Characteristic feature of the urine in diabetes insipidus include the following EXCEPT

Ans. c (Specific gravity > 1.020). (Ref. Harrison, Medicine, 18th. Ch. 340 and 44)Fluid deprivation test: If fluid deprivation does not result in urine concentration (osmolarity >300 mosmol/L, specific gravity >1.010) before body weight decreases by 5% or plasma osmolarity/sodium rise above the upper limit of normal, the patient has severe pituitary or severe nephrogenic DI. These disorders usually can be distinguished by administering desmopressin (0.03 g/kg SC or IV) and repeating the measurement of urine osmolarity 1-2 hours later. An increase of >50% indicates severe pituitary DI, whereas a smaller or absent response is strongly suggestive of nephrogenic DI.Criteria for Dl (Diabetes insipidus)# Polyuria of > 3 L/d# Urine osmolality < 3000 mOsm/kg# Urine specific gravity < 1.00.Criteria for central Dl# Inappropriately dilute urine even with strong stimuli for AVP secretion.# Absence of intrinsic renal disease.# Rise in urine osmolality with ADH.Criteria for nephrogenic Dl# Normal rates of renal filtration and solute excretion.# Persistent hypotonic urine.# Failure of exogenous ADH to raise urine osmolality or to reduce urine volume. Source: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JL, Loscalzo J: Harrison's principles of Internal Medicine, 18th Edition: www. accessmedicine. ComCopyrightr (S) The McGraw-Hill Companies, Inc. All rights reserved.