Central Pontine Myelinolysis and Hypokalemic Paralysis as Initial Manifestations of Primary Sjögren's Syndrome: A Rare Electrolyte-Mediated Neurological Presentation.

A 63-year-old woman presented with acute quadriparesis and severe hypokalemia (2.07 meq/L) secondary to distal renal tubular acidosis (dRTA), which was later attributed to primary Sjögren's syndrome (SS). Brain MRI revealed a characteristic trident-shaped hyperintense lesion in the central pons on T2-weighted and fluid-attenuated inversion recovery (FLAIR) sequences, consistent with central pontine myelinolysis (CPM). The patient had no history of rapid sodium correction, suggesting hypokalemia as the primary trigger for CPM. She was treated with intravenous potassium replacement and intravenous methylprednisolone, followed by oral steroids and hydroxychloroquine. Her neurological symptoms resolved completely within one month, and follow-up MRI showed only residual gliosis. This case highlights two rare neurological manifestations of SS - hypokalemic paralysis and CPM - both resulting from electrolyte disturbances rather than direct autoimmune-mediated nerve damage. While peripheral neuropathy is the most common neurological complication of SS, central nervous system involvement, particularly CPM, is exceedingly rare. This report emphasizes the importance of considering SS in patients with unexplained hypokalemia and acute neurological deficits, as timely diagnosis and treatment can lead to favorable outcomes.