Haemolytic uraemic syndrome: report of a case and new pathogenetic concepts.

Haemolytic uraemic syndrome (HUS) is a severe clinical condition characterised by thrombocytopenia, microangiopathic haemolytic anaemia and renal impairment [1]. At histological examination hyaline microthrombi occluding terminal arterioles and capillaries are generally found. Other syndromes share major clinical and histological diagnostic criteria with HUS. In particular, there is no method at present which clearly differentiates HUS from thrombotic thrombocytopenic purpura (TTP) [2]. We propose therefore the term thrombotic microangiopathy (TMA) to discuss both syndromes. The pathogenesis of TMA is unclear and many forms of therapy have been attempted without definitive proof of efficacy. The recently reported [3] successful results with exchange transfusion and plasma infusion represented a consistent advance in the management of these diseases. The beneficial effect of these procedures was attributed to replacement of an unknown 'missing' factor in plasma. This finding generated recent observations possibly relevant in understanding the pathogenesis of these diseases.