What is a common cause of hypernatremia?

Hypernatremia refers to an elevated sodium concentration in the blood and is often indicative of a water imbalance in the body. A common cause of hypernatremia is a free water deficit, which occurs when there is insufficient water relative to sodium in the body. This situation can arise from various factors, such as excessive loss of water due to sweating, diarrhea, or inadequate intake of water.

When the body lacks adequate free water, the concentration of sodium increases, leading to hypernatremia. It is important to recognize that hypernatremia primarily develops through a relative deficit of water rather than an absolute increase in sodium, which is why a free water deficit is highlighted as a common cause.

In conditions where there is excessive water intake, it typically leads to dilution of sodium, which would decrease sodium levels rather than increase them. Increased sodium excretion can also counteract hypernatremia by facilitating the removal of excess sodium through the kidneys. Dehydration can contribute to hypernatremia, but it is more specifically tied to the loss of water rather than just a reduction in overall fluid intake. Hence, focusing on the concept of a free water deficit provides a clearer understanding of the underlying mechanism leading to hypernatremia.