Extrapontine myelinolysis of favorable outcome in a patient with autoimmune polyglandular syndrome

INTRODUCTION: Extrapontine myelinolysis is a well-known complication of hyponatremia and its treatment. It rarely occurs without central pontine myelinolysis, usually after overly rapid correction of hyponatremia. Its prognosis is considered poor. EXEGESIS: We report the case of a patient with autoimmune polyglandular syndrome with subacute adrenal failure responsible of severe hyponatremia. Despite a well-conducted treatment, the patient developed acute anxiety, catatonia, dysphagia and parkinsonism revealing extrapontine myelinolysis demonstrated on MRI. Outcome was favorable. CONCLUSION: Extrapontine myelinolysis may occur in the absence of central pontine myelinolysis despite a treatment of hyponatremia conducted according to published guidelines. Treatment should be extremely cautious when hyponatremia has been lasting for more than 48 hours.