Thrombotic thrombocytopaenic purpura
What is TTP?
Thrombotic thrombocytopaenic purpura is a rare disorder and characterised by microangiopathic anaemia, thrombocytopaenia and organ involvement. 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 microthrombi that result in the clinical manifestations. Organs that can be affected include the brain (leading to neurological symptoms) and the heart. Kidney involvement is minor rarely leading to dialysis requiring renal failure. Untreated, TTP is life-threatening.
Exclusion of TTP
If a patient presents with a suspected acute TMA, TTP should be excluded by detection of ADAMTS13 activity >10%. Until then, treatment with plasma exchange is strongly recommended. Measurement of ADAMTS13 activity can be performed in the combined aHUS lab diagnostic services in Newcastle upon Tyne Hospitals 7 days a week. This can be done as part of an EMERGENCY REFERRAL to the national aHUS service.