Which statement correctly differentiates nephrogenic diabetes insipidus from central diabetes insipidus?

Which statement correctly differentiates nephrogenic diabetes insipidus from central diabetes insipidus?

• A. It Responds to ADH Replacement, While Central DI Does Not
• B. It Does Not Respond to ADH
• C. It Presents with Polyphagia
• D. It Causes Hyponatremia

Answer: (B)

The key idea is how the body responds to antidiuretic hormone. In central diabetes insipidus, there is a deficit of ADH, so giving ADH (desmopressin) lowers urine output and concentrates urine. In nephrogenic diabetes insipidus, the kidneys are insensitive to ADH, so administering ADH does not improve the ability to concentrate urine; polyuria and dilute urine persist. Therefore, the statement that nephrogenic diabetes insipidus does not respond to ADH is the differentiating feature. The other options don’t fit because releasing ADH helps central DI but not nephrogenic DI; polyphagia isn’t a characteristic of DI (it’s more about appetite in other conditions); and hyponatremia is not typical of DI, which more often leads to hypernatremia with dehydration if not matched by fluid intake.

The key idea is how the body responds to antidiuretic hormone. In central diabetes insipidus, there is a deficit of ADH, so giving ADH (desmopressin) lowers urine output and concentrates urine. In nephrogenic diabetes insipidus, the kidneys are insensitive to ADH, so administering ADH does not improve the ability to concentrate urine; polyuria and dilute urine persist. Therefore, the statement that nephrogenic diabetes insipidus does not respond to ADH is the differentiating feature.

The other options don’t fit because releasing ADH helps central DI but not nephrogenic DI; polyphagia isn’t a characteristic of DI (it’s more about appetite in other conditions); and hyponatremia is not typical of DI, which more often leads to hypernatremia with dehydration if not matched by fluid intake.