Clinical practice guideline on diagnosis and treatment of hyponatraemia

Evaluation and Management of Hyponatremia in Heart Failure

PURPOSE OF REVIEW

To provide a contemporary overview of the pathophysiology, evaluation, and treatment of hyponatremia in heart failure (HF).

RECENT FINDINGS

Potassium and magnesium losses due to poor nutritional intake and treatment with diuretics cause an intracellular sodium shift in HF that may contribute to hyponatremia. Impaired renal blood flow leading to a lower glomerular filtration rate and increased proximal tubular reabsorption lead to an impaired tubular flux through diluting distal segments of the nephron, compromising electrolyte-free water excretion. Hyponatremia in HF is typically a condition of impaired water excretion by the kidneys on a background of potassium and magnesium depletion. While those cations can and should be easily repleted, further treatment should mainly focus on improving the underlying HF and hemodynamics, while addressing congestion. For decongestive treatment, proximally acting diuretics such as sodium-glucose co-transporter-2 inhibitors, acetazolamide, and loop diuretics are the preferred options.

Mortality predictors of patients diagnosed with severe hyponatremia in the emergency department

PURPOSE

To determine the factors affecting mortality as a result of the analysis of the demographic and clinical characteristics and laboratory parameters of patients whose serum Na value was determined to be 125 mEq/L or below at the time of admission to the emergency department (ED).

METHOD

Patients over 18 years of age who admitted to the ED of a tertiary hospital between September 2021 and September 2022 and whose serum sodium level was determined to be 125 mEq/L and below were included in the study. Demographic and clinical characteristics, admission complaints, medications used, Charles comorbidity index (CCI), laboratory parameters, and outcomes of the patients included in the study were recorded in the data form.

RESULTS

Three hundred ninety-nine patients were included in the study. When the 30-day mortality of the patients is examined, the mortality rate was found to be 21.6%. In the analyses performed for the predictive power of laboratory parameters for mortality, it was determined that the highest predictive power among the predictive values determined by the area under the curve (AUC) was the albumin level (AUC 0.801, 95% CI 0.753-0.849, p < 0.001). In the binary logistic regression analysis, urea and albumin were independent predictors of 30-day mortality.

CONCLUSION

According to study data, albumin and urea levels are independent predictors of 30-day mortality in patients diagnosed with severe hyponatremia in the emergency department.

Case report: Secondary failure to tolvaptan in a patient with SCLC and paraneoplastic SIADH

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is frequent in lung cancer patients. Here, we report a case with persistent hyponatremia, which suggested malignant SIADH and facilitated an early diagnosis of small cell lung cancer (SCLC). A combined radio-chemotherapy led to a partial remission and resolution of SIADH. An early relapse was indicated by reoccurring severe hyponatremia and increased copeptin levels, which were used as surrogate markers for the antidiuretic hormone (ADH). As palliative immunochemotherapy, together with fluid restriction and solute substitution, were unable to control hyponatremia, treatment with the ADH V2-receptor antagonist tolvaptan was initiated. Over time, the dose of tolvaptan needed to be increased, paralleled by a well-documented exponential increase of copeptin levels. In summary and conclusion, this is a rare case of a secondary failure to tolvaptan with unique documentary evidence of increasing copeptin levels. This observation supports the hypothesis that exceedingly high ADH levels may lead to competitive displacement of tolvaptan from the V2 receptor.

Treatment of severe hyponatremia with continuous renal replacement therapy: A case and review of corrective strategies

Treatment of severely hyponatremic patients with continuous renal replacement therapy (CRRT) presents a unique challenge given the lack of commercial options for hypotonic replacement solutions or dialysate. We report the case of a 55-year-old male who presented with profound, symptomatic hyponatremia in the setting of acute kidney injury (AKI). The patient was found to have a serum sodium concentration of 97 mEq/L because of free water retention that occurred during severe AKI from viral gastroenteritis and rhabdomyolysis. Continuous veno-venous hemofiltration (CVVH) was required for AKI complicated by hyperkalemia, metabolic acidosis, and uremia. To prevent overcorrection of serum sodium, replacement fluids customized to natremic status had to be prepared. Conventional replacement fluid was modified on a daily basis to create hypotonic solutions with successively higher sodium concentrations. Over the course of a week, serum sodium successfully improved in a controlled and safe fashion. This case incorporates and reviews the variety of methods that have been used to safely manage severe hyponatremia with CRRT.

The syndrome of inappropriate antidiuretic hormone associated with nasal and paranasal malignant tumors

PURPOSE

To investigate the clinical characteristics of the syndrome of inappropriate antidiuretic hormone (SIADH) associated with nasal and paranasal malignant tumors.

METHODS

Patients with locally advanced or recurrence/metastatic malignant tumors of the nasal and paranasal sinuses were included. The SIADH was diagnosed according to the diagnostic criteria. The clinical characteristics of SIADH patients were retrospectively analyzed.

RESULTS

Six patients (6/188, 3.2%) met the diagnostic criteria of SIADH, including four olfactory neuroblastoma (4/26, 15.4%), one neuroendocrine carcinoma (1/9, 11.1%), and one squamous cell carcinoma (1/63, 1.6%). Five patients (83.3%) had severe hyponatremia; however, the hyponatremia could be improved by fluid restriction or tolvaptan. Three patients' SIADH were recovered during the chemotherapy and the other three were recovered after the surgery.

