A Case of Thrombotic Microangiopathy (TMA) in a Patient with Systemic Lupus Erythematosus (SLE) and Acute Kidney Failure

Introduction: TMA refers to disorders characterized by endothelial injury, microvascular thrombosis, thrombocytopenia, and microangiopathic hemolytic anemia. TMA is unusual in SLE but may occur with antiphospholipid syndrome (APS). This is a case of a young male with a recent diagosis of ischemic basal ganglia stroke and thrombocyotpenia who returned to the hospital one month later with acute renal failure. Serological work-up revealed SLE with positive lupus anticoagulant and anti-cardiolipin Ab compatible for APS. Kidney biopsy revealed TMA with no lupus nephritis (LN). Case Description: 42 yo hispanic M with past medical history of hypothyroidism, hypertension, recently diagnosed ischemic stroke and thrombocytopenia presented to the ER complaining of poor appetite and weakness. Home meds included ASA, atorvastatin, losartan, nifedipine, and levothyroxine. Physical exam was remarkable for HR of 130 BPM, normotensive, dry mucous membranes and no volume overload. No history of toxic habits. Labs remarkable for Cr of 4.32 mg/dL, UA showed 2+ protein and >50 RBC's. CBC was normal except for plt of 55 103/uL. PBS negative for schistiocytes. Haptoglobin and ADAMS13 were normal. Remarkable serologies include anti-chromatin Ab, anti-dsDNA Ab, lupus anticoagulant, cardiolipin Ab, and low C4. Kidney biopsy revealed TMA (see figure 1). Patient completed 3 days of methylprenisolone with plans of 4 sessions of weekly rituximab along with prednisone and coumadin. Serum creatinine improved to 1.7 mg/dL after treatment. Discussion: TMA is more common in SLE patients with APS than in those without APS. APS can cause endothelial injury and thrombosis without immune complex deposition. This is consistent with our patient, who lacked features of primary TMAs. His biopsy ruled out LN and confirmed APS-TMA, highlighting an atypical renal manifestation of SLE.RBC fragmentation, endothelial cell swelling, and intracapillary fibrin thrombin