Renal Riddles: Decoding a Case of Lupus Nephritis

Introduction: Systemic lupus erythematosus (SLE) is characterized by the production of autoantibodies resulting in immune-mediated injury often involving multiple organs. Current literature suggests that anti-dsDNA antibodies facilitate the pathogenesis of the disease process. However, the absence of anti-dsDNA antibodies cannot exclude the diagnosis of lupus as up to 15 to 35% of individuals with lupus test negative. Case Description: 24-year-old male presented with diffuse swelling and hypertensive urgency refractory to recent initiation of anti-hypertensives. Physical exam revealed a discoid, hypopigmented rash on both shoulders, non-scarring alopecia areata, and anasarca. Work-up revealed nephrotic range proteinuria, elevated Scr, and hypoalbuminemia. ANA 1:160, low C3 and C4, negative anti-dsDNA antibodies, and positive anti-Smith antibodies. Renal biopsy showed an abundance of immune complex deposits on electron microscopy consistent with class V lupus nephritis. The patient was initiated on high-dose steroids, mycophenolate mofetil, hydroxychloroquine, and atovaquone and discharged with outpatient follow-up. Discussion: Lupus nephritis is a secondary membranous nephropathy caused by the deposition of immune complexes derived from anti-dsDNA antibodies throughout the glomeruli. Depending on the test used, the specificity for anti-dsDNA antibodies ranges from 80 to 97%. Studies suggest that the presence of anti-Smith antibodies correlates with younger age of onset, higher rates of alopecia, and transaminitis. Male gender is associated with higher mortality rates as compared with female patients with similar baseline features and treatment. Renal involvement in SLE patients poses a higher mortality rate in cases presenting with acute kidney injury and those that fail to achieve remission at 1 year.Renal Biopsy 1A: EM, 1800X with multiple immune complex deposits 1B: EM, 4400X uranyl acetate staining multiple immune complex deposits and effacement of podocytes. Physical Exam Findings in Lupus Nephritis Patients (N=300) - Lupus Specific Findings: Malar rashPhotosensitive dermatitisGeneralized maculopapular rashDiscoid rash 80%50%26.67%20% Lupus non-specific findingsNon-scarring alopeciaOral ulcersVasculitic lesionsRaynauds phenomenon 86.67%56.67%33.34%6.67%