Which electrolyte imbalance might occur in a patient experiencing dehydration?

Dehydration typically leads to a concentration of solutes in the blood since the loss of water results in a relative increase of certain electrolytes. Hypernatremia, which is an elevated level of sodium in the blood, is a common consequence of dehydration. This occurs because when a patient becomes dehydrated, their body loses water without losing sodium at the same rate, leading to a higher concentration of sodium in the bloodstream.

In contrast, options such as hyperkalemia (high potassium levels) and hypocalcemia (low calcium levels) are less commonly associated with dehydration specifically and would typically relate to different underlying health issues or imbalances. Hyponatremia, characterized by low sodium levels, is more associated with conditions involving excessive water retention rather than dehydration. Thus, hypernatremia is the expected outcome when dehydration occurs, making it the correct answer.