Iatrogenic hyponatremia in pediatrics: pathophysiology, classification and prevention

Dovile Gineityte1, Greta Habdanke1 

1Lithuanian University of Health Sciences, Medical Academy, Faculty of Medicine, Kaunas, Lithuania


Introduction. Hyponatremia – it is an electrolyte natrium disbalance and it appears when serum natrium concentration decreases to <135 mmol/l. The development of iatrogenic hyponatremia is still a serious problem in clinical practice, often associated with infusion therapy in children.

Aim: to review the available scientific literature and discuss the development, classification and severity assessment of iatrogenic hyponatremia. To discuss the relationship between old and new fluid therapy guidelines and the correlation with iatrogenic hyponatremia.

Methods: scientific articles were searched in the databases PubMed, UpToDate and the articles from 2011 to 2021 were chosen in English language.

Results. In hypovolemia, nausea, stress or pain, as well as with certain medications, non-osmotic secretion of ADH is promoted and dehydration is impaired, water and electrolyte disbalance and a decrease in serum sodium levels occurs, and administration of hypotonic intravenous solutions further promotes the development of hyponatremia. Hyponatremia is classified into hypotonic (serum osmolarity is less than 275 mosm/l), hypertonic (serum osmolarity is more than 295 mosm/l), and isotonic (it develops when there is hypercholesterolemia, hyperproteinemia or hypertriglyceridemia) according to serum tonicity. Mild hyponatremia occurs when serum natrium concentration is between 131 and 135 mmol/l, moderate, when the concentration is between 125 and 130 mmol/l and severe, when the concentration is below 125 mmol/l. Holliday and Segar calculated the metabolic fluid requirements and electrolytes for children, stating that the infusion solution should be based on glucose and the sodium content should be 3 mmol/kg/day. A strong association between hypotonic solution administered by Holliday and Segar metabolic rate calculations and developing iatrogenic hyponatremia has been observed. The new guidelines recommend the administration of an isotonic solution in order to prevent complications: hyponatremia, hypernatremia, and hyperchloremia. Metabolic infusion therapy should be isotonic and have adequate potassium and glucose levels.

Conclusions. The mechanisms for the development of iatrogenic hyponatremia are the release of non-osmotic factors induced ADH and the administration of hypotonic intravenous infusion solutions. Hyponatremia is classified into hypotonic, hypertonic, and isotonic, also into mild, moderate, and severe. Iatrogenic hyponatremia has been reported to be more common in pediatric patients due to hypotonic infusion. The new guidelines recommend the administration of isotonic solutions for the prevention of hyponatremia. The risk of isotonic solution-induced complications is very low.


Keywords: hyponatremia, iatrogenic hyponatremia, fluid therapy, pediatrics, children, pediatric intensive care.