Neuroimaging Spectrum of Severe Hypernatremia in Infants with Neurological Manifestations

Variable neurological manifestations and imaging findings have been described in children with severe hypernatremia. We aimed to describe the spectrum of neuroimaging changes in infants with severe hypernatremia.

This retrospective study included infants with severe hypernatremia (serum sodium >160 mEq/L), abnormal neurological examination, and an abnormal magnetic resonance imaging (MRI) of the brain over a period of 2 years in a tertiary care hospital. Relevant clinical data, including the feeding practices, clinical features, complications, and biochemical and radiological parameters, were entered in a structured pro forma. MRI findings were classified as vascular (hemorrhages and cerebral sinus venous thrombosis), osmotic demyelination syndrome (pontine and extrapontine myelinolyses), and white matter changes.

The common clinical features in the neonates were poor feeding (n = 4) and decreased urine output (n = 4); the older infants presented with gastrointestinal losses (n = 5). All cases had dehydration with encephalopathy. The patterns of radiological injury were vascular (hemorrhages, n = 5 and venous thrombosis, n = 3), osmotic demyelination (n = 8), and white matter changes (n = 7). Coagulopathy was correlated with the vascular complications (r = 0.8, p < 0.0001); the degree of dehydration was correlated with the venous thrombosis (r = 0.7, p < 0.04) and acute kidney injury (r = 0.8, p < 0.001). Neurological sequelae were seen in four cases and correlated with hypernatremia (r = 0.6, p = 0.03) and hyperosmolarity (r = 0.6, p = 0.03).

Characteristic neuroimaging findings are vascular changes in the form of venous thrombosis and hemorrhages, osmotic demyelination and white matter tract injury, and/or mostly combinations of these findings. Severe hypernatremia and resulting hyperosmolarity frequently cause neurological sequelae in neonates and infants.