5. Which finding may require emergency treatment of SIADH? A. Significant neurologic changes B. Serum sodium level of \( 125 \mathrm{mEq} / \mathrm{L} \) C. Serum sodium level of \( 135 \mathrm{mEq} / \mathrm{L} \) D. 4+ pitting edema in all extremities

The correct answer is **A. Significant neurologic changes**. In the context of SIADH (Syndrome of Inappropriate Antidiuretic Hormone secretion), significant neurologic changes can indicate severe hyponatremia (low sodium levels), which can lead to serious complications such as seizures, coma, or even death. While a serum sodium level of \( 125 \mathrm{mEq} / \mathrm{L} \) (option B) is indeed low and may require treatment, the presence of significant neurologic changes is a more urgent indicator that emergency treatment is necessary. Option C (serum sodium level of \( 135 \mathrm{mEq} / \mathrm{L} \)) is within the normal range and does not require emergency treatment. Option D (4+ pitting edema in all extremities) may indicate fluid overload but is not as immediately life-threatening as significant neurologic changes.