Please use this identifier to cite or link to this item:
Title: Disturbed fluid and electrolyte homoeostasis following dehydration in elderly people.
Austin Authors: Phillips, P A;Johnston, Colin I;Gray, L
Affiliation: Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia
Issue Date: 1-Jan-1993
Publication information: Age and Ageing; 22(1): S26-33
Abstract: Disturbances in homoeostatic capacity are typical of the ageing process. Changes in the neuroendocrine controls of salt and water homoeostasis with age make elderly people more susceptible to fluid and electrolyte disturbances such as dehydration and overhydration. Not only do elderly subjects show reduced thirst and water intake following dehydration, but their kidneys are less able to retain water. This reduced thirst and water intake is not dependent on palatability of the liquids offered as the amounts drunk are no different if water alone or a variety of beverages are offered to healthy elderly dehydrated men. It is of interest that the arginine vasopressin (AVP) response to dehydration is maintained in elderly subjects, indicating that their reduced renal water retentive capacity is due to relative renal resistance to vasopressin. The mechanism underlying the reduced thirst is unclear. Dehydration causes plasma hypertonicity and reduced extracellular fluid (ECF) volume, both of which stimulate thirst and AVP secretion. Elderly subjects show deficits in sensing the reduced ECF volume through reduced low and high pressure baroreceptor sensitivity. In contrast, while the AVP responses to hypertonicity are maintained, the thirst responses seem to be reduced. It seems unlikely that the primary sensing 'osmoreceptor' neurons in the hypothalamus leading to AVP secretion or thirst would be differentially affected by age. Therefore the thirst deficit may result from changes with age in the more poorly defined pathways that bring thirst to consciousness. Following rehydration, thirst and AVP secretion are inhibited in young individuals thus avoiding overhydration.(ABSTRACT TRUNCATED AT 250 WORDS)
Gov't Doc #: 8438652
Journal: Age and Ageing
Type: Journal Article
Subjects: Aged
Arginine Vasopressin.physiology
Neurosecretory Systems.physiopathology
Water-Electrolyte Balance.physiology
Appears in Collections:Journal articles

Show full item record

Page view(s)

checked on Apr 19, 2024

Google ScholarTM


Items in AHRO are protected by copyright, with all rights reserved, unless otherwise indicated.