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Hyponatraemia in older people as a sign of adrenal insufficiency: a case–control study
Author(s) -
Winchester Behr T.,
Sonnenblick M.,
Nesher G.,
Munter G.
Publication year - 2012
Publication title -
internal medicine journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.596
H-Index - 70
eISSN - 1445-5994
pISSN - 1444-0903
DOI - 10.1111/j.1445-5994.2010.02306.x
Subject(s) - medicine , adrenal insufficiency , basal (medicine) , hyponatremia , endocrinology , glucocorticoid , hormone , hydrocortisone , stimulation , adrenocorticotropic hormone , insulin
Background: Hyponatraemia is a common cause of hospitalisation in older adults. Adrenal insufficiency (AI) can result in hyponatraemia. Aim: The aim of our study was to determine the frequency and characteristics of AI in elderly patients with hyponatraemia. Methods: Thirty patients ≥65 years with Na + ≤130 mmol/L and 30 age‐matched control subjects, all hospitalised, were included in the study. Plasma cortisol levels were determined before and after intravenous administration of 1 µg synthetic adrenocorticotropin hormone. A peak cortisol >550 nmol/L was considered to exclude AI. Results: Sodium levels were 125 ± 5 and 139.8 ± 2 mmol/L in the hyponatremic and control groups respectively. Baseline cortisol <550 nmol/L was found in a half of hyponatremic patients. However, stimulated cortisol levels were compatible with AI in only one case (3%) and none of the controls. The mean cortisol levels were significantly higher in hyponatremic compared with control subjects, both in the basal state (585 ± 215 and 381 ± 135 nmol/L, respectively, P < 0.001) and after stimulation (933 ± 254 and 781 ± 160 nmol/L, P < 0.05). However, the incremental increase in cortisol levels after stimulation was similar in the two groups (361 ± 196 and 403 ± 155 nmol/L) Conclusions: AI is an uncommon cause of hyponatraemia in older age. Based on this small cohort, AI may be present in 3% of elderly patients with hyponatraemia. AI cannot be excluded by baseline cortisol in a significant minority of hyponatremic patients and further testing with adrenocorticotropin hormone stimulation is needed.