From the Guidelines
Hyponatremia management guidelines are straightforward: correct serum sodium levels gradually, with a goal rate of increase of 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to prevent osmotic demyelination syndrome (ODS).
Management Strategies
- Mild hyponatremia (Na 126-135 mEq/L): does not require specific management apart from monitoring and water restriction 1
- Moderate hyponatremia (120-125 mEq/L): water restriction to 1,000 mL/day and cessation of diuretics is recommended 1
- Severe hyponatremia (<120 mEq/L): a more severe restriction of water intake with albumin infusion is recommended 1
- Hypovolemic hyponatremia: treatment is the discontinuation of diuretics and/or laxatives and providing fluid resuscitation, typically with 5% IV albumin or crystalloid (preferentially lactated Ringer’s) solution 1
- Euvolemic hyponatremia: should be managed based on the specific underlying cause 1
- Hypervolemic hyponatremia: treatment includes fluid restriction, reduction or discontinuation of diuretics and laxatives, administration of hyperoncotic albumin, and/or vasopressin receptor antagonists (“vaptans”) 1
Pharmacological Treatment
- Vasopressin receptor antagonists: can raise serum sodium during treatment, but should be used with caution only for a short term (≤30 days) 1
- Hypertonic saline: is reserved for short-term treatment of patients with symptomatic or severe hyponatremia or those with imminent liver transplantation (LT) 1
- Tolvaptan: has been approved for the management of severe hypervolemic hyponatremia (<125 mmol/L) associated with cirrhosis, ascites, heart failure, and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) 1
Key Considerations
- Correction rate: the goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to ameliorate the risk of ODS 1
- Monitoring: close clinical monitoring and assessment of serum sodium levels are necessary to avoid complications such as hypernatremia, dehydration, and renal impairment 1
From the Research
Guidelines for Management of Hyponatremia
The management of hyponatremia involves treating the underlying cause and categorizing patients according to their fluid volume status (hypovolemic, euvolemic, or hypervolemic) 2, 3, 4, 5.
- For most patients, the approach to managing hyponatremia should consist of treating the underlying cause.
- Urea and vaptans can be effective treatments for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but have adverse effects 2, 3.
- Severely symptomatic hyponatremia (with signs of somnolence, obtundation, coma, seizures, or cardiorespiratory distress) is a medical emergency and should be treated with bolus hypertonic saline to reverse hyponatremic encephalopathy by increasing the serum sodium level by 4 mEq/L to 6 mEq/L within 1 to 2 hours but by no more than 10 mEq/L (correction limit) within the first 24 hours 2, 6, 5.
Treatment Approaches
Different treatment approaches are recommended based on the severity and symptoms of hyponatremia:
- Asymptomatic mild hyponatremia: adequate solute intake with an initial fluid restriction (FR) of 500 ml/day adjusted according to the serum sodium (sNa) levels 3.
- Symptomatic hyponatremia: rapid intermittent administration of hypertonic saline is preferred for treatment 3, 6.
- Hyponatremic encephalopathy: a 100-ml bolus of 3% sodium chloride (513 mEq/L) administered in repeated doses until symptoms reverse, with the goal of increasing the serum sodium 5-6 mEq/L 6.
Monitoring and Correction
Close monitoring and gradual correction of serum sodium levels are crucial to prevent overcorrection and its consequences:
- The rate of correction is dependent upon the duration, degree of hyponatraemia and the presence or absence of symptoms 5.
- Excessive rapid correction should be avoided in both acute and chronic hyponatraemia, because it can lead to irreversible neurological complications including central osmotic demyelination 2, 5.