Beyond semantics: defining hyponatremia in secondary adrenal insufficiency

[Features of water-electrolyte balance in persons of the older age group]

Age-related changes have a great influence on the regulation of water and electrolyte homeostasis in the body, which is regulated by a complex interaction of environmental factors, drinking behavior, the secretion of a number of hormones and hormone-like substances, as well as the innervation and functional state of the kidneys. It is well known that the changes that are part of physiological aging underlie fluid and electrolyte imbalances, exacerbated by the presence of age-related diseases, medications, or a number of external factors such as malnutrition, fluid intake, and the presence of dementia. This review considers literature data on the effect of normal aging on the development of pathology of the water-sodium balance, including dehydration of senile patients, hyponatremia, hypernatremia, changes in the secretion of antidiuretic hormone and the activity of elements of the renin-angiotensin-aldosterone system.

Impact of etiology, age and gender on onset and severity of hyponatremia in patients with hypopituitarism: retrospective analysis in a specialised endocrine unit

BACKGROUND

Hyponatremia can unmask hypopituitarism and secondary adrenal insufficiency. This is important, since the need to screen for steroid deficiency, in patients with hyponatremia is often neglected.

PATIENTS AND METHODS

In a retrospective study, twenty-five patients (13f/12m, age 58.9 ± 18.6 years) with hyponatremia (119.7 ± 10.5 mmol/L) were identified among 260 in-patients treated for hypopituitarism in our specialized endocrine unit, over the last decade. We analyzed clinical characteristics, etiology, and severity of hypopituitarism in patients who presented with hyponatremia.

RESULTS

Hyponatremia was recorded in 9.6% of our patients with hypopituitarism. In 80.7% it was the key to diagnosis of hypopituitarism. All patients with hyponatremia were steroid deficient with complete hypopituitarism compared to 75% (steroid deficient) and 60% (complete hypopituitarism) of the patients in the cohort. The most common etiology of hypopituitarism was non-functioning pituitary macro adenoma (NFPA) (n = 128, 49.2%). Patients with hyponatremia were divided into two groups, based on the etiology of hypopituitarism: Group 1. with NFPA n = 15 (5F/10M), mean age 71.47 ± 4.8 years, who were significantly older compared to patients with hyponatremia from other rare causes of hypopituitarism in Group 2. n = 10 (8F/2M), mean age 40.2 ± 15.3 years (p < 0.01), such as: congenital hypopituitarism(n = 2), Sheehan's syndrome (n = 2), intracranial aneurysm (n = 2), lymphocytic hypophysitis (n = 1), traumatic brain injury (n = 1), surgery and radiotherapy for astrocytoma (n = 1), pituitary metastasis from bronchial carcinoma (n = 1). Hyponatremia was more severe in Group 2. compared to Group 1. (113.5 ± 10.9 mmol/L vs. 124.3 ± 8.1 mmol/L, p < 0.01). Older age (p = 0.0001) and number of endocrine deficiencies (p < 0.05) were identified as predictive factors for hyponatremia by multivariate analysis in patients with hypopituitarism.

CONCLUSION

Hyponatremia is an important presenting feature of pituitary disease and a strong indicator of life-threatening steroid deficiency. Old age and severity of hypopituitarism are major risk factors for hyponatremia. In older patients NFPA is the most common etiology, while other rare causes of hypopituitarism are more prevalent in younger patients with hyponatremia.

Clinical aspects of changes in water and sodium homeostasis in the elderly

The population of elderly individuals is increasing worldwide. With aging, various hormonal and kidney changes occur, both affecting water homeostasis. Aging is a risk factor for chronic kidney disease (CKD) and many features of CKD are reproduced in the aging kidney. Dehydration and hyperosmolarity can be triggered by diminished thirst perception in this population. Elderly with dementia are especially susceptible to abnormalities of their electrolyte and body water homeostasis and should be (re-)assessed for polypharmacy. Hypo- and hypernatremia can be life threatening and should be diagnosed and treated promptly, following current practice guidelines. In severe cases of acute symptomatic hyponatremia, a rapid bolus of 100 to 150 ml of intravenous 3% hypertonic saline is appropriate to avert catastrophic outcomes; for asymptomatic hyponatremia, a very gradual correction is preferred. In summary, the body sodium (Na+) balance is regulated by a complex interplay of environmental and individual factors. In this review, we attempt to provide an overview on this topic, including dehydration, hyponatremia, hypernatremia, age-related kidney changes, water and sodium balance, and age-related changes in the vasopressin and renin-angiotensin-aldosterone system.

Challenges in the acute management of profound hyponatremia presenting with severe symptoms

Currently available guidelines in the acute management of severely symptomatic hypotonic hyponatremia vary in their approach to the use of hypertonic saline. In the acute setting, deciding on when to implement available treatment algorithm using hypertonic saline may be difficult, given that the duration of hyponatremia and potential alternative diagnoses presenting with similar symptoms may be hard to establish promptly. We present the case of a young female with symptomatic profound hyponatremia who subsequently developed osmotic demyelination syndrome due to rapid overcorrection of serum sodium concentration. We discuss the interplay between the dynamic pathophysiological processes responsible for hypotonic hyponatremia in adrenal insufficiency and conduct a detailed analysis of currently available guidelines to highlight the challenges in acute and reactive treatment in clinical practice.