CONCLUSION

The incidence of SIADH associated with nasal and paranasal malignant tumors is relatively more common in olfactory neuroblastoma and neuroendocrine carcinoma. The hyponatremia caused by SIADH may be corrected by fluid restriction or tolvaptan, and the SIADH may be recovered through anti-tumor therapy.

Hyponatremia in the Context of Liver Disease

Hyponatremia is common in patients with liver disease and is associated with increased mortality, morbidity, and a reduced quality of life. In liver transplantation, the inclusion of hyponatremia in organ allocation scores has reduced waitlist mortality. Portal hypertension and the resulting lowering of the effective arterial blood volume are important pathogenetic factors, but in most patients with liver disease, hyponatremia is multifactorial. Treatment requires a multifaceted approach that tries to reduce electrolyte-free water intake, restore urinary dilution, and increase nonelectrolyte solute excretion. Albumin therapy for hyponatremia is a peculiarity of advanced liver disease. Its use appears to be increasing, while the vaptans are currently only given in selected cases. Osmotic demyelination is a special concern in patients with liver disease. Serial checks of serum sodium concentrations and urine volume monitoring are mandatory.

Initial dysnatremia and clinical outcomes in pediatric traumatic brain injury: a multicenter observational study

PURPOSE

We aimed to investigate the association between initial dysnatremia (hyponatremia and hypernatremia) and in-hospital mortality, as well as between initial dysnatremia and functional outcomes, among children with traumatic brain injury (TBI).

METHOD

We performed a multicenter observational study among 26 pediatric intensive care units from January 2014 to August 2022. We recruited children with TBI under 18 years of age who presented to participating sites within 24 h of injury. We compared demographics and clinical characteristics between children with initial hyponatremia and eu-natremia and between those with initial hypernatremia and eu-natremia. We defined poor functional outcome as a discharge Pediatric Cerebral Performance Category (PCPC) score of moderate, severe disability, coma, and death, or an increase of at least 2 categories from baseline. We performed multivariable logistic regression for mortality and poor PCPC outcome.

RESULTS

Among 648 children, 84 (13.0%) and 42 (6.5%) presented with hyponatremia and hypernatremia, respectively. We observed fewer 14-day ventilation-free days between those with initial hyponatremia [7.0 (interquartile range (IQR) = 0.0-11.0)] and initial hypernatremia [0.0 (IQR = 0.0-10.0)], compared to eu-natremia [9.0 (IQR = 4.0-12.0); p = 0.006 and p < 0.001]. We observed fewer 14-day ICU-free days between those with initial hyponatremia [3.0 (IQR = 0.0-9.0)] and initial hypernatremia [0.0 (IQR = 0.0-3.0)], compared to eu-natremia [7.0 (IQR = 0.0-11.0); p = 0.006 and p < 0.001]. After adjusting for age, severity, and sex, presenting hyponatremia was associated with in-hospital mortality [adjusted odds ratio (aOR) = 2.47, 95% confidence interval (CI) = 1.31-4.66, p = 0.005] and poor outcome (aOR = 1.67, 95% CI = 1.01-2.76, p = 0.045). After adjustment, initial hypernatremia was associated with mortality (aOR = 5.91, 95% CI = 2.85-12.25, p < 0.001) and poor outcome (aOR = 3.00, 95% CI = 1.50-5.98, p = 0.002).

CONCLUSION

Among children with TBI, presenting dysnatremia was associated with in-hospital mortality and poor functional outcome, particularly hypernatremia. Future research should investigate longitudinal sodium measurements in pediatric TBI and their association with clinical outcomes.

[Consensus recommendations on the diagnosis and treatment of hyponatremia from the Austrian Society for Nephrology 2024]

Hyponatremia is a disorder of water homeostasis. Water balance is maintained by the collaboration of renal function and cerebral structures, which regulate thirst mechanisms and secretion of the antidiuretic hormone. Measurement of serum-osmolality, urine osmolality and urine-sodium concentration help to diagnose the different reasons for hyponatremia. Hyponatremia induces cerebral edema and might lead to severe neurological symptoms, which need acute therapy. Also, mild forms of hyponatremia should be treated causally, or at least symptomatically. An inadequate fast increase of the serum sodium level should be avoided, because it raises the risk of cerebral osmotic demyelination. Basic pathophysiological knowledge is necessary to identify the different reasons for hyponatremia which need different therapeutic procedures.

Osmotic demyelination as a complication of hyponatremia correction: a systematic review

BACKGROUND

Rapid correction of hyponatremia, especially when severe and chronic, can result in osmotic demyelination. The latest guideline for diagnosis and treatment of hyponatremia (2014) recommends a correction limit of 10 mEq/L/day. Our aim was to summarize published cases of osmotic demyelination to assess the adequacy of this recommendation.

METHOD

Systematic review of case reports of osmotic demyelination. We included cases confirmed by imaging or pathology exam, in people over 18 years of age, published between 1997 and 2019, in English or Portuguese.

