In a patient if administration of vasopressin does not increase the osmolality of urine, it indicates?: (A) ADH deficieny, (B) Renal hyposensitivity towards ADH, (C) SIADH, (D) Psychogenic polydipsia
Answer is B. Renal hyposensitivity towards ADH REF: Harrison's 17th ed p. 274 If the osmolality of urine increases after administration of ADH - Nephrogenic DI (Renal hyposensitivity) If the osmolality of urine decreases after administration of ADH- Central DI