What are potential complications of severe hypernatremia?

Severe hypernatremia, defined as an elevated sodium concentration in the blood, can lead to significant neurological complications. The central nervous system is particularly sensitive to rapid changes in sodium levels because of the osmotic gradients that affect brain cells. When hypernatremia occurs, the brain cells may shrink as water is drawn out of them due to the high sodium levels in the extracellular space. This shrinkage can result in neurological deficits, which may manifest as confusion, lethargy, or altered mental status. Moreover, if sodium levels rise significantly and acutely, the risk of seizures increases, as the altered osmotic balance affects neuronal excitability. Therefore, complications associated with severe hypernatremia primarily involve neurological issues, which is why the first option about neurological deficits and seizures is the correct answer.