Abstract
RATIONALE: Thrombotic thrombocytopenic purpura (TTP) is a severe and rare disease, and its complexity increases in the presence of underlying autoimmune disease and COVID-19 infection, making differential diagnosis and treatment more challenging. PATIENTS CONCERNS: A 43-year-old patient presented with high fever, intermittent cough, and tea-colored urine. DIAGNOSES: The patient had a long-term history of systemic lupus erythematosus (SLE) and lupus nephritis (LN). The nasopharyngeal swab confirmed the diagnosis of COVID-19 by RT-PCR, and plasma ADAMTS-13 activity was completely deficient (0%). It was considered that COVID-19 infection occurred on the basis of SLE disease and was then complicated with TTP. INTERVENTIONS: The patient was successfully treated with plasma exchange, followed by a combination of biologics and immunosuppressants. OUTCOMES: After 1 year of follow-up, the patient had completely recovered from COVID-19 infection and TTP, meeting the cure criterion. In addition, the LN was in remission, with an SLEDAI-2K score of 0, indicating a low disease activity state. LESSONS: This article indicates that the patient suffers from both long-standing underlying diseases and the sudden occurrence of SARS-CoV-2 infection, which complicates the determination of the etiology and diagnosis of TTP. Consequently, after thorough analysis of the disease progression, clinical manifestations, laboratory results, and treatment outcomes, it was primarily concluded that COVID-19 was the catalyst for the onset of TTP in this patient.