Acquired thrombotic thrombocytopenic purpura: puzzles, curiosities and conundrums.

We report a case of acquired thrombotic thrombocytopenic purpura (TTP) in a 34-year old patient with a prior diagnosis of systemic lupus erythematosis (SLE) who was recently started on hydroxychloroquine. Presenting symptoms included fevers, sore throat and productive cough with progressive weakness, dyspnea on exertion, hemoptysis and dark urine. Initial laboratory abnormalities were consistent with an acute microangiopathic hemolytic anemia and severe thrombocytopenia. At the time of admission, the patient's lupus was highly active as evident by his high SLE Disease Activity Index (SLEDAI) score. He was later also found to have severely reduced ADAMTS-13 levels and a positive antibody assay. This case highlights the occasional difficulty in pinpointing the exact etiology of TTP as well as establishes a possible novel drug association between hydroxychloroquine and TTP development.