Post-renal Acute Kidney Injury Complicated by Urinary Tract Obstruction Due to Massive Blood Clots and Severe Thrombocytopenia in a Patient with Systemic Lupus Erythematosus: A Case Report.

Systemic lupus erythematosus (SLE) is often seen with antiphospholipid antibody syndrome (APS), and these conditions may occur concurrently with severe immune thrombocytopenia (ITP) and even acute kidney injury (AKI); however, post-renal AKI due to bleeding is uncommon. Here, we describe a case of post-renal AKI and anuria in a patient with SLE and APS, which were attributable to urinary tract obstruction due to massive blood clots caused by secondary ITP. A 50-year-old Japanese woman was admitted to our hospital with anuria, abdominal tenderness, purpura in the trunk and in both legs, and severe thrombocytopenia. She had been receiving medical treatment for APS and SLE till the age of 45 years. Computed tomography revealed a blood clot without extravasation in both urinary tracts, and she was diagnosed with post-renal AKI due to complete obstruction of the urinary system. Additionally, based on her medical history, elevated platelet-associated Immunoglobulin G (IgG) levels, and increased megakaryocyte count, she was diagnosed with secondary ITP complicated by SLE and APS. She also had elevated APS-related autoantibodies, including antiphosphatidylserine/prothrombin Immunoglobulin M (IgM), and IgG. However, concomitant serositis such as lupus enteritis or cystitis was not seen. She was treated with a combination of glucocorticoids, intravenous immunoglobulin, and continuous haemodialysis/haemofiltration, which resulted in rapid improvement of her symptoms and renal dysfunction. Secondary ITP-induced massive bleeding of urinary tract can cause post-renal AKI. Appropriate diagnosis and aggressive treatment are necessary to improve prognosis in such patients.