本文描述一位32歲女性病患，罹患全身性紅斑性狼瘡已有11年，規則於門診追蹤，因發燒、關節痛、胸痛，實驗室檢查發現貧血、血小板低下、補體（C3）低下、高效價之抗雙股去氧核糖核酸抗體（anti-dsDNA > 379 IU／mL）、尿液呈現蛋白尿，初步診斷懷疑全身性紅斑性狼瘡復發。靜脈注射高劑量methylprednisolone七天，血小板仍偏低，治療反應差。本個案實驗室檢查顯示溶血性貧血、血小板低下、週邊血液抹片顯示碎裂紅血球，確定微血管性溶血性貧血證據，且血液中ADAMTS 13嚴重缺乏其血中活性為0%，因此診斷為血栓性血小板低下紫斑症。緊急接受血漿置換術，同時持續高劑量類固醇與靜脈注射Rituximab治療，因而血小板上升、乳酸脫氫脢大幅下降、貧血改善，達到治療的成效。全身性紅斑性狼瘡同時出現血栓性血小板低下紫斑症，經緊急啟動血漿置換，會降低病人的死亡率。

A 32-year-old female patient in this study, who suffered from systemic lupus erythematosus (SLE) for 11 years. Upon a regular rheumatology outpatient follow-up, she presented not only with fever,arthralgia and chest pain, but also with anemia, low platelets, low complement (C3), and high titer anti-double-strand deoxyribonucleic acid antibody (anti-dsDNA > 379 IU/mL) on laboratory test report,as well as proteinuria on urinalysis. Accordingly, her condition was suspected to be a relapse of SLE. Unfortunately, after treatment with high-dose intravenous methylprednisolone, the response was poor with persistent low platelet level. Besides, hemolytic anemia and thrombocytopenia were noted and peripheral blood smear examination also showed fragmented red blood cells, supporting the diagnosis of microangiopathic hemolytic anemia. Moreover, there was severe ADAMTS13 deficiency in the blood, even with 0% of activity. Therefore, the patient was finally diagnosed with thrombotic thrombocytopenic purpura and then received urgent plasmapheresis in combination with high-dose glucocorticoid and of intravenous rituximab treatment. After the treatment, the platelet level increased, lactate dehydrogenase level remarkably decreased, and anemia gradually improved. Taken together, urgent initiation of plasma exchange together with glucocorticoid and rituximab treatment for SLE patient with thrombotic thrombocytopenic purpura could lower the mortality rate.