RESULTS

We evaluated 96 cases of osmotic demyelination, 58.3% female, with a mean age of 48.2 ± 12.9 years. Median admission serum sodium was 105 mEq/L and > 90% of patients had severe hyponatremia (<120 mEq/L). Reports of gastrointestinal tract disorders (38.5%), alcoholism (31.3%) and use of diuretics (27%) were common. Correction of hyponatremia was performed mainly with isotonic (46.9%) or hypertonic (33.7%) saline solution. Correction of associated hypokalemia occurred in 18.8%. In 66.6% of cases there was correction of natremia above 10 mEq/L on the first day of hospitalization; the rate was not reported in 22.9% and in only 10.4% was it less than 10 mEq/L/day.

CONCLUSION

The development of osmotic demyelination was predominant in women under 50 years of age, with severe hyponatremia and rapid correction. In 10.4% of cases, there was demyelination even with correction <10 mEq/L/day. These data reinforce the need for conservative targets for high-risk patients, such as 4-6 mEq/L/day, not exceeding the limit of 8 mEq/L/day.

Classifying Hypotonic Hyponatremia by Projected Treatment Effects - A Quantitative 3-Dimensional Framework

Introduction

The diagnostic algorithms currently used for hypotonic hyponatremia focus primarily on impaired urinary dilution and often neglect the influence of free water intake and solute excretion. We hypothesized that, in each case of hypotonic hyponatremia different pathophysiological mechanisms play a role simultaneously.

Methods

Using clinical data of the previous observational Co-Med study, we defined each case of hypotonic hyponatremia concurrently in 3 dimensions as follows: (i) high net free water intake (HNFWI), (ii) impaired dilution of the urine (IDU), and (iii) low nonelectrolyte solute excretion (LNESE). For each dimension, a "standard delta sodium" (sdna) was calculated reflecting the expected difference to the serum sodium concentration, that would result from changing a dimension to a specific and equivalent target level.

Results

Results from 279 patients were used for this analysis. With target levels of free water intake and urine osmolality at the fifth percentile, and nonelectrolyte solute excretion at the 95th percentile, median (interquartile range) sdna values were 7.1 (4.8-10.2) for HNFWI, 11.8 (7.0-18.6) for IDU and 2.6 (1.6-4.2) mmol/l per 24 hours for LNESE. Sdna results in individual patients were highest with IDU in 68.5%, HNFWI in 30.8% and 0.7% with LNESE. At an sdna-level of at least 4mmol/l per 24 hours, the prevalence of HNFWI was 78.9%, IDU 87.1%, and LNESE 26.5%. 77.5% of patients had 2 or all 3 mechanisms present. Hyponatremia was mostly multifactorial in subgroups according to classic categories of hyponatremia and typical comorbidities as well.

Conclusion

Hypotonic hyponatremia can be quantitatively defined by 3 dimensions. Most cases should be considered multifactorial.

Choice of creep or maintenance fluid type and their impact on total daily ICU sodium burden in critically ill patients: A systematic review and meta-analysis

PURPOSE

Maintenance and hidden/creep fluids are a major source of fluid and sodium intake in intensive care unit (ICU) patients. Recent research indicates that low versus high sodium content maintenance fluids could decrease fluid and sodium burden. We conducted a systematic review (SR) with meta-analysis to summarize the impact of maintenance fluid choice on total daily sodium in ICU patients.

MATERIALS AND METHODS

Systematic literature search in Pubmed, Embase, the Cochrane Library and the.

CLINICAL TRIALS REGISTRY

Only controlled clinical trials were included.

EXCLUSION CRITERIA

trials on resuscitation fluids, performed in the emergency department only and in pediatric patients. Primary objective was the reduction in mean total sodium intake with low versus high sodium content maintenance/creep fluids.

RESULTS

Five studies (1105 patients) were included. Heterogeneity was high.Risk of bias was moderate. Mean daily sodium reduction was 117 mmol (95%Confidence Interval [CI] -174; -59; p < 0.001) with low versus high sodium content maintenance/creep fluids. Incidence of hyperchloremia was lower (OR 0.26; 95%CI 0.1; 0.64) with low sodium. There were no differences in the incidences of hyper-/hyponatremia and fluid balances.

CONCLUSION

Using low sodium content maintenance/creep fluids substantially reduces daily sodium burden in adult ICU patients. Significant knowledge/research gaps exist regarding relevance and safety.

TRIAL REGISTRATION

PROSPERO 2022 CRD42022300577 (February 2022).

Epidemiology and predictors of hyponatremia in a contemporary cohort of patients with malignancy: a retrospective cohort study

Background

Hyponatremia is associated with worse outcomes among patients with malignancy. However, contemporary cohort data on epidemiology and risk factors are lacking.

Methods

In this single-centre, retrospective cohort study, patients who received intravenous antineoplastic agents from 2018 to 2020 at Nagoya City University Hospital were enrolled. Associations of demographics, antineoplastic agents, types of malignancy and concomitant medications with hyponatremia, defined as serum sodium concentration ≤130 mmol/l, were analysed by mixed-effects logistic regression and the machine learning-based LightGBM model artificial intelligence technology.

Results

Among 2644 patients, 657 (24.8%) developed at least one episode of hyponatremia. Approximately 80% of hyponatremia was due to sodium wasting from the kidneys. Variables associated with hyponatremia both by mixed-effects logistic regression and the LightGBM model were older age, hypoalbuminemia and higher estimated glomerular filtration rate. Among antineoplastic agents, cisplatin {odds ratio [OR] 1.52 [95% confidence interval (CI) 1.18-1.96]}, pembrolizumab [OR 1.42 (95% CI 1.02-1.97)] and bortezomib [OR 3.04 (95% CI 1.96-4.71)] were associated with hyponatremia and these variables also had a positive impact on predicted hyponatremia in the LightGBM model.

