Chronic Guillain-Barré syndrome and refractory diarrhea after RYGB: a 9-year longitudinal case report.

We present a 46-year-old male who developed chronic Guillain-Barré syndrome and refractory diarrhea after undergoing Roux-en-Y gastric bypass, with progressive neurological deterioration and 34.9% total weight loss over 9 years. Serial evaluations demonstrated severe deficiencies include vitamin D, calcium, iron and other nutritions, accompanied by evidence of autoimmune dysregulation. The patient's condition progressed to require partial parenteral nutrition due to worsening neurological and gastrointestinal dysfunction. This case highlights the critical need for ongoing nutritional monitoring after bariatric surgery and suggests that persistent micronutrient deficiencies may contribute to sustained immune dysfunction, potentially triggering chronic autoimmune neurological disorders in susceptible individuals.