Reaction to Quinine

By Dr Michael P. Honan

The sudden onset of a petechial rash on the upper and lower extremities, ecchymosis of the tongue, and an episode of epistaxis prompted a 78-year-old woman to seek medical evaluation. She reported having taken one of her husband’s quinine( pills a day earlier to alleviate leg cramps. The patient was otherwise in good health and took no other medications. Her platelet count was 1000/µL (normal, 140,000 to 440,000/µL); a peripheral smear showed no platelet clumping. The absence of clumping and the patient’s presentation and history suggested drug-induced thrombocytopenia. The presence of platelet autoantibodies confirmed the suspicion of autoimmune-induced thrombocytopenia. Treatment with methylprednisolone( sodium succinate (125 mg every 6 hours) was initiated, and intravenous immune globulin was administered; the patient’s platelet count increased significantly. In this setting, if a patient’s condition does not improve with therapy, consider a bone marrow examination to rule out bone marrow infiltrative problems, lymphoma, and leukemia. In addition to quinine, numerous other drugs—such as quinidine(, the sulfonamides, and heparin(— have been implicated as a cause of thrombocytopenia.