title: Nephrotic syndrome complicated by idiopathic central diabetes insipidus.
abstract: BACKGROUND
  There is ongoing discussion regarding the mechanisms underlying edema formation in nephrotic syndrome (NS). Many studies published in the last decade reported that primary renal sodium retention was a major factor in edema formation. However, many of the factors influencing edema formation in NS remain unclear, including the role of arginine vasopressin (AVP).
  
  
  METHODS
  We report a 12-year-old boy with steroid-dependent NS complicated by idiopathic central diabetes insipidus (CDI). He did not develop edema during his first relapse of NS after developing CDI, despite having hypoalbuminemia. He had polydipsia, polyuria, low urine osmolality, and a low serum arginine AVP level. His fractional excretion of sodium was only slightly low. Endocrinological testing and magnetic resonance imaging revealed idiopathic CDI. After starting desmopressin therapy, he developed edema when his NS relapsed.
  
  
  CONCLUSIONS
  This is the first known reported case of NS in a patient with CDI. The findings suggest that appropriate AVP secretion in response to an increase in serum osmolality caused by renal sodium retention is necessary for excess extracellular fluid accumulation in NS. Further investigation is needed to more fully understand the role of AVP in edema formation in NS.
authors.affiliation: Faculty of Medicine, Division of Pediatrics, Department of Reproductive and Developmental Medicine, University of Miyazaki, 5200 Kihara, Kiyokake-cho, Miyazaki, 889-1692, Japan, ktakao@fc.miyazaki-u.ac.jp.
authors.forename: Takao
authors.initials: T
authors.lastname: Konomoto
authors.forename: Etsuko
authors.initials: E
authors.lastname: Tanaka
authors.forename: Hideaki
authors.initials: H
authors.lastname: Imamura
authors.forename: Mayuko
authors.initials: M
authors.lastname: Orita
authors.forename: Hirotake
authors.initials: H
authors.lastname: Sawada
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nunoi
mesh_terms: D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001127:Arginine Vasopressin / Q000097:blood; D002648:Child; D003894:Deamino Arginine Vasopressin / Q000627:therapeutic use; D020790:Diabetes Insipidus, Neurogenic / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D004487:Edema / Q000209:etiology; D006801:Humans; D008297:Male; D009404:Nephrotic Syndrome / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D011239:Prednisolone / Q000627:therapeutic use; D014868:Water Deprivation
chemical_list: D000893:Anti-Inflammatory Agents; D001127:Arginine Vasopressin; D011239:Prednisolone; D003894:Deamino Arginine Vasopressin