microangiopathies: diagnostic experience

is a rare disorder with an annual incidence of 3.7 cases per 106 individuals [2], possibly slightly increasing in recent years [3]. It is characterised by microvascular platelet clumping resulting in Background: Severe deficiency of von Wille-brand factor-cleaving protease (ADAMTS-13) ac-tivity (<5 % of normal) is specific for classical thrombotic thrombocytopenic purpura (TTP), a disorder presenting with thrombocytopenia, mi-croangiopathic haemolytic anaemia and often with organ dysfunction such as neurological symptoms, renal failure, and fever. A certain, though accord-ing to several case series, variable percentage of pa-tients with clinically diagnosed TTP and most pa-tients with other forms of thrombotic microan-giopathies (TMA) do not show severe ADAMTS-13 deficiency