Conclusions

Hyponatremia was common among patients with malignancy. In addition to older age and poor nutritional status, novel antineoplastic agents, including immune checkpoint inhibitors and bortezomib, should be recognized as risk factors for hyponatremia.

Disorders of Sodium

Sodium imbalances are a common occurrence in the emergency department. Although recognition and diagnosis are relatively straightforward, discovering the cause and management should be approached systematically. The most important history items to ascertain is if the patient has symptoms and how long this imbalance has taken to develop. Treatment rapidity depends on severity of symptoms with the most rapid treatment occurring in only the severely symptomatic. Overcorrection has dire consequences and must be approached in a careful and systematic fashion in order to prevent these devastating consequences.

Use of Urea for the Syndrome of Inappropriate Secretion of Antidiuretic Hormone: A Systematic Review

Importance

Hyponatremia and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) are associated with significant mortality and morbidity. The effectiveness and safety of oral urea for SIADH are still debated.

Objective

To evaluate the efficacy and safety of urea for the treatment of SIADH.

Evidence Review

A systematic search of Medline and Embase was conducted for controlled and uncontrolled studies of urea for SIADH in adult patients. The primary outcome was serum sodium concentration after treatment. Secondary outcomes included the proportion of patients with osmotic demyelination syndrome (ODS), intracranial pressure, and resource use such as length of stay.

Findings

Twenty-three studies involving 537 patients with SIADH were included, of which 462 were treated with urea. The pooled mean baseline serum sodium was 125.0 mmol/L (95% CI, 122.6-127.5 mmol/L). The median treatment duration with oral urea was 5 days. Urea increased serum sodium concentration by a mean of 9.6 mmol/L (95% CI, 7.5-11.7 mmol/L). The mean increase in serum sodium after 24 hours was 4.9 mmol/L (95% CI, 0.5-9.3 mmol/L). Adverse events were few, mainly consisting of distaste or dysgeusia, and no case of ODS was reported. Resource use was too infrequently reported to be synthesized.

Conclusions and Relevance

In this systematic review of the use of urea in SIADH and despite the lack of randomized clinical trials, lower-quality evidence was identified that suggests that urea may be an effective, safe, and inexpensive treatment modality that warrants further exploration.

Severe Hyponatremia Correction, Mortality, and Central Pontine Myelinolysis

BACKGROUND: In clinical practice, sodium correction rates are frequently limited in patients with severe hyponatremia to prevent neurologic complications. The implications of correction rates on overall mortality and length of hospital stay are unclear. METHODS: In this multicenter observational study, we evaluated the association of sodium correction rates with mortality, length of stay, and central pontine myelinolysis (CPM) in patients hospitalized with severe hyponatremia (admission serum sodium level less than 120 mEq/l). RESULTS: The cohort included 3274 patients. A correction rate of less than 6 mEq/l/24 hours was observed in 38%, 6 to 10 mEq/l/24 hours was observed in 29%, and greater than 10 mEq/l/24 hours was observed in 33%. Compared with 6 to 10 mEq/l/24 hours, a correction rate of less than 6 mEq/l/24 hours exhibited higher in-hospital mortality in multivariable-adjusted and propensity score–weighted analyses. Compared with 6 to 10 mEq/l/24 hours, a correction rate of greater than 10 mEq/l/24 hours was associated with lower in-hospital mortality and shorter length of stay in multivariable analyses. Seven patients with CPM were identified, with five of seven developing CPM despite a sodium correction rate of less than or equal to 8 mEq/l/24 hours. Six of seven patients who developed CPM had alcohol use disorder, malnutrition, hypokalemia, or hypophosphatemia. CONCLUSIONS: Limiting the sodium correction rate was associated with higher mortality and longer length of stay. Whether the sodium correction rate influences neurologic complications needs further evaluation.

Validity of the Adrogué-Madias Formula for the Management of Acute Dysnatremias in Critically Ill Children: A Prospective Multicenter Analysis

OBJECTIVE

Current conventional formulas do not predict the expected changes in serum sodium after administration of various fluids to correct serum sodium abnormalities. The Adrogué-Madias formula is currently the preferred and widely used fluid prescription for adult patients with dysnatremias, but its therapeutic efficacy has not been validated in pediatric patients.

METHODS

In this prospective study, we used the Adrogué-Madias formula for calculating the appropriate rate of various fluids administration to correct serum sodium abnormalities in 7 critically ill children with acute dysnatremias.

RESULTS

After administration of various intravenous fluids using the Adrogué-Madias formula, the anticipated as well as the achieved sodium concentrations were almost similar.

CONCLUSIONS

This study demonstrates that the use of the Adrogué-Madias quantitative formula allows to calculate the appropriate rate of administration of various fluids. The calculated fluid administration resulted in the subsequent actual laboratory values and clinical changes.

