From the Guidelines
Osmotic demyelination syndrome (ODS) typically presents with symptoms such as seizure, encephalopathy, dysarthria, dysphagia, oculomotor dysfunction, and quadriparesis, usually 2 to 7 days after rapid correction of serum sodium levels. The symptoms of ODS can be severe and debilitating, including neurological deficits that result from the destruction of the myelin sheaths insulating nerve fibers, particularly in the pons and sometimes in other brain regions 1.
Key Symptoms
- Seizure
- Encephalopathy
- Dysarthria (difficulty speaking)
- Dysphagia (difficulty swallowing)
- Oculomotor dysfunction (eye movement problems)
- Quadriparesis (weakness in all four limbs) These symptoms occur due to the osmotic stress caused by rapid changes in serum sodium levels, leading to demyelination and disruption of normal nerve signal transmission 1.
Risk Factors
The risk of developing ODS may be increased in patients with advanced liver disease, alcoholism, severe hyponatremia, malnutrition, and certain metabolic derangements such as hypophosphatemia, hypokalemia, or hypoglycemia 1.
Prevention and Management
Prevention of ODS is crucial, and this can be achieved by avoiding rapid correction of serum sodium levels, with a recommended goal rate of change of 4-8 mEq/L per day, not to exceed 10-12 mEq in a 24-hour period, or even lower in high-risk patients 1. If overcorrection occurs, relowering with electrolyte-free water or desmopressin may be considered, and the use of tromethamine may also reduce the risk of ODS 1.
From the Research
Symptoms of Osmotic Demyelination
The symptoms of osmotic demyelination syndrome can vary, but common manifestations include:
- Quadriparesis 2
- Neurocognitive changes 2
- Encephalopathy 3
- Dysphonia 3
- Extrapyramidal symptoms 3
- Seizures 3
- Mental retardation 3
- Pseudobulbar paralysis 3
Neuroimaging Characteristics
Neuroimaging results often show:
- Central pontine myelinolysis 4, 3
- Extrapontine myelinolysis 4, 3
- Combined central pontine myelinolysis and extrapontine myelinolysis 4, 3 Magnetic resonance imaging (MRI) is the diagnostic modality of choice, and diffusion tensor imaging is increasingly used for prognostication in osmotic demyelination syndrome 4.
Outcomes
The outcomes of osmotic demyelination syndrome can vary, with some patients showing:
- Complete neurological recovery 4
- Improvement after treatment 3
- No improvement after treatment 3
- Significant improvement after rehabilitation training 3 The prognosis is often favorable for patients who show symptoms of encephalopathy, and those who present with mental retardation, seizures, and no other symptoms may recover better than their counterparts who have other symptoms 3.