced the word "idiopathic" because it is known that the immune system is the cause.
  • Thrombocytopenia or thrombocytopenic means not enough platelets.
  • Purpura is a purple-red rash. It is caused by tiny bleeds under the skin.

2 Symptoms

Most children with idiopathic thrombocytopenic purpura will not have any symptoms.

  • Those who do develop symptoms have bruising or a purple or red rash - purpura. There may be tiny red spots, or larger areas of bruising or rash. This usually appears over 1-2 days.
  • Some have nosebleeds. Older girls may have heavier periods.
  • The condition often occurs about 2-3 weeks after an infection (often a common viral infection). Occasionally, it follows immunization. The symptoms often disappear over 6-8 weeks, and by 6 months in most cases.
  • Very occasionally, it causes severe bleeding which requires emergency treatment.
  • The platelet levels in about 1 or 2 in 10 affected children do not return to normal after a year. This is then called chronic ITP, which means it is persistent. However, many of these children will never need any treatment.

In adults, ITP comes on gradually and does not usually follow a viral illness. It is not really known what causes the disease. The symptoms may vary a lot.

You may have no symptoms, purpura, mild bruising or bleeding, or severe bleeding.

Unlike ITP in children, most adults with ITP will continue to have a low number of platelets indefinitely. This is called chronic ITP.

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3 Causes

In some people thrombocytopenia is caused by the immune system mistakenly attacking and destroying platelets. If the cause of this immune reaction is unknown, the condition is called idiopathic thrombocytopenic purpura. Idiopathic means "of unknown cause."

In most children with ITP, the disorder follows a viral illness, such as the mumps or the flu. It may be that the infection triggers the immune system malfunction.

4 Making a Diagnosis

Making a diagnosis of idiopathic thrombocytopenic purpura is done by performing several tests and procedures.

The physician will take a medical history and perform a thorough physical examination. A careful review of medications the patient is taking is important because some drugs can be associated with thrombocytopenia.

A complete blood count (CDC) will be done to quantifying the numbers for each type of blood cells including platelets. A low platelet count will establish thrombocytopenia as the cause of purpura.

Often the next procedure is a bone marrow examination to verify that there are adequate platelet-forming cells (megakaryocyte) in the marrow and to rule out other diseases such as metastatic cancer (cancer that has spread to the bone marrow) and leukemia (cancer of the blood cells themselves).

Another blood sample may be drawn to check for other conditions sometimes associated with thrombocytopenia such as lupus and infection.

Forms of ITP - Acute or Chronic, Primary or Secondary

Acute (temporary) thrombocytopenic purpura is most commonly seen in young children. Boys and girls are equally affected.

Symptoms often, but do not necessarily, follow a viral infection. About 85 percent of children recover within 1 year and the problem doesn't return.

Thrombocytopenic purpura is considered chronic when it has lasted more than 6 months. The onset of illness may be at any age.

Adults more often have the chronic disorder and females are affected two to three times more than males. The onset of illness may be at any age.

Primary ITP, also known as Idiopathic, is when ITP develops for no known reason.

Secondary ITP is associated with other illnesses such as an infection or autoimmune disease, or occur after transfusion or taking certain drugs, for instance cancer drugs.

5 Treatment

Treatments for idiopathic thrombocytopenic purpura include:

  • Oral corticosteroids
  • IV immune globulin (IVIG)
  • IV anti-D immune globulin
  • Splenectomy
  • Thrombopoietin receptor agonist drugs
  • Rituximab
  • Other immunosuppressants
  • For severe bleeding, IVIG, IV anti-D immune globulin, IV corticosteroids, and/or platelet transfusions

Adults with bleeding and a platelet count < 30,000/µL are usually given an oral corticosteroid (eg, prednisone 1 mg/kg po once/day) initially.

An alternative, but probably less effective, corticosteroid regimen is dexamethasone 40 mg po once/day for 4 days. If there is concurrent severe bleeding or a need to rapidly increase the platelet count, IVIG or IV anti-D immune globulin may be added to the corticosteroids.

Most patients respond with a rise in platelet count in 2 to 4 wk; however, when the corticosteroid is tapered after response, most adult patients relapse. Repeated corticosteroid treatments may be effective but increase the risk of adverse effects.

Corticosteroids should not usually be continued beyond the first several months; other drugs may be tried in an attempt to avoid splenectomy.

Splenectomy can achieve a complete remission in about two thirds of patients who relapse after initial corticosteroid therapy, but it is usually reserved for patients with severe thrombocytopenia, bleeding, or both. Splenectomy may not be appropriate for patients with mild disease.

If thrombocytopenia can be controlled with medical therapies, splenectomy is often deferred for 6 to 12 months to allow for the chance of spontaneous remission.

Splenectomy results in an increased risk of thrombosis and infection (particularly with encapsulated bacteria such as pneumococcus); patients require vaccination against Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis (ideally 2 wk before the procedure).

Second-line medical therapies are available for patients who are seeking to defer splenectomy in hope of a spontaneous remission, those who are not candidates for or refuse splenectomy, and those in whom splenectomy has not been effective.

