A51-47 Development of Severe Osmotic Demyelination Syndrome With Locked-in Syndrome Despite Appropriate Correction of Hyponatremia With Near Full Neurologic Recovery

Introduction Osmotic demyelination syndrome (ODS) is a rare but serious neurological condition typically caused by rapid correction of hyponatremia. Manifestations include altered consciousness, locked-in syndrome, impaired cranial nerve function, and quadriparesis. Limited case studies discuss function after recovery. Prognosis of ODS is variable, ranging from fatal to complete recovery. We present a case of ODS in a patient with severe neurologic deficits who experienced near complete recovery of all neurologic functions. Case Presentation A 39-year-old female with history of severe alcohol use disorder presented with paraparesis, gait instability, dysarthria, and urinary incontinence. The patient was hospitalized one week prior for severe hyponatremia and acute kidney injury. The admission and discharge serum sodium were 103 and 138 mEq/L, respectively, with daily correction not exceeding 4-6 mEq/L. On neurological evaluation, she was alert but had decreased gag reflex and 2/5 muscle strength in all four extremities. Labs were unremarkable on readmission. Brain magnetic resonance imaging (MRI) revealed acute demyelination in the central pons. Over 7 days, she had worsening bulbar function with loss of tongue movement, drooling, and concern for silent aspiration. She was intubated for airway protection. Her muscular weakness progressed until she could only move ocular muscles vertically to communicate yes/no answers, but her cognition remained intact. Early tracheostomy was pursued. She started bedside physical therapy and one month later, she regained muscle control of facial motion and posterior neck. She was discharged to a long-term acute care hospital (LTACH) after a 35-day hospital admission. At LTACH, she underwent inpatient rehab with physical therapy for 32 days and showed marked recovery, eventually being able to walk and run with minor impairments in gait and balance. Discussion Our patient presented with MRI findings of central pontine demyelinosis and then progressed to severe neurologic deficits with locked-in syndrome. While her serum sodium was corrected at the recommended rate of < 4-6 mEq/L in a 24-hour period during the original hospitalization, she still progressed to ODS. Risk factors for ODS include female sex, alcohol use disorder, and severely low serum sodium. Her case reminds clinicians to maintain a clinical suspicion for ODS even after a conservative rate of sodium correction. She had minimal residual deficits at peak recovery that allowed her to return to independent living. Her outcome highlights that the possibility of a complete neurologic recovery should be included in discussions of prognosis for patients in similar clinical situations. This abstract is funded by: None