Acute hypernatremia dampens stress-induced enhancement of long-term potentiation in the dentate gyrus of rat hippocampus.

Stress often occurs within the context of homeostatic threat, requiring integration of physiological and psychological demands to trigger appropriate behavioral, autonomic and endocrine responses. However, the neural mechanism underlying stress integration remains elusive. Using an acute hypernatremic challenge (2.0M NaCl subcutaneous), we assessed whether physical state may affect subsequent responsiveness to psychogenic stressors. We found that experienced forced swimming (FS, 15min in 25°C), a model of psychogenic stress, enhanced long-term potentiation (LTP) induction in the dentate gyrus (DG) of the rat hippocampus ex vivo. The effect of FS on LTP was prevented when the animals were adrenalectomized or given mineralocorticoid receptor antagonist RU28318 before experiencing stress. Intriguingly, relative to normonatremic controls, hypernatremic challenge effectively elevated plasma sodium concentration and dampened FS-induced enhancement of LTP, which was prevented by adrenalectomy. In addition, acute hypernatremic challenge resulted in increased extracellular signal-regulated kinase (ERK)1/2 phosphorylation in the DG and occluded the subsequent activation of ERK1/2 by FS. Moreover, stress response dampening effects by acute hypernatremic challenge remained intact in conditional oxytocin receptor knockout mice. These results suggest that acute hypernatremic challenge evokes a sustained increase in plasma corticosterone concentration, which in turn produces stress-like changes in the DG, thereby occluding subsequent responsiveness to psychogenetic stress. They also fit into the general concept of "metaplasticity" - that is, the responsiveness to stress is not fixed but appears to be governed by the recent history of prior physical state.

The management of patients presenting with hypernatraemia: is aggressive management appropriate?

Hypernatraemia is a common finding among patients presenting to hospital. The aim of this observational study was to discover what types of patients presented with hypernatraemia and whether they were appropriately managed. The management of hypernatraemia was audited against common standards of care. Hypernatraemia at presentation carries a poor prognosis and in this study management of hypernatraemia was found to be done poorly, possibly because for many patients aggressive management was deemed inappropriate. The majority of patients who present with hypernatraemia are older, dependent and/or suffer from cognitive impairment. Many of these patients do not have a reversible cause for their hypernatraemia. These patients need to be recognised, ideally in the community, so that inappropriate admission can be avoided, but also on presentation to hospital so that appropriate care, which may be end-of-life care, can be provided.

Behavioural induced severe hypernatremia without neurological manifestations.

Hypernatremia is a relatively common entity and is more prevalent among the elderly and critically ill. A number of medical conditions are commonly associated with hypernatremia, and these differ substantially among children and adults. Severe hypernatremia is usually associated with central nervous system manifestations and carries a high mortality rate. We report a case of a female patient who presented to the emergency department of the King Khalid University Hospital, Riyadh, Saudi Arabia with severe hypernatremia and without any associated co-morbid conditions or neurological manifestations. We did not find any etiological background despite extensive evaluation other than under hydration due to decreased fluid intake, which was secondary to behavioural causes.

Maternal psychosocial aspects in hypernatremic dehydration with high sodium concentrations in breast milk: a case-control study.

OBJECTIVE: To investigate whether mothers, with no known biological reason to account for elevated breast milk sodium (BMS) and associated hypernatremic dehydration (HND) in their exclusively breastfed infants, have more adverse psychosocial characteristics compared with controls. METHODS: Design is prospective case-control. Mothers of 21 term infants diagnosed as HND with associated high BMS and mothers of 43 healthy, exclusively breastfed term infants, with expected milk sodium levels, were compared on rates of socio-demographic and relationship variables, pregnancy wantedness and planning, maternal attitudes towards breastfeeding, postnatal maternal depression and anxiety. A semi-structured interview, State and Trait Anxiety Inventory and Edinburgh Postnatal Depression Scale were used. RESULTS: Reported maternal history of previous psychiatric morbidity (57.1% vs. 18.6%; P = 0.003), poor relationship with her own mother (36.8% vs. 9.6%; P = 0.026), not finding herself suitable to be a mother (28.6% vs. 4.6%; P = 0.012), unplanned pregnancy (52.4% vs. 20.9%; P = 0.020) and higher state anxiety scores (mean (SD) = 42.2 (11.1) vs. 35.5 (10.5); P = 0.038) in the post-partum period were significantly common in mothers with elevated BMS levels compared with the controls. Univariate analyses revealed that unplanned pregnancy and maternal perception of not being suitable to be mother constitute significant risks with odds ratios 4.2 and 8.2, respectively. CONCLUSION: The present study displays that mothers, with no known biological reason to account for elevated BMS, have more adverse psychosocial characteristics compared with controls; emphasising the importance of psychosocial and emotional factors during lactation and offering implications for the establishment of successful lactation through providing additional psychosocial support to vulnerable mothers.

[Water electrolyte disorders in the postoperative clinical picture of basal-diencephalitic tumors]. / Vodno-élektrolitnye narusheniia v klinike posleoperatsionnogo perioda pri opukholiakh bazal'no-diéntsefal'noí lokalizatsii.

The paper deals with the relationship of homeostatic and motivational disorders in the postoperative clinical picture in basal-diencephalic tumors. The material included 354 clinical observations of: hypophysial adenoma (n = 135); craniopharyngioma (n = 71); tumors of the third ventricle (n = 88); basal meningiomas (n = 60). A comparative analysis of the findings allowed the authors to support that there are typical variants of changes in the patients' status, which reflect the nature of ion-osmotic disorders. The most significant mental disorders were transient hyperosmolar-hypernatriemic disturbances. The poor predictors were persistent hypernatriemia concurrent with evolving coma, systemic hemodynamic and respiratory disorders. Hyponatriemia is a better predictor of ionosmotic disorders, which requires a careful postoperative monitoring and a comparison of its findings with the specific features of intensive care performed.

Psychogenic adipsia in a patient with psychotic depression.

Psychogenic adipsia is exceedingly uncommon. We report a case of severe hypernatremia secondary to adipsia from psychotic depression. The patient regained appropriate thirst, drinking behavior, and water balance after electroconvulsant therapy.

Severe hypernatremia caused by age, isolation, and obstructive uropathy.

Although this is an extremely interesting case report from a medical viewpoint, inasmuch as it presents an unusual cause of hypernatremia, it is probably even more important because of its sociologic implications. The basic underlying causes are common in the aged, and as the number of senior and ultimately senior senior citizens increases, a repetition of the events enumerated here can be predicted in increasing numbers of patients.