There are so few true haematological emergencies that they are often way down the list as a differential diagnosis. Those that do exist, however, can prove devastatingly fatal if left untreated and a case is presented of one such possible diagnosis, thrombotic thrombocytopenic purpura, which falls into the remit of many possible presenting conditions. Particularly prevalent in young adults, this condition must always be thought of in any patient presenting with confusion, renal impairment, fever or other neurological abnormalities.