Lentiform fork sign in a uremic patient after inadvertent exposure to metformin

This case report describes a 56-year-old woman receiving regular hemodialysis for three years who presented with an unsteady gait for one month, dysarthria, and frequent choking on liquids for two weeks. Brain MRI revealed a characteristic “lentiform fork sign” with hyperintense T2W/FLAIR signal in the bilateral lentiform nuclei and restricted diffusion in bilateral globus pallidus. She was inadvertently prescribed metformin 1,000 mg per day one month ago by a physician who was unaware of her end-stage kidney disease. After intensive hemodialysis therapy with eight hemodialysis sessions within 12 days, her neurological deficits fully resolved. Clinicians should be aware of metformin-induced encephalopathy, presenting with relevant medication history, neurological symptoms, and the lentiform fork sign.