A Clinical Analysis Of 4 Cases With Osmotic Demyelination Syndrome

Background Osmotic demyelination syndrome is a secondary demyelinating disease,also called osmotic myelinolysis syndrome,including central pontine myelinolysis and extrapontine myelinolysis.The exact cause and etiopathogenesis of this disease is not clear,the majority of patients have serious underlying diseases,such as chronic alcoholism,malnutrition,liver transplantation,especially a rapid correction of hyponatremia may easily cause it because the excessive hypertonic saline make a rapid increase in plasma osmotic pressure when the brain cells in a hypotonic state.It causes brain dehydration and blood-brain barrier is damaged,which may result in demyelination that related to toxic substances.Therefore,it is suggested that this is a kind of "iatrogenic results". As the disease is still rare, and there are too many causes not confirmed, it may occur in any clinical department.The dominant feature is that the clinical manifestations is not synchronized with MRI lesions.There is a 1-2 weeks or even longer time gap between them,so it is easy to cause misdiagnosis and missed diagnosis and then delay treatment.This case analysis may have much sense of improving the awareness of the disease to physicians, including earlier prevention, diagnosis and treatment.Objectives To investigate the etiology, etiopathogenesis, clinical manifestations, MRI characteristics and the principles of prevention and treatment of osmotic demyelination syndrome.Methods Reviewed all the clinical materials of the four cases with osmotic demyelination syndrome,and analyzed their etiology, clinical manifestations, MRI characteristics and treatment methods objectively to reach a final summary.Results (1)1 had liver transplantation,1 had lung cancer(non-small cell cancer comfimed by biopsy),1 had epidural hematoma after brain injury,1 was a postoperative patient with pituitary adenoma, the latter 3 cases existed rapid correction of hyponatremia; (2)1case started with coma, dysarthria, and movement disorders was showed as the earliest clinical features in 2 cases,1 case showed delirium status; (3) Pseudobulbar palsy appeared in 3 cases.2 cases showed Parkinson's syndrome, all 4 cases had limb paralysis; (4) 2 cases showed central pontine myelinolysis in MRI,1 case showed central pontine myelinolysis combined with extrapontine myelinolysis (bilateral striatum and bilateral thalamus),1 case showed extrapontine myelinolysis (bilateral striatum) with subcortical damage (bilateral frontal and temporal lobe); (5) 4 cases were treated with high-dose methyl-prednisolone and symptomatic supportive care, while 1 case for plasma exchange,1 was treated with hyperbaric oxygen therapy; (6) 3 cases' neurological function fully recovered,1 patient showed persistent vegetative state.Conclusions (1) Osmotic demyelination syndromeis is relatively rare,and many patients have serious underlying diseases, especially is highly related to rapid correction of hyponatremia;(2) Pseudobulbar and Parkinson's syndrome are the common clinical manifestation, mental disorders can be the first symptom;(3) MRI examination reveals the base of the pons, striatum, thalamus and cortex can be victimized;(4) osmotic demyelination syndrome is a preventable and curable diseases, emphasis on risk factors, given comprehensive treatment, most of their prognosis is good.