Description Medical Coagulation Disorders

I diopathic thrombocytopenia purpura (ITP) is an acquired hemorrhagic disorder that is characterized by an increased destruction of platelets because of antiplatelet antibodies. The antibodies attach to the platelets, reduce their life span, and lead to a platelet count below 100,000 mm3 but occasionally as low as 5000 mm3. ITP can be divided into two categories: acute and chronic. Acute ITP is generally a self-limiting childhood disorder, whereas chronic ITP predominantly affects adults and is characterized by thrombocytopenia of more than 6 months.

The most life-threatening complication of ITP is intracerebral hemorrhage, which is most likely to occur if the platelet count falls below 1000 mm3. Hemorrhage into the kidneys, abdominal cavity, or retroperitoneal space is also possible. Prognosis for acute ITP is excellent, with nearly 80% of patients recovering without treatment. The mortality rate from hemorrhage is 1% in children and 5% in adults. Older age and a previous history of hemorrhage increase the risk of severe bleeding in adults. Prognosis for chronic ITP is good, with remissions lasting weeks or even years.

Acute ITP is thought to be a response to a viral infection. Generally, a viral infection, such as rubella or chickenpox, occurs 2 to 21 days before the onset of the disease. Acute ITP may occur after live vaccine immunizations and is most prevalent during the winter and spring months when the incidence of infection is high. It is also associated with human immunodeficiency virus (HIV). Chronic ITP generally has no underlying viral association and is often linked to immuno-logic disorders, such as lupus erythematosus, or to drug reactions.

While a clear genetic contribution has not been established, ITP has been seen in monozygotic twins, and a predisposition to autoantibody production can run in families.

Acute ITP affects children of both sexes between the ages of 2 and 9 years. Almost 50% of those children recover in 1 month, and 93% recover completely by 1 year. More than 80% of acute ITP patients recover, regardless of treatment, but 10% to 20% progress to chronic ITP. ITP can also occur during pregnancy, and 5% to 20% of the neonates born to these mothers will have severe thrombocytopenia and are at risk of intracranial hemorrhage during vaginal birth. Chronic ITP occurs mainly between the ages of 20 and 50 years and affects women almost three times as often as men. There are no known racial and ethnic considerations.

HISTORY. Ask if the patient has recently had rubella or chickenpox or a viral infection with symptoms such as upper respiratory or gastrointestinal (GI) symptoms. Ask if the patient was recently immunized with a live vaccine. Check for a history of systemic lupus erythematosus; easy bruising; or bleeding from the nose, gums, or GI or urinary tract. Because the symptoms of chronic ITP are usually insidious, patients may not have noticed an increase in symptoms. With

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