Immune Thrombocytopenic Purpura

Question 1

Definition

Answer 1

Syndrome characterised by immune destruction of platelets resulting in bruising or a bleeding tendency

Question 2

Aetiology

Answer 2

• 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

Question 3

Associated with

Answer 3

o Infections (e.g. malaria, EBV, HIV)
o Autoimmune diseases (e.g. SLE, thyroid disease)
o Malignancies
o Drugs (e.g. quinine)

Question 4

Epidemiology

Answer 4

• Acute ITP presenting CHILDREN aged 2-7 yrs

• Chronic ITP is seen in ADULTS
o 4 x more common in WOMEN

Question 5

Presenting symptoms

Answer 5

• Easy bruising
• Mucosal bleeding
• Menorrhagia
• Epistaxis

Question 6

Signs on physical examination

Answer 6

• Visible petechiae and bruises

* Signs of other illness (e.g. infections, wasting, splenomegaly) would suggest that other causes

Question 7

Investigations (exclusions)

Answer 7

Diagnosis of exclusion - exclude:
o Myelodysplasia
o Acute leukaemia
o Marrow infiltration

Question 8

Investigations

Answer 8

• 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