Idiopathic Thrombocytopenic Purpura

Question 1

What is the pathophysiology of idiopathic thrombocytopenic purpura?

Answer 1

Autoimmune disease in which antibodies attach to antigens on the surface of platelets platelets to be ingested by macrophages as they pass through the spleen.

Question 2

Which type of hypersensitivity reaction is idiopathic thrombocytopenic purpura?

Answer 2

Type 2 hypersensitivity reaction

Question 3

What is this a presentation of?

Preceding URTI/gastroenteritis, easy bruising and petechiae, spontaneous nosebleeds, prolonged bleeding after being cut.

Answer 3

Idiopathic thrombocytopenic purpura

Question 4

What are the main causes of low platelets in children?

Answer 4

1. Idiopathic/Thrombotic thrombocytopenic purpura
2. Disseminated intravascular coagulation
3. Haemolytic uremic syndrome
4. Malignancy, chemotherapy

Question 5

How is idiopathic thrombocytopenic purpura diagnosed?

Answer 5

Isolated thrombocytopenia and blood film to ensure there is no haemolysis.

Question 6

What is the management of idiopathic thrombocytopenic purpura?

Answer 6

1. Most do not require treatment and resolve spontaneously after three to six months.
2. Avoid contact sport and NSAIDs.
3. IV Ig rapidly increases platelet count if significant bleeding (platelet transfusions are unhelpful)

Question 7

What is the work up for purpura?

Answer 7

1. Is the child ill?
2. What is the platelet count?

Ill + low platelets - meningococcal septicaemia, DIC, HUS
Well + low platelets - ITP
Well + okay platelets - consider Henoch Schoenlein purpura