Thrombotic thrombocytopaenic purpura (TTP)

Last updated: Thursday, 20, January, 2011
PresentationAppropriate Tests

TTP is a rare disorder, caused by a congenital or aquired deficiency of the Von Willebrand factor (VWF) cleaning protease ADAMTS-13. There is a response to plasma exchange (in congenital disorders) and to plasmapheresis (in aquired disorders). There is a high mortality rate untreated. Its hallmarks are thrombocytopenia (often severe), red cell fragmentation and evidence of haemolysis, with variable CNS and renal dysfunction. Its treatment is a medical emergency.

FBC, blood film (red cell fragmentation), platelet count; creatinine, urea, electrolytes. Urine - urinalysis, microscopy. ADAMTS 13 assays are performed by some laboratories. Patients with phospholipid antibody syndrome may present with features resembling TTP.

See also Haemolytic uraemic syndrome

Microangiopathic haemolysis

Increased reticulocytes, bilirubin and LDH are expected with anaemia.


Variable but often severe.


Variable at presentation and may be absent. See also Pyrexia of unknown origin

Fluctuating neurological signs


Renal impairment, including