Such patients usually have platelet counts < 10,000 to 20,000/μL (and thus are at risk for bleeding). Second-line medical therapies include thrombopoietin receptor agonists, rituximab, and other immunosuppressive agents.

Thrombopoietin receptor agonist drugs, such as romiplostim 1 to 10 mcg/kg sc once/wk andeltrombopag 25 to 75 mg po once/day, have response rates > 85%.

However, thrombopoietin receptor agonists need to be administered continuously to maintain the platelet count >50,000/μL. Rituximab (375 mg/m2 IV once/wk for 4 wk) has a response rate of 57%, but only 21% of adult patients remain in remission after 5 yr.

More intensive immunosuppression may be required with drugs such as cyclophosphamide and azathioprine in patients unresponsive to other drugs who have severe, symptomatic thrombocytopenia.

Treatment of children is usually supportive because most children spontaneously recover. Even after months or years of thrombocytopenia, most children have spontaneous remissions.

If mucosal bleeding occurs, corticosteroids or IVIG may be given. Corticosteroid and IVIG use is controversial because the increased platelet count may not improve clinical outcome.

Splenectomy is rarely done in children. However, if thrombocytopenia is severe and symptomatic for > 6 months, then splenectomy is a consideration.

In children or adults with ITP and life-threatening bleeding, rapid phagocytic blockade is attempted by giving IVIG 1 g/kg once/day for 1 to 2 days or a single dose of IV anti-D immune globulin 75 mcg/kg.

This treatment usually causes the platelet count to rise within 2 to 4 days, but the count remains high for only 2 to 4 wk.

High-dose methylprednisolone (1 g IV once/day for 3 days) is less expensive than IVIG or IV anti-D immune globulin and is easier to administer but may not be as effective. Patients with ITP and life-threatening bleeding are also given platelet transfusions.

Platelet transfusions are not used prophylactically.

Oral corticosteroids or IVIG or IV anti-D immune globulin may also be given when a transient increase of the platelet count is required for tooth extractions, childbirth, surgery, or other invasive procedures.

6 Prevention

Since the cause of idiopathic thrombocytopenic purpura is unknown, there are no specific ways of preventing it. However, bleeding and injury can be serious for people with ITP. To decrease the chance of bleeding injuries:

  • Take precautions in your child's environment. Consider padding an infant's crib or play area.
  • Make sure that older children wear helmets and protective gear when playing sports. This will help to reduce bruising injuries.
  • Consider temporarily stopping contact sports such as football and rough game playing when platelet counts are low.
  • Avoid medications that contain aspirin or ibuprofen. These medications can reduce platelet activity.

7 Lifestyle and Coping

Lifestyle modifications are necessary in order to cope with idiopathic thrombocytopenic purpura.

If you have ITP, try to avoid injuries, especially head injuries that can cause bleeding in the brain. For example, don’t participate in contact sports such as boxing, football, or karate. Other sports, such as skiing or horseback riding, also put you at risk for injuries that can cause bleeding.

Some safe activities are swimming, biking, and walking. Ask your doctor about physical activities that are safe for you. Take precautions such as regular use of seat belt and wearing gloves when working with knives and other tools.

If your child has ITP, ask his or her doctor whether you need to restrict your child's activities.

Ongoing Care:

Find a doctor, preferably a hematologist, who is familiar with treating people who have ITP. Hematologists are doctors who specialize in diagnosing and treating blood diseases and disorders. Discuss with your doctor how to manage ITP and when to seek medical care.

Talk to your doctor before taking prescription and over-the-counter medicines and nutritional supplements. Some medicines and supplements can affect platelets and increase your chance of bleeding. Common examples are aspirin or ibuprofen.

Tell your doctor about all of the over-the-counter medicines you take, including vitamins, supplements, and herbal remedies. These products may contain substances that increase your risk of bleeding.

Watch for symptoms of infection, such as a fever, and report them to your doctor promptly. If you've had your spleen removed, you may be more likely to become ill from certain types of infection.

Idiopathic Thrombocytopenic Purpura in Pregnancy:

In women who are pregnant and have ITP, the ITP usually doesn't affect the baby. However, some babies born to mothers who have ITP are born with or develop low numbers of platelets soon after birth.

Their platelet counts almost always return to normal without any treatment. Treatment can speed the recovery in the few babies whose platelet counts are very low.

Treatment for ITP during pregnancy depends on a woman's platelet count. If treatment is needed, the doctor will take a close look at the possible effects of the treatment on the unborn baby.

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

8 Risks and Complications

The most dangerous complication of idiopathic thrombocytopenic purpura (ITP) is bleeding, especially bleeding into the brain, which can be fatal. However, serious bleeding is rare.

The treatments for ITP can have more risks than the disease itself. The long-term use of corticosteroids can cause serious side effects, including:

Surgery to remove the spleen permanently increases your risk of infection and the risk of becoming ill if you get an infection. It’s important to watch for any symptoms of infection and report them to your doctor promptly.

Any fever, particularly when accompanied by signs or symptoms that suggest an illness more serious than the common cold, requires prompt medical attention and, possibly, early antibiotic treatment.

Children with a fever (temperature of 38.8 º C [102 º F] or higher) should receive IV antibiotics until bacterial infection is excluded.

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