Idiopathic Thrombocytopenic Purpura

Question 1

What is idiopathic thrombocytopenic purpura (ITP)?

Answer 1

Idiopathic thrombocytopenic purpura (ITP) is a condition characterised by idiopathic (spontaneous) thrombocytopenia (low platelet count) causing a purpuric rash (non-blanching rash).

Question 2

Briefly describe the pathophysiology of ITP

Answer 2

ITP is caused by a type II hypersensitivity reaction. It is caused by the production of antibodies that target and destroy platelets. This can happen spontaneously, or it can be triggered by something, such as a viral infection.

Question 3

How does ITP present?

Answer 3

Idiopathic thrombocytopenic purpura usually present in children under 10 years old. Often there is a history of a recent viral illness. The onset of symptoms occurs over 24 – 48 hours:

• Bleeding
  
  • For example from the gums, epistaxis or menorrhagia
• Bruising
• Petechial or purpuric rash
  
  • Caused by bleeding under the skin

Question 4

Briefly differentiate between petechiae and purpura

Answer 4

Petechiae are pin-prick spots (around 1mm) of bleeding under the skin. Purpura are larger (3 – 10mm) spots of bleeding under the skin. When a large area of blood is collected (more than 10 mm), this is called ecchymoses. These are all non-blanching lesions.

Question 5

How is ITP confirmed?

Answer 5

The condition can be confirmed by doing an urgent full blood count for the platelet count. Other values on the FBC should be normal. Other causes of a low platelet count should be excluded, for example heparin induced thrombocytopenia and leukaemia.

Question 6

What does the severity of ITP depend on and thus treatment?

Answer 6

The severity and management depends on how low the platelet count falls. Usually no treatment is required and patients are monitored until the platelets return to normal. Around 70% of patients will remit spontaneously within 3 months.

Question 7

If patients need treatment for ITP, what is given?

Answer 7

Treatment may be required if the patient is actively bleeding or severe thrombocytopenia (platelets below 10):

• Prednisolone
• IV immunoglobulins
• Blood transfusions if required
• Platelet transfusions only work temporarily

Question 8

Why do platelet transfusions only work temporarily?

Answer 8

Platelet transfusions only work temporarily because the antibodies against platelets will begin destroying the transfused platelets as soon as they are infused.

Question 9

What advice should be given for ITP?

Answer 9

Some key education and advice is necessary:

• Avoid contact sports
• Avoid intramuscular injections and procedures such as lumbar punctures
• Avoid NSAIDs, aspirin and blood thinning medications
• Advice on managing nosebleeds
• Seek help after any injury that may cause internal bleeding, for example car accidents or head injuries

Question 10

What are the complications of ITP?

Answer 10

• Chronic ITP
• Anaemia
• Intracranial and subarachnoid haemorrhage
• Gastrointestinal bleeding