COVID-19 often contributes to thrombus formation in microvessels, resulting in damaged vital organs. In this study, we report a case of COVID-19 associated with acquired thrombotic thrombocytopenic purpura (TTP). A 44-year-old man with a history of systemic lupus erythematosus presented with COVID-19 and concomitant hemolytic anemia and a marked thrombocytopenia. The patient was diagnosed with acquired TTP because ADAMTS13 inhibitor was detected and ADAMTS13 activity below the sensitivity level. The patient developed agitated neuropsychiatric symptoms, such as aphasia, disorientation, and delirium, which improved after a plasma exchange, prednisolone, and rituximab administration. Only a few reports have revealed COVID-19 with TTP, and this is the first case in Japan. Although acquired TTP rarely develops, it is an important complication of COVID-19, and thus, it should be promptly diagnosed and treated as soon as possible.
