[A man in his 50s with acute renal failure, anemia, and thrombocytopenia]

When haemolytic anaemia, thrombocytopenia and renal failure are present, a thrombotic microangiopathic (TMA) condition should be suspected. We describe the various differential diagnoses of primary TMA syndromes, their clinical findings, clinical workup and treatment.

A previously healthy man in his fifties was hospitalised with anaemia, thrombocytopenia, bilirubinaemia and acute renal failure. He was in good general condition without neurological symptoms. Due to suspicion of thrombotic microangiopathy (mainly thrombotic thrombocytopenic purpura (TTP)), he was referred to a university clinic for immediate plasma exchange. His renal failure deteriorated and haemodialysis was initiated. However, ADAMTS13 level was normal. Thus, complement-mediated thrombotic microangiopathy was suspected and eculizumab was administered. Due to previous abdominal discomfort a faecal sampling was performed, detecting enterohaemorrhagic E. coli (EHEC) DNA (Shigatoxin 2f). Hence, the diagnosis was Shigatoxin-induced haemolytic uraemic syndrome (ST-HUS). Supportive care was continued and renal function normalised.

When thrombotic microangiopathy is suspected, an assessment is made whether to initiate plasmapheresis and immunomodulatory treatment. A thorough workup is needed to differentiate between the various primary TMA syndromes. Thus, treatment with expensive and possibly harmful drugs can be avoided. The various primary TMA syndromes have overlapping clinical features, and the diagnosis can be difficult.