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

Hypernatremia directly increases plasma albumin concentration, which lowers oncotic pressure and causes fluid to accumulate in tissues.

Excess sodium causes immediate intracellular water swelling that forces fluid into lymph channels producing pitting edema in distant tissues without changing extracellular osmolarity.

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.

Hypernatremia induces systemic vasodilation that passively traps water inside capillaries, preventing normal venous return and leading to localized edema only in dependent areas.