Clinical practice guideline on diagnosis and treatment of hyponatraemia

Hyponatraemia, defined as a serum sodium concentration <135 mmol/l, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice. It can lead to a wide spectrum of clinical symptoms, from subtle to severe or even life threatening, and is associated with increased mortality, morbidity and length of hospital stay in patients presenting with a range of conditions. Despite this, the management of patients remains problematic. The prevalence of hyponatraemia in widely different conditions and the fact that hyponatraemia is managed by clinicians with a broad variety of backgrounds have fostered diverse institution- and speciality-based approaches to diagnosis and treatment. To obtain a common and holistic view, the European Society of Intensive Care Medicine (ESICM), the European Society of Endocrinology (ESE) and the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA), represented by European Renal Best Practice (ERBP), have developed the Clinical Practice Guideline on the diagnostic approach and treatment of hyponatraemia as a joint venture of three societies representing specialists with a natural interest in hyponatraemia. In addition to a rigorous approach to methodology and evaluation, we were keen to ensure that the document focused on patient-important outcomes and included utility for clinicians involved in everyday practice.

Clinical practice guideline on diagnosis and treatment of hyponatraemia

Hyponatraemia, defined as a serum sodium concentration <135 mmol/l, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice. It can lead to a wide spectrum of clinical symptoms, from subtle to severe or even life threatening, and is associated with increased mortality, morbidity and length of hospital stay in patients presenting with a range of conditions. Despite this, the management of patients remains problematic. The prevalence of hyponatraemia in widely different conditions and the fact that hyponatraemia is managed by clinicians with a broad variety of backgrounds have fostered diverse institution- and speciality-based approaches to diagnosis and treatment. To obtain a common and holistic view, the European Society of Intensive Care Medicine (ESICM), the European Society of Endocrinology (ESE) and the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA), represented by European Renal Best Practice (ERBP), have developed the Clinical Practice Guideline on the diagnostic approach and treatment of hyponatraemia as a joint venture of three societies representing specialists with a natural interest in hyponatraemia. In addition to a rigorous approach to methodology and evaluation, we were keen to ensure that the document focused on patient-important outcomes and included utility for clinicians involved in everyday practice.

Hyponatremia is the valuable manifestation for initiating diagnosis of hypopituitarism in elderly

The present study was undertaken to determine clinical features of hypopituitarism in elderly subjects. Thirty-one elderly patients with hypopituitarism were enrolled. They were 19 males and 12 females, with the ages of 70.7±5.4 years ranging from 62 to 80 years. High prevalence of hyponatremia (80.6%) and hypoglycemia (29.0%) was found, and it was totally different from that in hypopituitarism from general population. There were two groups of hyponatremia derived from their clinical courses, namely, acute deterioration of hyponatremia and chronically persistent hyponatremia. Analysis for deficient hormones clearly showed that ACTH deficiency was highly found in 30 of 31 patients. There was no difference in serum cortisol levels between the hyponatremic and normonatremic patients. Despite hypoosmolality, plasma arginine vasopressin (AVP) was apparently high in the hyponatremic patients compared with in the normonatremic ones. The present study indicates that hyponatremia is the valuable finding for initiating diagnosis of hypopituitarism, and that augmented release of AVP may be involved in developing hyponatremia in elderly patients with hypopituitarism.

Severe hyponatremia due to ACTH insufficiency in a 14 year-old girl with growth hormone deficiency

SIADH-like hyponatremia as the presenting manifestation of ACTH deficiency is rare in childhood. Here we report a 14 year-old girl who, after 8 years of GH replacement and subsequent treatment for subclinical secondary hypothyroidism, presented with confusion and disorientation due to severe hyponatremia. When her pituitary axis was re-assessed, she was diagnosed as having ACTH deficiency associated with multiple pituitary hormone deficiencies (MPHD) (including GH, FSH, LH, and subclinical TSH deficiencies). She responded poorly to treatment with only hypertonic fluid, but improved after addition of hydrocortisone replacement. The purpose of this paper is to emphasize the importance of suspecting ACTH insufficiency in children with GH deficiency if hyponatremia develops.

Hypopituitarism in the elderly: two case-reports with heterogeneous presentation

Hypopituitarism (HYPO) is an under-investigated disease in older patients. Symptoms, which may be life-threatening, are aspecific and often attributed to aging and/or related morbidities. We describe here the cases of two elderly patients who were ultimately diagnosed as having HYPO, the clinical presentations and etiologies of which were different. In the first patient, an invasive non-secreting pituitary macroadenoma causing HYPO was detected on brain morphological evaluation for head trauma secondary to falling. Glucocorticoid replacement therapy was started. Thyroid function evaluation showed hyperthyroidism (due to a known toxic multinodular goiter), which was already on treatment with methimazole; ultimately, after withdrawal of the antithyroid drug, secondary hypothyroidism occurred. The patient underwent non-radical pituitary surgery. Cognitive function, gait impairment and falling, which had previously been attributed only to aging, improved markedly after cortisone acetate and L-thyroxine replacement therapy. The second patient was hospitalized one month after the onset of hypotension, edema and pain in the legs, and progressive psychomotor impairment, which ultimately resulted in an intermittent soporous state. She was diagnosed as having global anterior HYPO secondary to empty sella, which caused severe multifaceted clinical and biochemical abnormalities (hyponatremia, pancytopenia, rhabdomyolysis). After treatment with i.v. fluids and hydrocortisone, the patient's clinical condition and biochemical alterations improved, and normalized over time with oral cortisone acetate and Lthyroxine combination therapy. Several protean symptoms that impair the quality of life of elderly patients are usually ascribed to aging. Such symptoms should be investigated with regard to possible HYPO, treatment of which can result in significant clinical benefit.