[Hyponatremia : Etiology, diagnosis and acute therapy]

Hyponatremia is one of the most common electrolyte disorders in emergency departments and hospitalized patients. Serum sodium concentration is controlled by osmoregulation and volume regulation. Both pathways are regulated via the release of antidiuretic hormone (ADH). Syndrome of inappropriate release of ADH (SIADH) may be caused by neoplasms or pneumonia but may also be triggered by drug use or drug abuse. Excessive fluid intake may also result in a decrease in serum sodium concentration. Rapid alteration in serum sodium concentration leads to cell swelling or cell shrinkage, which primarily causes neurological symptoms. The dynamics of development of hyponatremia and its duration are crucial. In addition to blood testing, a clinical examination and urine analysis are essential in the differential diagnosis of hyponatremia.

Safety and Efficacy of Vaptans in the Treatment of Hyponatremia from Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH): A Systematic Review and Meta-Analysis

The utilization of vasopressin receptor antagonists, known as vaptans, in the management of hyponatremia among patients afflicted with the syndrome of inappropriate antidiuretic hormone (SIADH) remains a contentious subject. This meta-analysis aimed to evaluate the safety and efficacy of vaptans for treating chronic hyponatremia in adult SIADH patients. Clinical trials and observational studies were identified by a systematic search using MEDLINE, EMBASE, and Cochrane Database from inception through September 2022. The inclusion criteria were the studies that reported vaptans' safety or efficacy outcomes compared to placebo or standard therapies. The study protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD 42022357307). Five studies were identified, comprising three RCTs and two cohort studies, enrolling a total of 1840 participants. Regarding short-term efficacy on days 4-5, vaptans exhibited a significant increase in serum sodium concentration from the baseline in comparison to the control group, with a weighted mean difference of 4.77 mmol/L (95% CI, 3.57, 5.96; I2 = 34%). In terms of safety outcomes, the pooled incidence rates of overcorrection were 13.1% (95% CI 4.3, 33.6; I2 = 92%) in the vaptans group and 3.3% (95% CI 1.6, 6.6; I2 = 27%) in the control group. Despite the higher correction rate linked to vaptans, with an OR of 5.72 (95% CI 3.38, 9.70; I2 = 0%), no cases of osmotic demyelination syndrome were observed. Our meta-analysis comprehensively summarizes the efficacy and effect size of vaptans in managing SIADH. While vaptans effectively raise the serum sodium concentration compared to placebo/fluid restriction, clinicians should exercise caution regarding the potential for overcorrection.

Endocrinology of Underweight and Anorexia Nervosa

More than any other mental illness, the course, prognosis, and therapy of anorexia nervosa are shaped by the physical changes associated with being underweight. This article provides an overview of the endocrine changes associated with malnutrition and underweight. This overview serves as a basis for understanding the other articles in this special issue, which deal with the health risks associated with being underweight. In this context, the differences between underweight in anorexia nervosa and in constitutional thinness are of particular importance in assessing the impact of intentional weight loss. In this context, the regulation of hunger and satiety deserves special interest, as this is the area in which the intentional influence on body weight comes into play. Clinical consequences on, for example, fertility, bone metabolism, the homeostasis of, for example, serum glucose levels, or body temperature have been observed for a long time; nonetheless, the medical responses, apart from vitamin supplementations and advice to gain weight, are still limited. Therefore, emphasis was placed on the potential improvement of outcomes through the administration of central or peripheral hormones. Studies were identified on PubMed via a selection of relevant keywords; original texts that were cited in reviews were studied where it was advantageous. This review found some promising data on bone health and the administration of transdermal oestrogen, which is not yet widely used, as well as distinct hormonal markers to differentiate between CT and AN. We concluded that the continuous efforts to investigate the role of endocrinology in underweight and/or anorexia nervosa lead to outcome benefits and that more and higher-powered studies are needed.

Hyponatremia and Outcome: Is Severity More Important Than Etiology?

BACKGROUND AND OBJECTIVE

Hyponatremia is the most common electrolyte abnormality encountered in a hospital setting, and the data regarding the contribution of hyponatremia to overall mortality are conflicting. The study objective was to determine patients' clinical profiles and outcomes with hyponatremia.

METHODS

 This prospective cross-sectional study was conducted at Dayanand Medical College and Hospital, Ludhiana, and included 375 adult patients aged more than 18 years with a confirmed diagnosis of hyponatremia. Patients were subdivided into three groups based on the severity of hyponatremia: mild (130-135 mmol/L), moderate (125-129 mmol/L), and profound (<125 mmol/L).

RESULTS

The most common symptom was confusion (57.3%) followed by deep somnolence (40%) and nausea (36.8%). The most common cause of hyponatremia was diuretics (30.7%), followed by the syndrome of inappropriate antidiuretic hormone secretion (SIADH) (17.8%) and chronic liver disease (CLD) (14.1%). The severity of hyponatremia did not significantly influence the outcome. Patients with CLD and chronic kidney disease (CKD) as the etiology of hyponatremia had significantly worse outcomes compared to other causes of hyponatremia. The most common type was hypovolemic hypotonic followed by euvolemic hypotonic and hypervolemia hypotonic hyponatremia. Nearly half of the total deaths were observed in the hypervolemic hyponatremia group and were significantly higher compared to the other two groups (p=0.001). Correction of hyponatremia (i.e., serum sodium >135 mmol/L) was significantly linked with good outcomes (p=0.003).

CONCLUSION

Our study showed that the etiology of hyponatremia was a more important prognostic indicator rather than the severity of hyponatremia. Normalization of serum sodium was associated with improved survival.

