Immune Thrombocytopenic Purpura Defined

Idiopathic thrombocytopenic purpura (ITP) is a bleeding condition in which the blood doesn’t clot as it should. This is due to a low number of blood cell fragments called platelets (PLATE-lets).

Platelets also are called thrombocytes (THROM-bo-sites). They’re made in your bone marrow along with other kinds of blood cells. Platelets stick together (clot) to seal small cuts or breaks on blood vessel walls and stop bleeding.

You can understand the name of this disease by an explanation of its three parts. “Idiopathic” (id-ee-o-PATH-ick) means that the cause of the condition isn’t known.

“Thrombocytopenic” (throm-bo-cy-toe-PEE-nick) means there’s a lower than normal number of platelets in the blood. “Purpura” (PURR-purr-ah) refers to purple bruises caused by bleeding under the skin.

Symptoms and signs

The clinical picture ranges from no symptoms whatsoever to life-threatening intracranial haemorrhage. Some children with ITP will have no symptoms at all.

The most common presentation is petechiae or bruising. Up to a quarter present with nosebleeds. Haematuria and gastrointestinal bleeds are less common. Older girls may have menorrhagia.

Intracranial bleeds occur very rarely. In one large international study only 2.9% had severe bleeding at presentation, and there was only one case of intracranial bleed.

An initial impression of the severity of ITP is formed by examining the skin and mucous membranes, as follows:

Widespread petechiae and ecchymoses, oozing from a venipuncture site, gingival bleeding, and hemorrhagic bullae indicate that the patient is at risk for a serious bleeding complication

If the patient’s blood pressure was taken recently, petechiae may be observed under and distal to the area where the cuff was placed and inflated

Suction-type electrocardiograph (ECG) leads may induce petechiae

Petechiae over the ankles in ambulatory patients or on the back in bedridden ones suggest mild thrombocytopenia and a relatively low risk for a serious bleeding complication
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indings suggestive of intracranial hemorrhage include the following:

  • Headache, blurred vision, somnolence, or loss of consciousness
  • Hypertension and bradycardia, which may be signs of increased intracranial pressure
  • On neurologic examination, any asymmetrical finding of recent onset
  • On fundoscopic examination, blurring of the optic disc margins or retinal hemorrhage

What Are The Types of Idiopathic Thrombocytopenic Purpura (ITP)?

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

  • 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. Acute ITP often occurs after an infection caused by a virus.
  • Chronic ITP is long-lasting (6 months or longer) and mostly affects adults. However, some teenagers and children can get this type of ITP. Chronic ITP affects women 2 to 3 times more often than men.

What Are The Risk Factors for Idiopathic Thrombocytopenic Purpura (ITP)?

Both children and adults can develop idiopathic thrombocytopenic purpura (ITP).

Children usually get the acute (short-term) type of ITP. Acute ITP often develops after an infection caused by a virus. Adults tend to get the chronic (long-lasting) type of ITP. Women are 2 to 3 times more likely than men to get chronic ITP.

ITP is a fairly common blood disorder, with 50 to 150 new cases per every 1 million people each year; about half of these cases are children. However, the number of cases of ITP is rising because routine blood tests that can detect a low platelet count are being done more often.

ITP can’t be passed from one person to another.

Diagnosis

On complete blood cell count, isolated thrombocytopenia is the hallmark of ITP. Anemia and/or neutropenia may indicate other diseases. Findings on peripheral blood smear are as follows:

  • The morphology of red blood cells (RBCs) and leukocytes is normal
  • The morphology of platelets is typically normal, with varying numbers of large platelets
  • If most of the platelets are large, approximating the diameter of red blood cells, or if they lack granules or have an abnormal color, consider an inherited platelet disorder
  • Many children with acute ITP have an increased number of normal or atypical lymphocytes on the peripheral smear, reflecting a recent viral illness.

Clumps of platelets on a peripheral smear prepared from ethylenediaminetetraacetic acid (EDTA)–anticoagulated blood are evidence of pseudothrombocytopenia.

This diagnosis is established if the platelet count is normal when repeated on a sample from heparin-anticoagulated or citrate-anticoagulated blood.

Aspects of bone marrow aspiration and biopsy are as follows:

  • The value of bone marrow evaluation for a diagnosis of ITP is unresolved
  • Biopsy in patients with ITP shows a normal-to-increased number of megakaryocytes in the absence of other significant abnormalities
  • In children, bone marrow examination is not required except in patients with atypical hematologic findings, such as immature cells on the peripheral smear or persistent neutropenia.
  • In adults older than 60 years, biopsy is used to exclude myelodysplastic syndrome or leukemia
  • In adults whose treatment includes corticosteroids, a baseline pretreatment biopsy may prove useful for future reference, as corticosteroids can change marrow morphology
  • Biopsy is performed before splenectomy to evaluate for possible hypoplasia or fibrosis
  • Unresponsiveness to standard treatment after 6 months is an indication for bone marrow aspiration

Management

Treatment is considered on the basis of clinical symptoms and not on the basis of platelet count alone, as children with severe thrombocytopenia are often asymptomatic and do not have a serious risk of a bleed.

Outcomes other than platelet count are important in children with ITP, most especially the severity of haemorrhage, cost and side-effects of treatment, and overall quality of life.

No study has shown that any one treatment decreases mortality or alters the risk of ITP becoming chronic.

Treatment is based on the individual, taking into account factors such as platelet count, age, clinical picture, duration, lifestyle issues, cost, and concerns of all involved.

Prognosis

75-80% of children have completely recovered within six months and will go on to have no further problems.

A small number will develop a chronic thrombocytopenia, but most of these will require no treatment.

Adolescents (over the age of 10 years) may be more likely to develop persistent or chronic ITP.

Well under 1% develop intracranial haemorrhage.

Source & More Info: Medicine Net, E Medicine and Patient.co.uk

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