Immune Thrombocytopenic Purpura Flashcards
Definition
Syndrome characterised by immune destruction of platelets resulting in bruising or a bleeding tendency
Aetiology
- Often IDIOPATHIC
- Acute ITP is often seen after viral infection in children
- Chronic ITP is more common in adults
• Autoantibodies are generated, which bind to platelet membrane proteins (e.g. GlpIIb/IIIa) resulting in thrombocytopaenia
Associated with
o Infections (e.g. malaria, EBV, HIV)
o Autoimmune diseases (e.g. SLE, thyroid disease)
o Malignancies
o Drugs (e.g. quinine)
Epidemiology
• Acute ITP presenting CHILDREN aged 2-7 yrs
• Chronic ITP is seen in ADULTS
o 4 x more common in WOMEN
Presenting symptoms
- Easy bruising
- Mucosal bleeding
- Menorrhagia
- Epistaxis
Signs on physical examination
- Visible petechiae and bruises
* Signs of other illness (e.g. infections, wasting, splenomegaly) would suggest that other causes
Investigations (exclusions)
Diagnosis of exclusion - exclude:
o Myelodysplasia
o Acute leukaemia
o Marrow infiltration
Investigations
• Bloods
o FBC - low platelets
o Clotting screen - normal PT, APTT and fibrinogen
o Autoantibodies (e.g. antiplatelet antibody)
• Blood Film
o To rule out pseudothrombocytopaenia (which is caused by platelets clumping together and giving falsely low counts)
• Bone Marrow
o To exclude other pathology