There are choices for this question namely:
1. Decreased serum sodium level
2. Decreased serum creatinine level
3. Increased hematocrit
4. Increased blood urea nitrogen (BUN) level
The correct answer is "decreased serum sodium level". Syndrome of inappropriate antidiuretic hormone or SIADH is a disorder of the posterior pituitary gland wherein there is an abnormal increase in the secretion of antidiuretic hormone. As a result, there will be a decrease in water secretion in the renal distal tubules. Eventually, this will lead to a decrease in serum sodium level as a result of dilution.
