title: A patient with partial central diabetes insipidus: clarifying pathophysiology and designing treatment.
abstract: Studies were undertaken in a 32-year-old man who developed polyuria (4 L/d) a few days after a basal skull fracture; the condition persisted 1 year after the accident. The other major features were thirst, a plasma sodium of 143 mmol/L, 24-hour urine osmolality of 221 mOsm/kg H(2)O, and levels of vasopressin in plasma that were less than 0.5 pg/mL on 20 separate occasions. The 24-hour urine volume implied that the diagnosis was partial rather than complete central diabetes insipidus; however, several random urine samples had a much higher osmolality. An infusion of hypertonic saline led to the release of vasopressin and the excretion of concentrated urine. We propose that the basis for the lesion may be the transection of some, but not all, of the fibers connecting the osmostat and vasopressin release center. This partial transection could permit vasopressin to be secreted in response to a larger rise in plasma sodium concentration. This pathophysiologic analysis provided the basis for therapy to minimize the degree of polyuria.
authors.affiliation: Renal Divisions, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada. kamel.kamel@utoronto.ca
authors.forename: K S
authors.initials: KS
authors.lastname: Kamel
authors.forename: D G
authors.initials: DG
authors.lastname: Bichet
authors.forename: M L
authors.initials: ML
authors.lastname: Halperin
mesh_terms: D000328:Adult; D003919:Diabetes Insipidus / Q000503:physiopathology / Q000652:urine*; D006801:Humans; D008297:Male; D011141:Polyuria / Q000628:therapy*; D013894:Thirst