From Nerve to Autoimmunity: Acute Guillain-Barré Syndrome in a 4-Year-Old with Early-Onset Pediatric Systemic Lupus Erythematosus.

Objective: To report an unusual pediatric case of Guillain-Barré Syndrome (GBS) presented as the first manifestation of Systemic Lupus Erythematosus (SLE), highlighting diagnostic and clinical considerations. Methods: We document the clinical presentation, laboratory findings, diagnostic investigations, and management of a 4-year-old boy who presented with progressive weakness and sensory deficits. Initial Electrophysiology and cerebrospinal fluid analysis reveal GBS diagnosis while, autoimmune and renal workup revealed an underlying SLE. Results: We report a case of a 4-year-old boy who presented with progressive bilateral lower-limb weakness, absent deep tendon reflexes, sensory loss, and muscle weakness, confirmed as GBS through electrophysiological studies and cerebrospinal fluid analysis. Further investigations revealed thrombocytopenia, elevated antinuclear antibody titers, double-stranded DNA antibodies, proteinuria, and hematuria, leading to the diagnosis of SLE with GBS as the initial manifestation. The patient was referred for rheumatology and nephrology management and recovered from GBS but was diagnosed with SLE, complicated by membranous lupus nephritis (class V). Conclusion: GBS can rarely present as the first neurological manifestation of pediatric SLE. Early recognition and a multidisciplinary approach are critical for effective management and improved outcomes.