Pituitary and SARS CoV-2: An unremitting conundrum

There is increased interest related to the impact of coronavirus disease 19 (COVID-19) on the endocrine system and in particular on the pituitary gland. Over the course of the severe infection with acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there are both acute and delayed effects on the pituitary, related to infection and/or treatment. Hypopituitarism, pituitary apoplexy and hypophysitis have been all reported, as well as arginine vasopressin deficiency (diabetes insipidus) and syndrome of inappropriate antidiuretic hormone secretion. Furthermore, patients with acromegaly, Cushing's disease and hypopituitarism are theoretically at increased risk of complications with COVID-19 and require close monitoring. Evidence regarding pituitary dysfunction in patients with COVID-19 continues to be gathered, as the breadth and depth of knowledge also continues to rapidly evolve. This review summarizes data analysis to date on the possible effects of COVID-19 and COVID-19 vaccination on patients with normal pituitary function and patients with known pituitary pathology. Though clinical systems were significantly affected, it seems there is no overall loss of biochemical control in patients with certain pituitary pathologies.

Overcoming Challenges: Doxycycline as an Alternative Treatment for Hyponatremia in Managing Syndrome of Inappropriate Secretion of Anti-diuretic Hormone (SIADH) in Small Cell Lung Cancer (SCLC): A Case Report

Hyponatremia, a common complication in small cell lung cancer (SCLC), can arise from various causes such as cancer itself, its treatment, paraneoplastic syndrome-induced SIADH secretion (syndrome of inappropriate anti-diuretic hormone secretion), and brain metastasis. While fluid restriction is the initial approach, refractory cases require pharmacological intervention in managing hyponatremia secondary to SIADH. This case report presents doxycycline as an alternative treatment option for a patient with refractory hyponatremia and SCLC with brain metastases, resulting in improved serum sodium levels. However, the use of doxycycline was associated with acute pancreatitis, prompting its discontinuation without establishing a definitive causal relationship. This case report highlights the importance of alternative treatments in resource-limited settings and emphasizes personalized care for hyponatremia in SCLC patients. Doxycycline can be an option, but safety and effectiveness require further study.

Treatment Guidelines for Hyponatremia: Stay the Course

International guidelines designed to minimize the risk of complications that can occur when correcting severe hyponatremia have been widely accepted for a decade. On the basis of the results of a recent large retrospective study of patients hospitalized with hyponatremia, it has been suggested that hyponatremia guidelines have gone too far in limiting the rate of rise of the serum sodium concentration; the need for therapeutic caution and frequent monitoring of the serum sodium concentration has been questioned. These assertions are reminiscent of a controversy that began many years ago. After reviewing the history of that controversy, the evidence supporting the guidelines, and the validity of data challenging them, we conclude that current safeguards should not be abandoned. To do so would be akin to discarding your umbrella because you remained dry in a rainstorm. The authors of this review, who represent 20 medical centers in nine countries, have all contributed significantly to the literature on the subject. We urge clinicians to continue to treat severe hyponatremia cautiously and to wait for better evidence before adopting less stringent therapeutic limits.

Frequency of Hyponatremia and Its Impact on Prognosis in Ischemic Stroke

Background Hyponatremia, often encountered in hospitalized patients, is associated with adverse outcomes in ischemic stroke patients. In this study, we investigated the frequency of hyponatremia and its impact on prognosis and clinical outcomes in ischemic stroke patients from a tertiary care hospital. Methodology A total of 289 patients admitted to the hospital with ischemic stroke from September 2022 to February 2023 were considered in this cross-sectional study. Serum sodium level was measured on admission, and hyponatremia was defined as sodium less than 135 mmol/L. The primary outcome of the study was assessed by the National Institutes of Health Stroke Scale (NIHSS) score on admission and discharge and inpatient mortality. Data were analyzed using SPSS version 20 (IBM Corp., Armonk, NY, USA), and multivariate logistic regressions were conducted using variables identified as having a relationship with hyponatremia. Results Our study shows that among 289 patients with ischemic stroke, the mean age was 61 ± 8.53 years. Hyponatremia was observed in 101 (35%) patients, and all baseline characteristics and risk factors for stroke were similar between patients with and without hyponatremia. The patients with hyponatremia had higher NIHSS scores on admission (p = 0.041) and at discharge (p = 0.039). In the resultant multivariate analysis, hyponatremia was an independent predictor of mortality rates during the hospital stay. The cumulative incidence rates of in-hospital mortality for hyponatremia and normal sodium level were 16.8% and 10.1%, respectively. Conclusions Hyponatremia is prevalent in ischemic stroke and is independently associated with in-hospital mortality and worse NIHSS scores at admission and discharge.

Copeptin: Up-to-date diagnostic and prognostic role highlight

Arginine Vasopressin (AVP) is one of the key hormones in the human body. AVP is clinically important because it maintains body fluid balance and vascular tone. Unfortunately, AVP laboratory measurements are always difficult and with low accuracy. Copeptin, the C-terminal of the AVP precursor, is released in equal amounts with AVP, making it a sensitive marker of AVP release. Despite being a non-specific biomarker, copeptin earned a lot of attention as a novel biomarker due to easy and quick laboratory measurements. Recent studies have reported the critical role of copeptin as a clinical indicator, especially in the diagnosis and prognosis of many diseases. Besides, it was reported that the combination between copeptin and gold standard biomarkers improved the prognostic values of those biomarkers. In this review, the role of copeptin as a new predictive diagnostic and prognostic biomarker of various diseases is highlighted according to the most recent studies. In addition, the importance of using copeptin as a marker in different medical departments and the impact of this on improving healthcare service was discussed.

