A 42-year-old man is stranded in the desert for 2 days without water. He is severely dehydrated and has serum sodium of 158 mEq/L. Which fluid compartment change best explains his condition?
A
Isosmotic expansion of extracellular fluid only
B
Hyperosmotic contraction of both extracellular and intracellular compartments
C
Hyposmotic expansion of intracellular compartment only
D
Isosmotic contraction of intracellular compartment only