Neuroimaging Spectrum of Severe Hypernatremia in Infants with Neurological Manifestations

Abstract

Background 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. Methods 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. Results 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). Conclusion 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.

Postoperative hypernatremia is associated with worse brain injuries on EEG and MRI following pediatric cardiac surgery

“…We found that hypernatremia was associated with the MRI degree of brain injuries and almost all (93.3%) patients with hypernatremia had subdural hemorrhage. The primary consequence of hypernatremia is the shrinkage of cerebral cells that resulting in the brain being pulled away from the overlying calvarium, leading to the tearing of bridging veins and the occurrence of extensive subdural hemorrhage (30,31). Our data further showed that hypernatremia was associated with increase occurrence of white matter injury.…”

“…Our data further showed that hypernatremia was associated with increase occurrence of white matter injury. In a previous study on severe hypernatremia (serum sodium >160 mmol/L) in infants showed the incidence of white matter injuries was up to 70% (31). Experimental data in rats have demonstrated that acute hypernatremia can result in enduring histological brain damage, which includes myelinolysis of the white matter and neuronal necrosis (32).…”

Fatal Hypernatremic Dehydration in a Term Exclusively Breastfed Newborn

“…Infants with sodium levels of 150 mEq/L and above should be offered a brain MRI during admission, given that 45.2% are positive for lesions consistent with injury at this level [ 11 , 77 ]. They should also be offered developmental follow-up evaluation given the known increased risk of developmental problems associated with sodium levels ≥ 150 mEq/L [ 56 , 57 , 58 , 59 ].…”