Thrombotic thrombocytopaenic purpura

What is TTP?

Thrombotic thrombocytopaenic purpura is a rare disorder of coagulation. It is due to a severe deficiency of ADAMTS13 activity, which leads to failure of cleavage of Von-Willebrand factor, resulting in platelet aggregation and thrombotic microangiopathy. Organs that can be affected include kidney (leading to kidney injury) and brain (leading to neurological symptoms). Untreated, TTP is life-threatening. 

If a patient presents with a suspected acute TMA, TTP should be excluded by detection of ADAMTS13 activity >10%. This can be done by taking a sample of citrated plasma PRIOR to the patient receiving plasma products.  Measurement of ADAMTS13 activity can be performed in the combined aHUS lab diagnostic services in Newcastle upon Tyne Hospitals. This can be done as part of an EMERGENCY REFERRAL to the National aHUS Service. Assays for ADAMTS13 activity are also available locally in some Trusts.

If there is strong suspicion of TTP,  plasma exchange should be strongly considered and an URGENT referral should be made to the regional TTP service in your area.

Thrombus formation in TTP

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Secondary TMA

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Diagnosis of aHUS

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Genetic Causes of aHUS

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