From the Research
Hypernatremia is primarily caused by a relative water deficit, often due to decreased thirst sensation, reduced water intake, or excessive water loss, rather than excessive sodium intake. This condition can arise from various factors, including inadequate water intake, especially in elderly or debilitated patients who cannot access water, excessive water loss through the kidneys (as seen in diabetes insipidus), gastrointestinal losses (such as severe diarrhea or vomiting), excessive sweating without adequate water replacement, and iatrogenic causes like the administration of hypertonic saline or sodium bicarbonate 1. Certain medications, including lithium, demeclocycline, and loop diuretics, can contribute to hypernatremia by interfering with the kidney's ability to concentrate urine. Endocrine disorders, such as Cushing's syndrome or primary hyperaldosteronism, can also lead to sodium retention, further contributing to hypernatremia 2.
The development of hypernatremia is a sign that the body's normal regulatory mechanisms have failed to maintain proper sodium balance, particularly when thirst mechanisms are impaired or access to water is limited. This condition is dangerous because it causes cellular dehydration as water moves out of cells into the hyperosmolar extracellular fluid, leading to brain cell shrinkage and neurological symptoms. The management of hypernatremia involves eliminating the causes of the condition and specifically managing body volume and electrolytes, with a focus on correcting the serum sodium concentration slowly to avoid CNS damage 3, 4.
Key points to consider in the management of hypernatremia include:
- Identifying and addressing the underlying cause of the water deficit or sodium excess.
- Correcting the serum sodium concentration slowly, with frequent monitoring of serum electrolytes to avoid rapid shifts that could lead to CNS damage.
- Providing adequate water intake or using intravenous fluids as appropriate to correct dehydration.
- Managing medications that may be contributing to hypernatremia.
- Monitoring for signs of CNS dysfunction and other complications of hypernatremia.
Given the potential for significant morbidity and mortality associated with hypernatremia, especially in the elderly and critically ill patients, accurate diagnosis and appropriate treatment are crucial 1. The most recent and highest quality study 1 emphasizes the importance of a practical guide for physicians in evaluating and treating hypernatremia, highlighting the need for specific directions in patient evaluation and a detailed algorithm for the proper correction of hypernatremia.