From the Guidelines
Hypernatremia is primarily caused by iatrogenic factors, including incorrect replacement of transepidermal water loss, inadequate water intake, or excessive sodium intake, particularly in vulnerable populations such as very low birth weight infants (VLBWI) 1. The causes of hypernatremia can be multifaceted, involving either water loss exceeding sodium loss or excessive sodium intake. Key factors include:
- Inadequate water intake due to altered thirst mechanisms, impaired access to water, or inability to communicate thirst, commonly seen in elderly, infants, or unconscious patients.
- Water losses through various pathways such as the kidneys (e.g., diabetes insipidus, osmotic diuresis from hyperglycemia, or diuretic use), gastrointestinal tract (vomiting, diarrhea), skin (excessive sweating, burns), or respiratory system (tachypnea).
- Iatrogenic causes, including the administration of hypertonic saline or sodium bicarbonate, or excessive sodium in tube feedings or medications, as highlighted in the context of pediatric parenteral nutrition 1. It's crucial to ascertain the etiology of hypernatremia by assessing the patient's intravascular volume and hydration status to guide therapeutic measures, ensuring a careful correction of sodium levels to prevent complications such as cerebral edema, seizures, and neurological injury, with a recommended reduction rate of 10-15 mmol/L/24 hours 1.
From the Research
Causes of Hypernatremia
- Hypernatremia is often caused by an overall deficit of total body water 2
- It can also be caused by an impaired thirst mechanism or lack of access to water, leading to dehydration 3
- Other causes include:
- Hypernatremia can be acquired in both the hospital and community settings 2
- In rare cases, hypernatremia can result from gain of sodium chloride 5
- The clinical presentation is often characterized by a central nervous system dysfunction (confusion, coma) and pronounced thirst (in awake patients) 4