Hypernatremia in Newborns: A Practical Approach to Management

Abstract

Hypernatremia is a potentially serious condition in both term and preterm babies, which can lead to severe and permanent neurological damage. There are many physiological changes in sodium homeostasis that occur soon after birth. Understanding this physiological process, early anticipation of hypernatremia and familiarization with the neonatal management of hypernatremia can prevent mortality and long-term morbidity associated with this condition. This review aims to provide a practical and understandable approach to the diagnosis and management of hypernatremia in neonates.

Keywords: Dehydration; Neonate; Preterm; Sodium.

Fig. 1

Schematic representation of the effect of hyper- and hypo-osmolality of ECF and ICF compartments. a Under normal conditions, water freely moves between ICF and ECF (IF and plasma). b If plasma fluid becomes hypotonic due to hypotonic fluids administered rapidly in the setting of chronic hypernatremia, water moves towards ICF due to the presence of osmolytes, causing cellular swelling and cerebral edema, clinically manifesting as encephalopathy and cerebral pontine Myelinosis. c Hypertonic plasma attracts more water from the ICF causing cellular distortion and shrinkage, resulting in intracerebral bleed, which clinically manifests as seizures and irritability.

Fig. 2

Schematic representation for IV fluid management according to serum sodium levels and timings for blood tests frequency.

Fig. 3

Serum sodium level in the first 5 days and other useful parameters for monitoring in ELBW babies (see text for explanation).