[Thrombotic thrombocytopenic purpura: a case report].

We report a case of thrombotic thrombocytopenic purpura (TTP) in a 60 years-old woman with Sjogren's syndrome. Symptomatology on admission leads to evoke the diagnosis of TTP. Biological results allow to set the diagnosis. Actually, association of haemolytic anaemia, schizocytes and thrombocytopenia are in favour of TTP. Undetectable ADAMTS 13 activity (below 5%) confirms the diagnosis. In congenital TTP, plasma ADAMTS 13 is absent or severely reduced as a consequence of mutations in the two ADAMTS 13 gene. In acquired TTP, circulating antibodies inhibit plasma ADAMTS 13 activity. In those cases, further biological studies are needed to find a cause of TTP. Follow-up implies standard laboratory tests. Plasma exchanges are progressively tapered after normalization of platelets count.