When should I consider referring a patient with suspected TTP to a specialist for further management?

When considering referring a patient with suspected thrombotic thrombocytopenic purpura (TTP), it is crucial to recognise that this is a serious condition requiring urgent specialist assessment and management, often initiated in emergency departments Pascual-Izquierdo et al. 2023.

Referral to a specialist, typically haematology, should be considered urgently based on platelet count and associated clinical features, as TTP is characterised by severe thrombocytopenia NICE CKS.

• Immediate referral or urgent specialist advice should be arranged for patients with a platelet count of less than 20 × 109/L, or with active bleeding, due to the significantly increased risk of spontaneous haemorrhage below this threshold NICE CKS.
• An urgent referral is indicated for patients with a platelet count of less than 50 × 109/L NICE CKS.
• For platelet counts within the range of 50–100 × 109/L, an urgent referral should be arranged if associated with:
  • Evidence of pancytopenia (haemoglobin less than 100 g/L, neutrophils less than 1 × 109/L) NICE CKS.
  • Splenomegaly or lymphadenopathy NICE CKS.
  • Pregnancy NICE CKS.
  • Upcoming surgical or interventional procedures NICE CKS.
• Patients with a platelet count of less than 100 × 109/L that is persistent and unexplained (on at least two occasions 4–6 weeks apart) should be referred to haematology NICE CKS.
• Additionally, any patient with a lowering platelet count trend, other haematological abnormalities, or who is generally unwell, should be referred NICE CKS.

For adults with a low platelet count and abnormal bruising where non-accidental injury is not suspected, referral to a haematologist for further investigations is also appropriate, with the urgency determined by clinical judgement NICE CKS. In pregnant women, close clinical observation is required as platelet counts may decrease before other clinical features of pre-eclampsia become apparent NICE CKS.