Haematology: Immune Thrombocytopenia Purpura

Question 1

ITP is the most common cause of thrombocytopenia in childhood. True or false?

Answer 1

True

Question 2

What is it caused by?

Answer 2

Destruction of circulating platelets by anti platelet IgG autoantibodies

Question 3

The reduced platelet count may be accompanied by what?

Answer 3

Compensatory increase of megakaryocytes in the bone marrow

Question 4

What age do most children present?

Answer 4

Between 2 and 10 years

Question 5

How does it typically present?

Answer 5

Onset 1/2 weeks after viral infection 
Petichiae
Purpura 
And/or superficial bruising 
Can cause epistaxis and other mucosal bleeding

Question 6

Is profuse bleeding uncommon?

Answer 6

Yes despite the fact that platelet count often falls below 10x10^9 /L

Question 7

What is a serious but rare complication?

Answer 7

Intracranial bleeding
Occurs in 0.1-0.5%
Mainly those with severe thrombocytopenia over a long period

Question 8

How is it diagnosed?

Answer 8

Diagnosis of exclusion

Attention to history, blood film and clinical features

Question 9

Any atypical features such as presence of anaemia, neutropenia, hepatosplenomegaly or marked lymphadenopathy should prompt what?

Answer 9

A bone marrow examination to exclude acute leukaemia or aplastic anaemia

Question 10

Why should a bone marrow examination be done if the child is going to be treated with steroids?

Answer 10

The treatment may mask to diagnosis of ALL

Question 11

What other condition should be considered?

Answer 11

SLE

Question 12

How is it managed?

Answer 12

In 80% = acute, benign and self limiting
It usually remits in 6-8 weeks
Most can be managed at home without treatment even if platelet less than 10x10^9
Give treatment if: evidence of major bleeding (GI/intracranial) or persistent minor bleeding e.g excessive epistaxis/menstrual
Options = Oral prednisolone, IV anti-D or IV immunoglobulin

Question 13

What are platelet transfusions reserved for?

Answer 13

Life threatening haemorrhage

They raise the platelet count only for a few hours

Question 14

What should the child avoid?

Answer 14

Trauma
Contact sports
While platelet count is very low

Question 15

What is defined as chronic ITP?

Answer 15

In 20% the platelet count remains low 6 months after diagnosis

Question 16

How is chronic ITP managed?

Answer 16

Majority = supportive treatment
Drug treatment offered if chronic persistent bleeding that affects daily activities or impairs QOL
Rituximab or thrombopoietic growth factors
Splenectomy reserved for children with failed drug therapy - increases infection risk

Question 17

What does those who have a splenectomy require?

Answer 17

Lifelong antibiotic prophylaxis

Question 18

When is a bone marrow examination not required?

Answer 18

If only the platelet count is low
Characteristic clinical features
No steroid treatment given