<prompt> Characteristic feature of the urine in diabetes insipidus include the following EXCEPTHas no proteinsHas no sugarSpecific gravity 1.020No casts  <response>: Ans. c Specific gravity 1.020. Ref. Harrison, Medicine, 18th. Ch. 340 and 44Fluid deprivation test: If fluid deprivation does not result in urine concentration osmolarity 300 mosmolL, specific gravity 1.010 before body weight decreases by 5 or plasma osmolaritysodium 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 gkg 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 Ld Urine osmolality 3000 mOsmkg 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: Harrisons principles of Internal Medicine, 18th Edition: www. accessmedicine. ComCopyrightr S The McGraw-Hill Companies, Inc. All rights reserved. 