PE26.6 | Idiopathic Thrombocytopenic Purpura — Summary & Reflection

KEY TAKEAWAYS

ITP in children — key points:

• ITP is the commonest cause of isolated thrombocytopenia in a previously well child, usually following a viral illness 2–4 weeks earlier.
• The hallmark CBC finding is isolated thrombocytopenia — normal Hb and WBC; any abnormality in other lineages mandates bone marrow examination to exclude leukaemia.
• Absence of hepatosplenomegaly is critical — organomegaly in a thrombocytopenic child raises the possibility of ALL.
• Pathophysiology: anti-GPIIb/IIIa IgG antibodies → splenic Fc-receptor-mediated platelet phagocytosis + impaired megakaryopoiesis.
• Management is severity-stratified: observation (mild, no significant bleeding), IVIG/anti-D/corticosteroids (moderate), IVIG + high-dose steroids ± platelet transfusion for severe/life-threatening.
• Never start steroids in an atypical case without first performing a bone marrow biopsy — steroids can transiently mask acute leukaemia.
• Anti-D immunoglobulin: Rh-positive, non-splenectomised patients only.
• Most childhood ITP resolves spontaneously within 6–12 months.

REFLECT

Reflect on today's learning using the Kolb cycle:

Concrete Experience: Think back to the opening case — a well child with sudden-onset petechiae, a very low platelet count, and a history of a viral illness. How did the normal WBC and Hb guide your thinking?

Reflective Observation: What would change in your approach if that same child had a palpable liver and spleen, or if the WBC showed a leucocytosis? How does the clinical picture shift the differential and the urgency of investigation?

Abstract Conceptualisation: The principle of 'diagnosis of exclusion' is central to ITP. What is the minimum dataset you need to confidently exclude leukaemia, aplastic anaemia, and TTP at the bedside before committing to an ITP diagnosis?

Active Experimentation: Next time you see a child in the OPD or emergency department with bruising or petechiae, practise performing and documenting a systematic examination — lymph nodes, liver, spleen, pallor — and interpreting a CBC with a differential diagnosis in mind.