Severe Hypernatremia with Impaired Thirst

Glycerol kinase deficiency presenting with hypodipsia, osmotic diuresis and severe hypernatraemia

“…This unique feature explains why hypernatraemic dehydration has never been observed in other cases of GKD. Many, but not all, reported cases of hypodipsic hypernatraemia had organic lesions in the pituitary gland or hypothalamus region (Perez et al 1989). There was no structural abnormality demonstrable by MRI in our case.…”

“…Water intake prevents the development of hypernatraemia (Perez et al 1989). Consequently, hypernatraemia almost never develops in a conscious person unless thirst is deficient or water intake is impaired for other reasons (Perez et al 1989). Our patient had an attenuated thirst sensation, which arrested the protective mechanism guarding against the development of hypernatraemia.…”

“…Hyperosmolality is a strong stimulus of the thirst sensation. Water intake prevents the development of hypernatraemia (Perez et al 1989). Consequently, hypernatraemia almost never develops in a conscious person unless thirst is deficient or water intake is impaired for other reasons (Perez et al 1989).…”

Hypothalamic adipic hypernatraemia syndrome with normal osmoregulation of vasopressin

“…1 Plasma and urine osmolality, urine amount and plasma ADH response to dextrose load and hypertonic saline infusion chronic hypernatraemia due to adipsia. Three types of adipsic hypernatraemia syndrome have been described [15]: (1) normal osmoregulation of AVP, (2) a partial defect in AVP secretion, and (3) a total defect in osmoregulation of AVP. The first type is extremely rare and only a few cases have been reported in the literature [1,8].…”

“…The osmoreceptors are extremely sensitive, responding to minimal alterations in the osmolality. In humans, the osmotic threshold for ADH release is about 280 to 290 mosm/kg and the osmotic threshold for thirst has been reported to be between 2 to 10 mosmol/kg higher [15].…”