Summary

A 48-year-old lady who presented with sepsis secondary to a pelvi-ureteric junction obstruction was treated with an extended course of piperacillin/tazobactam. Four days after completing the course she developed thrombocytopaenia. Intravenous immunoglobulin was required to bring her platelet count back to normal. In the absence of other causes the authors believe that a delayed reaction to piperacillin/tazobactam was the cause of her thrombocytopaenia.