What is the result of excessive sodium reabsorption?

• A. Hyponatremia
• B. Hyperkalemia
• C. Fluid retention
• D. Metabolic alkalosis

Answer: (C)

Excessive sodium reabsorption leads to fluid retention due to the relationship between sodium and water in the body. When the kidneys reabsorb more sodium, they also tend to retain water in order to maintain osmotic balance. This increase in sodium levels and the accompanying water retention results in an expansion of the extracellular fluid volume, which can lead to conditions such as edema or hypertension.

In contrast, hyponatremia would occur if sodium levels were to drop, and hyperkalemia relates to elevated potassium levels rather than sodium retention. Metabolic alkalosis typically involves a decrease in hydrogen ions or an increase in bicarbonate, neither of which directly relate to the excessive reabsorption of sodium. Thus, fluid retention stands out as the most direct consequence of excessive sodium reabsorption.