Guillain-Barré Syndrome as Initial Presentation of Systemic Lupus Erythematosus: A Rare Diagnostic Challenge

Background: Guillain-Barré Syndrome (GBS) is a rare but serious autoimmune disorder that typically follows an infection and presents with ascending weakness and areflexia. Systemic Lupus Erythematosus (SLE), a multisystem autoimmune disease, may uncommonly manifest initially with GBS, posing diagnostic and therapeutic challenges. Case presentation: We report a 25-year-old female who presented with progressive limb weakness diagnosed as acute inflammatory demyelinating polyradiculoneuropathy (AIDP). She failed to respond to standard GBS therapies, including plasmapheresis and IVIG. During hospitalization, she developed features suggestive of systemic involvement including rash, oral ulcers, and nephrotic-range proteinuria. Further investigations revealed positive ANA and anti-dsDNA antibodies, low complement levels, and lupus nephritis (Class V) on renal biopsy, confirming SLE. Immunosuppressive treatment with steroids and mycophenolate mofetil led to clinical improvement. Conclusion: This case highlights the importance of considering autoimmune etiologies like SLE in patients with atypical or treatment-refractory GBS. Early recognition and initiation of immunosuppressive therapy are essential for optimal neurological and systemic outcomes.