From the Guidelines
Severe hyponatremia presents with serious neurological symptoms, including confusion, seizures, coma, and altered mental status, which can progress to respiratory arrest and brain herniation, and requires immediate medical attention 1. The symptoms of severe hyponatremia are primarily neurological due to brain cell swelling.
- Symptoms include severe headache, confusion, seizures, and altered mental status that can progress to coma.
- Patients may experience nausea and vomiting, muscle weakness, cramps or spasms, and fatigue.
- In critical cases, respiratory arrest and brain herniation can occur, which may be fatal. The severity of symptoms correlates with both the absolute sodium level and how quickly it developed, with rapid drops causing more dramatic symptoms, as noted in the context of marathon runners and endurance athletes 1. Acute hyponatremia (developing in less than 48 hours) typically produces more severe symptoms than chronic cases where the brain has had time to adapt. Risk factors include excessive water intake, certain medications (diuretics, antidepressants, antipsychotics), medical conditions (heart failure, kidney disease, SIADH), and endocrine disorders. Severe hyponatremia requires immediate medical attention as it constitutes a medical emergency requiring careful sodium correction to prevent osmotic demyelination syndrome, which can occur if sodium levels are corrected too rapidly, a consideration also relevant in the management of patients with liver cirrhosis 1. The most critical aspect of managing severe hyponatremia is the prompt recognition of its symptoms and the initiation of appropriate treatment to correct sodium levels carefully and avoid further complications 1.
From the FDA Drug Label
Patients should be in a hospital for initiation and re-initiation of therapy to evaluate the therapeutic response and because too rapid correction of hyponatremia can cause osmotic demyelination resulting in dysarthria, mutism, dysphagia, lethargy, affective changes, spastic quadriparesis, seizures, coma and death The symptoms of severe hyponatremia that can occur due to too rapid correction include:
- Dysarthria
- Mutism
- Dysphagia
- Lethargy
- Affective changes
- Spastic quadriparesis
- Seizures
- Coma
- Death 2
From the Research
Symptoms of Severe Hyponatremia
The symptoms of severe hyponatremia can be life-threatening and include:
- Somnolence
- Obtundation
- Coma
- Seizures
- Cardiorespiratory distress 3, 4, 5, 6 These symptoms occur due to the rapid movement of water into brain cells, resulting in cerebral edema, and are more pronounced in acute hyponatremia where brain adaptation is incomplete 6.
Diagnosis and Treatment
Severely symptomatic hyponatremia is a medical emergency that demands immediate recognition and intervention 3, 5. Treatment with bolus hypertonic saline is recommended to reverse hyponatremic encephalopathy by increasing the serum sodium level by 4 mEq/L to 6 mEq/L within 1 to 2 hours, but not exceeding a correction limit of 10 mEq/L within the first 24 hours 3, 7.
Important Considerations
Overly rapid correction of chronic hyponatremia can cause osmotic demyelination, a rare but severe neurological condition, which can result in parkinsonism, quadriparesis, or even death 3, 4, 7, 6. Therefore, it is essential to carefully monitor the correction of serum sodium levels to avoid these complications.