From the Guidelines
Hypernatremia should be treated by addressing the underlying cause and correcting sodium levels gradually, with a recommended reduction rate of 10-15 mmol/L/24h to prevent cerebral edema, seizures, and neurological injury. The causes of hypernatremia are often iatrogenic, resulting from incorrect replacement of transepidermal water loss, inadequate water intake, or excessive sodium intake, especially in very low birth weight infants 1.
Key Considerations
- Assessment of the patient's intravascular volume and hydration status is crucial in determining the therapeutic approach 1.
- In cases of symptomatic hypovolaemia, plasma volume should be replaced 1.
- A rapid correction of hypernatremia can lead to severe complications, emphasizing the need for a controlled reduction in sodium levels 1.
Treatment Approach
- The treatment should be based on the aetiology of hypernatremia, focusing on correcting the underlying cause 1.
- For patients with hypernatremia, especially those who are symptomatic or have severe hypernatremia, careful monitoring of serum sodium, fluid status, and neurological signs is essential during treatment.
- The use of hypotonic fluids, such as 0.45% saline or 5% dextrose in water, may be necessary for intravenous administration in severe cases or when oral intake is not possible.
Ongoing Management
- Ongoing monitoring and adjustments in treatment are critical to ensure that the correction of sodium levels is proceeding safely and effectively.
- The calculation of fluid replacement volume can be guided by formulas that account for total body water deficit, helping to tailor the treatment to the individual patient's needs.
From the Research
Causes of Hypernatremia
- Hypernatremia is a common electrolyte disorder that reflects an imbalance in the water balance of the body, often resulting from an increased loss of free water compared to sodium excretion 2
- It is rarely based on excessive sodium intake 2
- Causes of hypernatremia include dehydration resulting from an impaired thirst mechanism or lack of access to water, diabetes insipidus, and other possible causes 3
- Hypernatremia can be caused by excessive loss of solute-free water or decreased fluid intake, and less often, the aetiology is salt intoxication 4
Symptoms of Hypernatremia
- The clinical presentation is often characterized by a central nervous system dysfunction (confusion, coma) and pronounced thirst (in awake patients) 2
- Symptoms can range from mild to severe, including nausea, vomiting, weakness, headache, and mild neurocognitive deficits 3
Treatment of Hypernatremia
- Treatment starts with addressing the underlying etiology and correcting the fluid deficit 3
- When sodium is severely elevated, patients are symptomatic, or intravenous fluids are required, hypotonic fluid replacement is necessary 3
- The treatment of hypernatremia - in addition to addressing the underlying cause - is replacing the (absolute or relative) loss of free water by hypotonic infusions, or in case of diabetes insipidus, by application of Desmopressin (Minirin) 2
- Correction of hypernatremia must be slow to prevent cerebral oedema and irreversible brain damage 4
- Preexisting hypernatremia (>48h) should not be reduced by more than 8-10 mmol/l/day 2
- For acute hypernatremia (< 24 hours), hemodialysis is an effective option to rapidly normalize the serum sodium levels 2
Management of Hypernatremia
- Management to correct sodium concentration is based on whether the patient is hypovolemic, euvolemic, or hypervolemic 3
- Physicians may apply some of the steps to all patients with hypernatremia, and can also adapt the regimens for specific causes or situations 5
- The eight diagnostic steps of the traditional approach to hypernatremia include: exclude pseudohypernatremia, confirm glucose-corrected sodium concentrations, determine the extracellular volume status, measure urine sodium levels, measure urine volume and osmolality, check ongoing urinary electrolyte free water clearance, determine arginine vasopressin/copeptin levels, and assess other electrolyte disorders 5
- Six steps to manage hypernatremia include: identify underlying causes, distinguish between acute and chronic hypernatremia, determine the amount and rate of water administration, select the type of replacement solution, adjust the treatment schedule, and consider additional therapy for diabetes insipidus 5