Immune thrombocytopenia purpura

Question 1

Define ITP?

Answer 1

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

Question 2

what are the risk factors for ITP?

Answer 2

women of child bearing age

less than 10 or over 65 years old

Question 3

what may ITP be associated with?

Answer 3

Infections (e.g. malaria, EBV, HIV)

Autoimmune diseases (e.g. SLE, thyroid disease)

Malignancies

Drugs (e.g. quinine)

Question 4

outline the aetiology of ITP?

Answer 4

Often IDIOPATHIC

Acute ITP is often seen after viral infection in children

Chronic ITP is more common in adults

ITP may be associated with:

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

Autoantibodies are generated, which bind to platelet membrane proteins (e.g. GlpIIb/IIIa) resulting in thrombocytopaenia

Question 5

who is acute ITP often seen in?

Answer 5

after viral infection in children

Question 6

who is chronic ITP more common in?

Answer 6

adults

Question 7

summarise the epidemiology of ITP?

Answer 7

Acute ITP presenting CHILDREN

Chronic ITP is seen in ADULTS

4 x more common in WOMEN

Question 8

what are the presenting symptoms of ITP?

Answer 8

MEME

Mucosal bleeding

• e.g. bleeding gums

Easy bruising

Menorrhagia

Epistaxis

Absence of systemic symptoms (like weight loss, fever etc.), no splenomegaly/hepatomegaly/ lymphadenopathy

Question 9

What are the signs of ITP on physical examination?

Answer 9

Visible petechiae (can appear everywhere but most commonly found on lower limbs) and bruises

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

Question 10

what are the appopriate investigations for ITP?

Answer 10

FBC - low platelets (<100*10^9L) - ISOLATED LOW PLTS

Clotting screen - normal PT, APTT and fibrinogen

Autoantibodies (e.g. antiplatelet antibody)

Blood film- To rule out pseudothrombocytopaenia (which is caused by platelets clumping together and giving falsely low counts)​

Question 11

what investigations should you consider for ITP?

Answer 11

HIV/HepC serology: -ve

TFTs (as hyper-/hypothyroidism can cause thrombocytopenia)

Pregs test->ITP shoudl be avoided in pregnancy

Bone Marrow->To exclude other pathology