[Electrolyte disorders in oncological patients]

Electrolyte disorders (ED) are common in patients with cancer and in most cases, the etiologies do not differ from the general population. They may also be induced by the cancer, its therapy or paraneoplastic syndromes. ED are associated with poor outcomes, increased morbidity and mortality in this population. Hyponatremia is the most common disorder, often multifactorial, iatrogenic or secondary to the syndrome of inappropriate antidiuretic hormone secretion, usually due to small cell lung cancer. More rarely, hyponatremia may reveal adrenal insufficiency. Hypokalemia is generally multifactorial and associated with other ED. Cisplatin and ifosfamide induce proximal tubulopathies with hypokalemia and/or hypophosphatemia. Hypomagnesemia is often iatrogenic, related to cisplatin or cetuximab, but can be prevented by supplementation. Hypercalcemia can impair life quality and be life-threatening in the most severe cases. Hypocalcemia is less common and often of iatrogenic origin. Finally, the tumor lysis syndrome is a diagnostic and therapeutic emergency that affects the prognosis of patients. Its incidence tends to increase in solid oncology, related to the improvement of therapies. Prevention and early diagnosis of ED are essential to optimize the overall management of patients with underlying cancer and cancer therapy. The aim of this review is to synthesize most frequent ED and their management.

A profile of SGLT-2 inhibitors in hyponatremia: The evidence to date

Hyponatremia is the most common electrolyte disorder in clinical practice, which may lead to life-threatening complications. Several lines of evidence suggest that hyponatremia is associated not only with significant increases in length of stay, cost, and financial burden, but also with increased morbidity and mortality. Hyponatremia is also considered to be a negative prognostic factor in patients with heart failure and cancer. Although multiple therapeutic methods are available for treating hyponatremia, most have some limitations, such as poor compliance, rapid correction of serum Na⁺, other negative side effects and high cost. Given these limitations, identifying novel therapies for hyponatremia is essential. Recent clinical studies have shown that SGLT-2 inhibitors (SGLT 2i) significantly increased serum Na⁺ levels and were well tolerated by patients who underwent this treatment. Therefore, oral administration of SGLT 2i appears to be an effective treatment for hyponatremia. This article will briefly review the etiology of hyponatremia and integrated control of sodium within the kidney, current therapies for hyponatremia, potential mechanisms and efficacy of SGLT 2i for hyponatremia, and the benefits in cardiovascular, cancer, and kidney disease by regulating sodium and water balance.

A Case of Flecainide-Induced Hyponatremia

The complex classification for the diagnosis and treatment illustrates that hyponatremia is a very heterogeneous disorder. However, data on hyponatremia induced by flecainide, an often-prescribed antiarrhythmic agent, are scarce in the literature. A 78-year-old man with a recent history of recurrent hyponatremia and symptomatic paroxysmal atrial fibrillation presented with the complaints of dizziness and fatigue. During his repeated hospital admissions, the patient was treated with hypertonic saline, which temporarily improved serum sodium levels, but hyponatremia recurred without sustained clinical improvement. After discontinuation of the drug, the sodium levels remained stable. Doctors should be aware of not only the electrocardiographic changes associated with flecainide, but also the less-often found clinical manifestations linked with hyponatremia.

Administration of 3% hypertonic saline via peripheral route: Is it really safe?

BACKGROUND

Administration of 3% sodiumchloride through a peripheral venous catheter is associated with risk of infusion-related adverse events (IRAE) due to its high osmolarity. Given this concern and the paucity of data regarding these events,many hospitals have policies that require central line administration of 3% sodiumchloride.

OBJECTIVE

The objective of this analysis was to evaluate the incidence of IRAE associated with peripheral administration of 3% sodium chloride.

METHODS

This analysis included patients who received 3% sodium chloride via a peripheral venous catheter between May 2017 and August 2019. The major endpoint of this analysiswas the overall incidence of IRAE, defined as the documentation of infiltration or phlebitis. Amultivariable logistic regression was performed to identify potential risk factors (e.g., age, infusion rate, infusion duration, peripheral venous catheter location, and needle gauge) for development of IRAE.

RESULTS

A total of 706 administrations in 422 patientswere included. Seventy-four (10.5%) administrations were associated with a documented event. Based on the Infusion Nurses grading scale for infiltration or phlebitis, 48% of the events in this analysiswere grade 1 in severity. Duration of infusion of 3% sodiumchloride was found to be associated with an increased odds of an IRAE (OR per 1 h 1.02, 95% CI 1.01-1.02) in the multivariable analysis. Age, infusion rate, peripheral venous catheter location, and needle gauge were not independently associated with an increased risk of an IRAE.

CONCLUSION

These data suggest that IRAE occurred more frequently when 3% sodium chloride was administered over a longer duration and themajority of events weremild with no permanent tissue injury. Itmay be reasonable to consider peripheral administration of 3% sodium chloride in the acute care setting for a short duration, although additional studies are needed to continue to evaluate its safety.

