Hypernatremia in newborns
Last reviewed: 23.04.2024
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[What causes hypernatremia in newborns?
Hypernatremia develops if the loss of water exceeds sodium loss (hypernatremic dehydration), if sodium intake exceeds its loss (salt poisoning) or both. The causes of water loss exceeding sodium loss are most often diarrhea, vomiting, or high fever. It can also develop due to feeding problems in the first days of life, and can also develop in children with very low birth weight (OHMT), born at the gestation period of 24-28 weeks. In OHMT children, imperceptible loss of water through an immature, water-permeable stratum corneum combined with immature kidney function and reduced ability to concentrate urine increase the loss of free water. Insensible loss of water through the skin also increases greatly when the child is under a radiant heat source, as well as with phototherapy; in such conditions, ONMT children may need intravenously up to 250 ml / (kg x day) of water in the first few days, after which the stratum corneum develops and the imperceptible loss of water decreases.
Excessive salt intake is most often the result of the addition of too much salt in the preparation of infant formula or the introduction of hyperosmolar solutions. Freshly frozen plasma and albumin contain sodium and can lead to hypernatremia if re-injected into deeply premature infants.
Symptoms of hypernatremia in newborns
Symptoms of hypernatremia include lethargy, anxiety, hyperreflexia, muscle hypertonia and convulsions. The main complications are intracranial hemorrhage, thrombosis of the venous sinus and acute necrosis of the renal tubules.
The diagnosis of "gipernatremia" is based on symptoms and signs and is confirmed by measuring the concentration of sodium in the blood serum. Additional laboratory changes may include increased urea nitrogen in the blood, a moderate increase in glucose, as well as a low level of potassium, a decrease in the level of serum calcium.
Treatment of hypernatremia in newborns
Treatment is carried out by intravenous injection of a glucose solution / 0.3-0.45% sodium chloride in amounts equal to the deficit of fluid that are introduced 2-3 days in order to avoid a rapid decrease in blood serum osmolality, which can cause a rapid flow of water into the cells and potentially can lead to brain edema. The goal of the treatment is to reduce serum sodium by about 10 meq / day. Regular body weight, blood serum electrolytes, volume and specific gravity of urine should be monitored, which allows you to correct the volume of the fluid you inject. Supporting solutions must be administered simultaneously.
High hypernatremia (sodium more than 200 meq / L) caused by salt poisoning should be treated with peritoneal dialysis, especially if the poisoning leads to a rapid increase in serum sodium.
How is hypernatremia prevented in newborns?
Prevention requires attention to the volume and composition of unusual fluid losses and solutions used to maintain homeostasis. In newborns and infants who are unable to effectively make it clear that they are thirsty and need to compensate for fluid loss, the risk of dehydration is greatest. The composition of the food, if mixtures are diluted (for example, some infant formulas or concentrated feed mixtures) require special attention, especially if there is a high risk of dehydration, for example during episodes of diarrhea, low fluid intake, vomiting, or high fever.