From the Guidelines
Hypernatremia is often caused by iatrogenic factors, particularly in very low birth weight infants, resulting from incorrect replacement of transepidermal water loss, inadequate water intake, or excessive sodium intake. The causes of hypernatremia can be broadly categorized into two main groups: water loss exceeding sodium loss or excessive sodium intake 1.
Common Causes
- Inadequate water intake due to impaired thirst mechanism, limited access to water, or altered mental status
- Water losses through the kidneys, gastrointestinal tract, respiratory system, or skin
- Iatrogenic causes such as administration of hypertonic fluids or excessive sodium in tube feedings
Iatrogenic Causes
Iatrogenic causes are particularly significant in pediatric patients, as noted in the espghan/espen/espr/cspen guidelines on pediatric parenteral nutrition: fluid and electrolytes 1.
Clinical Considerations
It is essential to assess the infant's intravascular volume and hydration status to determine the underlying cause of hypernatremia and guide therapeutic measures 1. A reduction rate of 10-15 mmol/l/24 h is recommended to avoid rapid correction, which may induce cerebral edema, seizures, and neurological injury 1.
From the Research
Causes of Hypernatremia
- Hypernatremia can result from pure sodium excess but is usually associated with dehydration, secondary to excess losses of water or hypotonic fluids 2
- It can be caused by impaired water ingestion, although increased water losses are often contributory 3
- Diabetes insipidus may lead to free water loss, hypernatremia, and volume depletion 4
- Hospital-acquired hypernatremia is usually iatrogenic because of inadequate water prescription and is therefore preventable 3
- Other causes of hypernatremia include dehydration resulting from an impaired thirst mechanism or lack of access to water 5
Associated Conditions
- Hypernatremia is associated with high morbidity and mortality, both as a result of the underlying disease and inadequate treatment 3
- It is less common than hyponatremia but is associated with the highest morbidity and mortality rate, primarily related to CNS dysfunction 2
- Hypernatremia and hyponatremia are associated with worse outcomes and longer intensive care stays 4