Idiopathic Thrombocytopenia Purpura

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IDIOPATHIC THROMBOCYTOPENIA PURPURA (ITP)

Definition: Isolated thrombocytopenia with otherwise normal blood count in a patient with no clinically apparent alte;rnate cause thrombocytopenia.

Epidemiology

Children: 2-5 years old (male = female)

Adults: 20-50 years old (female > male , 3:1)

40% of diagnoses are children <10 years of age

Spontaneous remission :

>80% in children

>20% in adult

Pathogenesis

¾ Caused by antiplatelet antibodies leading to phagocytic destruction.

¾ Increase platelet destruction, likely due to autoantibodies to platelet membrane antigens

¾ In children, ITP is acute, self-limiting disorder that resolves spontaneously.

¾ Abnormal autoantibody (Immunoglobulin G) binds to the platelet membrane, causing removal by the spleen. Although ITP mostly asymptomatic, if it left untreated it could lead to bleeding and possibly death.

Clinical manifestation

Acute: Preceding viral infection; resolves spontaneously within 3 months (90% of paediatrics) Most common viruses assoc. with ITP is Epstein-Barr Virus. In some patients ITP appear to arise in children affected with H.pylori or rarely following measles, mumps, rubella vaccine.

Chronic: Insidious onset of easy bruising/minor bleeding over few months, no antecedent infections, and duration >6 months (Adult)

Intracranial haemorrhage is the most frequent cause of death, occurring in 1-2% of patient diagnosed.

Spontaneous bleeding: Platelet count < 20,000/mm³(20x10⁹/L)

Bruising, Petachiae, Gingival bleeding. There is no splenomegaly.