Systemic lupus erythematosus (SLE) is a multisystemic inflammatory autoimmune disease caused by various autoantibodies and immune complexes. SLE and antiphospholipid antibodies are associated with thrombotic manifestations. However, renal artery thrombosis which causes renal artery occlusion is uncommon even in SLE patients with antiphospholipid antibodies. A 27-year-old woman with SLE suddenly developed left flank pain and generalized edema. From the laboratory workup, the woman was negative for antiphospholipid antibody and nephrotic- range proteinuria was detected. Computed tomography revealed renal artery thromboembolism and multiple renal infarctions with parenchymal perfusion defects in the left kidney. Renal biopsy showed WHO classification III and V lupus nephritis. Left flank pain, generalized edema and proteinuria were resolved and the thromboembolism resolved itself after a high dose of steroid and anticoagulation therapy. In SLE patients, sudden onset of unexplained flank pain is considered as a possible symptom of renal vessel thromboembolism even if the antiphospholipid antibody is negative.

Keywords: Systemic lupus erythematosus, Antiphospholipid antibodies, Renal infarction