Clinical syndrome in which a decreased number of circulating platelets manifests as a bleeding tendency, causing petechiae, ecchymoses, purpura and bleeding from venepuncture sites, nose etc., in an otherwise healthy patient
Aetiology
May occur in isolation (primary ITP) or in association with other disorders (secondary)
Causes of secondary ITP include:
Other autoimmune disorders (including antiphospholipid antibody syndrome and systemic lupus erythematosus)
Viral infections (including cytomegalovirus, varicella-zoster, hepatitis C and HIV)
Infection with Helicobacter pylori
Medication
Lymphoproliferative disorders
Pathophysiology
Caused by a type II hypersensitivity reaction
It is caused by the production of antibodies that target and destroy platelets
This can happen spontaneously, or it can be triggered by something, such as a viral infection
Clinical presentation
Usually present in children under 10 years old
Often there is a history of a recent viral illness
The onset of symptoms occurs over 24-48 hours:
Bleeding, for example from the gums, epistaxis or menorrhagia
Bruising
Petechial or purpuric rash, caused by bleeding under the skin
Investigations
FBC - isolated thrombocytopenia
Management
Usually no treatment is required and patients are monitored until the platelets return to normal
Around 70% of patients will remit spontaneously within 3 months
Treatment may be required if the patient is actively bleeding or severe thrombocytopenia (platelets below 10):
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