Idiopathic Thrombocytopenic Purpura

Question 1

Define Idiopathic Thrombocytopenic Purpura

Answer 1

Haematological disorder characterised by isolated thrombocytopenia (platelet <100 x 109/L) in the absence of an identifiable cause

Question 2

What are the causes and risk factors Idiopathic Thrombocytopenic Purpura

Answer 2

Thought to be the destruction of circulating platelets by IgG autoantibodies

Age <10yo
Women of childbearing age

Question 3

What is the epidemiology of Idiopathic Thrombocytopenic Purpura

Answer 3

Childhood ITP has an incidence of 1.9-6.4 in 100,000 per year with equal distribution between sexes
Most common cause of thrombocytopenia in childhood
More common in females (3:1) for young adults

Question 4

What are the symptoms of Idiopathic Thrombocytopenic Purpura

Answer 4

Mostly between 1-2yo and >10yo
Precipitated by viral infection of vaccination

Signs of bleeding
- Bruising (arms and legs, torso if severe)
- Petechiae (small red/purple spots, 1-5mm), mostly on the lower limbs
- Haemorrhagic bullae (2-5mm on mucosal surfaces of the oral cavity and tongue)
- Bleeding gums

NO systemic symptoms
NO causative medication Hx

Question 5

What are the differentials for Idiopathic Thrombocytopenic Purpura

Answer 5

Pseudothrombocytopenia (Agglutination when exposed to EDTA
Henoch-schonlein purpura
NAI
Coagulation factor deficiency
Acute leukaemia
Congenital/acquired thrombocytopenia
thrombotic thrombocytopenic purpura

Question 6

What are the signs of Idiopathic Thrombocytopenic Purpura on examination

Answer 6

General/skin
- Bruising (arms and legs, torso if severe)
- Petechiae (small red/purple spots, 1-5mm), mostly on the lower limbs
- Haemorrhagic bullae (2-5mm on mucosal surfaces of the oral cavity and tongue)

Head and neck: ?lymphadenopathy to exclude lymphoproliferative, autoimmune, or infectious aetiology

Abdominal: ?hepatosplenomegaly to rule out other differentials

Question 7

What investigations should be done for Idiopathic Thrombocytopenic Purpura

Answer 7

Diagnosis of exclusion

Bedside: H. Pylori breath test/stool antigen test
Bloods:
- FBC: Isolated platelet count <100 × 10⁹/L (<100 × 10³/microlitre), otherwise NORMAL
- Blood smear: distinguish between pseudo and ITP
- HIV/hepC serology
Other: bone marrow aspiration (if suspecting neoplastic/aplastic processes)

Question 8

What is the management for a first presentation of Idiopathic Thrombocytopenic Purpura

Answer 8

Minor bleeding: observe + avoid antiplatelets (aspirin, NSAIDs) + reduce trauma risk

Symptomatic/major bleeding: IVIg + corticosteroids ± platelet transfusion

Question 9

What is the long-term management for Idiopathic Thrombocytopenic Purpura

Answer 9

First line: Mycophenolate (after acute treatment as failed)
Second line: rituximab, thrombopoietin receptor agonists e.g. eltrombopag
Third line: splenectomy

Question 10

What are the complications of Idiopathic Thrombocytopenic Purpura

Answer 10

Intracranial haemorrhage
Persistent disease: ITP continues 3-6 months after diagnosis
Chronic disease: ITP continues >6 months after diagnosis

Question 11

What is the prognosis for Idiopathic Thrombocytopenic Purpura

Answer 11

Benign condition in children
Majority of children who are asymptomatic or have minor bleeding symptoms will attain normalisation of platelet count
30-70% of children recover within 3 weeks
Major bleeding is rare
Chronic ITP affects 20% of children with ITP

Question 12

What are the secondary causes of immune thrombocytopenic purpura

Answer 12

HIV
Hepatitis C
H. Pylori
Immunodeficiencies
Immunological/autoimmune disorders e.g. SLE, Evan’s syndrome, antiphospholipid syndrome, autoimmune thyroid disease
Lymphoproliferative disorders
Drug-induced
Vaccine exposure