**Core Concept**
Dialysis disequilibrium occurs when there is a rapid shift of water from brain cells to the bloodstream during the initiation of dialysis, leading to cerebral edema and neurological symptoms. This phenomenon is primarily due to the difference in the rate of diffusion of water and solutes across the blood-brain barrier.

**Why the Correct Answer is Right**
During dialysis, the removal of urea and other solutes from the bloodstream creates an osmotic gradient that causes water to move out of the brain cells into the bloodstream. This rapid shift of water can lead to cerebral edema and increased intracranial pressure, resulting in symptoms such as headache, nausea, and vomiting. The blood-brain barrier's limited permeability to water and solutes exacerbates this issue.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not relate to the pathophysiology of dialysis disequilibrium.
**Option B:** This option is incorrect because it refers to a different condition, not related to dialysis.
**Option C:** This option is incorrect because it is a treatment option for dialysis disequilibrium, not the cause.

**Clinical Pearl / High-Yield Fact**
To minimize the risk of dialysis disequilibrium, it is essential to gradually reduce the sodium concentration in the dialysate to prevent sudden shifts in water and solutes.

**Correct Answer:** C.