Which of the following is a symptom of Hypernatremia?

Hypernatremia, which refers to an elevated level of sodium in the blood, can lead to various neurological symptoms due to changes in fluid balance and osmotic pressure in the brain. One of the key symptoms of hypernatremia is seizures. This occurs because hypernatremia can cause cellular dehydration, particularly in the central nervous system, leading to excitability of neurons and potentially resulting in seizures.

Looking at the other options, while fatigue and constipation can occur in various electrolyte imbalances and other conditions, they are not specific indicators of hypernatremia. Joint pain is typically unrelated to sodium levels, as it generally relates to inflammation or injury rather than an electrolyte imbalance. Therefore, seizures stand out as a significant and concerning symptom directly associated with increased sodium levels in the body.