How can hypernatremia contribute to edema (excess tissue fluid)?

• A. Hypernatremia directly increases plasma albumin concentration, which lowers oncotic pressure and causes fluid to accumulate in tissues.
• B. Excess sodium causes immediate intracellular water swelling that forces fluid into lymph channels producing pitting edema in distant tissues without changing extracellular osmolarity.
• C. Elevated extracellular sodium raises extracellular osmolarity, pulling water out of cells into the extracellular/interstitial spaces and increasing tissue fluid volume, which presents clinically as edema.
• D. Hypernatremia induces systemic vasodilation that passively traps water inside capillaries, preventing normal venous return and leading to localized edema only in dependent areas.

Answer: (C)