From the Guidelines
The goal correction of hypernatremia should be to reduce serum sodium by 10-15 mmol/L per 24 hours to avoid cerebral edema and neurological injury. This approach is based on the most recent guidelines, specifically the 2018 espghan/espen/espr/cspen guidelines on pediatric parenteral nutrition: fluid and electrolytes 1. The correction rate is crucial as rapid correction can lead to severe complications.
Key Considerations
- The therapeutic measures should be based on the etiology of hypernatremia, which can often be iatrogenic, especially in very low birth weight infants (VLBWI) 1.
- Assessment of the infant's intravascular volume and hydration status is essential to guide the treatment approach.
- In cases of symptomatic hypovolemia, plasma volume should be replaced to ensure adequate circulation before addressing the hypernatremia.
- The choice of fluid for correction depends on the patient's volume status, but hypotonic fluids are generally used for the gradual correction of hypernatremia.
Monitoring and Adjustment
- Frequent monitoring of serum sodium levels is critical, typically every 2-4 hours initially, to adjust the treatment plan as needed and prevent overcorrection or undercorrection.
- The treatment plan should be tailored to the individual patient's response to therapy, adjusting the rate of correction based on serum sodium levels and clinical status.
Potential Complications
- Correcting hypernatremia too rapidly can cause cerebral edema, seizures, and neurological injury, as the brain cells that have adapted to the hyperosmolar state may swell when serum osmolality decreases too quickly 1.
- Conversely, correcting too slowly can prolong the risk of hypernatremia-related complications, including seizures, brain hemorrhage, and death, emphasizing the need for a balanced approach to correction.
From the Research
Definition and Causes of Hypernatremia
- Hypernatremia is defined as a serum sodium level above 145 mmol/L 2
- It can be caused by insufficient free water intake, or excess free water losses 3
- The human body maintains a normal osmolality between 280 and 295 mOsm/kg via Arginine Vasopressin (AVP), thirst, and the renal response to AVP; dysfunction of all three of these factors can cause hypernatremia 2
Management and Correction of Hypernatremia
- The management of hypernatremia focuses on resolving the underlying cause, replenishing free water deficit, and preventing further losses while closely monitoring serum sodium concentration 3
- The goals for the correction rate of hypernatremia are less well established compared to hyponatremia 4
- Accurate diagnosis and appropriate treatment is crucial since undercorrection or overcorrection of hypernatremia are both associated with poor patients' prognosis 5
- A detailed algorithm for the proper correction of hypernatremia is necessary, taking into account the pathogenetic mechanisms and the evaluation of patients with increased sodium levels 5
Importance of Proper Correction
- Failure to correct hypernatremia can lead to central nervous system dysfunction 4
- Overcorrection of hypernatremia can also lead to significant symptoms and poor outcomes 4
- It is essential to stay within specific limits for correction, although these limits are not as well established for hypernatremia as they are for hyponatremia 4