What is the cause of sacral pitting edema in a patient with hypovolemic hypernatremia? I am a medical student and I have this case to solve.

Sacral pitting edema. Sacral pitting edema is common in bedbound patients due to gravitational pooling of fluids. If there is no history of recent diarrhea or vomiting, i would suspicious of loop diuretic in CHF patient causing this problem.