Synopsis
Diagnose immune platelet destruction by exclusion, grade bleeding rather than count alone, treat critical haemorrhage immediately, and choose observation, corticosteroid, immunoglobulin or durable second-line therapy collaboratively.
- ITP is an acquired immune thrombocytopenia caused by increased platelet destruction and impaired production, diagnosed after excluding alternative causes of an isolated low count.
- Confirm true thrombocytopenia with repeat count and film; platelet clumping, schistocytes, blasts, dysplasia and additional cytopenias argue for another pathway.
- Bleeding risk relates to count, but age, previous bleeding, anticoagulants, hypertension, falls, infection and procedure plans substantially modify it.
- Many adults with mild or no bleeding can be observed safely even at counts below the reference range; treatment aims for haemostasis, not normalisation.
- Short-course corticosteroid is a common initial treatment when clinically indicated; avoid prolonged unplanned prednisolone exposure because toxicity accumulates quickly.
- Intravenous immunoglobulin produces a faster temporary rise for significant bleeding, urgent procedure, pregnancy or need to avoid corticosteroid, but response is not durable.
- Test for HIV and hepatitis C and review medicines, alcohol, autoimmune disease, lymphoproliferative disease and pregnancy where clinically relevant.
- Platelet antibody tests have limited sensitivity and specificity and a negative result does not exclude ITP; routine marrow biopsy is unnecessary in a typical isolated presentation.
- Thrombopoietin-receptor agonists, fostamatinib, rituximab and splenectomy offer second-line strategies with different speed, durability, infection, thrombosis and monitoring profiles.
- ITP itself and some treatments increase thrombosis risk, so a low platelet count does not automatically protect against venous or arterial events.
Key red flags
Severe headache, vomiting, focal neurology, seizure or reduced consciousness with profound thrombocytopenia needs immediate imaging and rescue therapy.
Investigation priorities
Confirm isolated genuine thrombocytopenia and exclude fragments or blasts.
Management branches
True thrombocytopenia is found without immediate major bleeding.
- Review film, previous counts, medicines, alcohol, infection, vaccines, pregnancy, autoimmune symptoms, lymph nodes and spleen and assess bleeding systematically.
- Exclude pseudothrombocytopenia, TMA, DIC, liver disease, marrow failure, HIV, hepatitis C and drug or heparin causes from the phenotype.
- Name ITP only after the pattern is coherent and agree observation or treatment from bleeding, count, trajectory, comorbidity and patient priorities.
Key medicines
DexamethasoneA common adult initial regimen is 40 mg orally once daily for 4 days, sometimes repeated under haematology guidance; use a lower or alternative plan when toxicity risk dictates.Hyperglycaemia, insomnia, psychosis, hypertension, infection, gastrointestinal and bone effects require anticipatory management; response may relapse and prolonged unsupervised courses are avoided.
Intravenous immunoglobulinHaematology commonly uses 1 g/kg intravenously for one or two days, or an equivalent divided regimen, when a rapid temporary platelet rise is needed.Headache, aseptic meningitis, haemolysis, thrombosis, fluid load and renal injury occur; use ideal or adjusted weight and infusion precautions under local policy.