Syndrome of Inappropriate Antidiuretic Hormone Secretion as a Presentation of Untreated Parkinson's Disease

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common electrolyte disorder associated with neurological conditions. Parkinson's disease (PD) has not been known to be causative of SIADH. We present the case of a 71-year-old male patient with diabetes type II (T2DM) and hypothyroidism admitted with progressive confusion, slow speech, and severe fatigue for one week, accompanied by sluggish body movements for a few months. A neurological exam revealed mild arm rigidity, bradykinesia, resting tremors, and stiff gait. The exam was otherwise normal. Initial blood work showed hypo-osmolar hyponatremia (Na 122 mEq/L, serum osmolarity (Osm) 275 mOsm/kg, and urine Osm 672 mOsm/Kg). CT chest showed localized infiltrate. The initial diagnosis was SIADH secondary to pulmonary process, most probably pneumonia. After starting him on a fluid restriction of 1.5 L/day and urea 15 mg BID, sodium improved gradually to 133 mEq/L on discharge. Urine osmolality continued to be elevated ranging between 700 and 800 mOsm/Kg. An active pulmonary process was ruled out by a pulmonologist. Parkinsonism was diagnosed four weeks after discharge by Neurology who started carbidopa/levodopa. As extrapyramidal symptoms improved, urine osmolality improved as well to 400 mOsm/Kg. Sodium level was maintained between 135 and 137 while urea treatment was stopped and fluid restrictions removed. New-onset SIADH was thought to be secondary to Parkinson's disease. Parkinson's disease treatment (carbidopa/levodopa) is known to cause SIADH. In this case, the treatment itself and a dose increase led to improvement in sodium levels and urine osmolality concomitantly with the improvement of the patient's extrapyramidal symptoms.

Hypertonic Saline Infusion for Hyponatremia: Limitations of the Adrogué-Madias and Other Formulas

Hypertonic saline infusion is used to correct hyponatremia with severe symptoms. The selection of the volume of infused hypertonic saline ( VInf ) should address prevention of overcorrection or undercorrection. Several formulas computing this VInf have been proposed. The limitations common to these formulas consist of (1) failure to include potential determinants of change in serum sodium concentration ([ Na ]) including exchanges between osmotically active and inactive sodium compartments, changes in hydrogen binding of body water to hydrophilic compounds, and genetic influences and (2) inaccurate estimates of baseline body water entered in any formula and of gains or losses of water, sodium, and potassium during treatment entered in formulas that account for such gains or losses. In addition, computing VInf from the Adrogué-Madias formula by a calculation assuming a linear relation between VInf and increase in [ Na ] is a source of errors because the relation between these two variables was proven to be curvilinear. However, these errors were shown to be negligible by a comparison of estimates of VInf by the Adrogué-Madias formula and by a formula using the same determinants of the change in [ Na ] and the curvilinear relation between this change and VInf . Regardless of the method used to correct hyponatremia, monitoring [ Na ] and changes in external balances of water, sodium, and potassium during treatment remain imperative.

Hyponatremia Treatment Guidelines - Have They Gone Too Far?

Hyponatremia is a common electrolyte abnormality affecting hospitalized patients.1 It is an independent predictor for mortality and is associated with increased length of hospital stay and higher costs. The most serious potential complication is hyponatremic encephalopathy, a medical emergency that can result in death or irreversible brain injury if inadequately treated.2 Hypertonic saline is a safe and effective means of correcting hyponatremia.2-4 A rare yet serious complication from excessive correction of chronic hyponatremia is the development of cerebral demyelination.

[Dysnatremia]

Changes in serum sodium concentrations are frequently encountered by anesthesiologists, are complex and are often inadequately treated. Feared consequences include neurological complications, such as cerebral hemorrhage, cerebral edema and coma. Dysnatremia is always accompanied disturbances in the water balance. Accordingly, these are routinely classified based on the tonicity; however, in the daily routine and especially in the acute setting, the volume status and extracellular volume are often difficult to assess. Severe symptomatic hyponatremia with impending cerebral edema is treated by administration of hypertonic saline solution. If the rise in serum sodium is too rapid, there is a risk of central pontine myelinolysis. In a second step, the cause of the hyponatremia can be investigated and the appropriate treatment can be initiated. In the case of hypernatremia, the etiology of the disorder must be clarified before treatment. The goal is to compensate for the water deficiency by correcting the cause, specific volume therapy and, if necessary, drug support. A slow and controlled compensation must be closely monitored in order to avoid neurological complications. An algorithm has been developed that provides an overview of the dysnatremias, aids with making the diagnosis and gives recommendations for treatment measures in the clinical routine.

Retrospective analysis of patients diagnosed with severe hyponatraemia in the emergency department

Background . We investigated the demographic, aetiological and clinical characteristics of patients who presented to the emergency department and had severe hyponatraemia. Methods . We retrospectively evaluated 1171 patients who presented to the emergency department and were diagnosed with severe hyponatraemia. Results . Over half the patients studied were women (53.5%). The mean age of women was higher (p<0.0001). The most common complaint was dyspnoea (16.8%) and 42.5% of the patients had an oral intake disorder. In addition, 22.3% of the patients were on loop diuretics. About 76.3% of patients were conscious, and the mean sodium level of these patients was higher than the mean sodium level of those who responded to verbal and painful stimuli (p<0.001). Severe isolated hyponatraemia was observed in 61.8% of the patients. The mortality rate was 12.8%. There was no difference between the mean sodium levels of the deceased and discharged patients (p=1.0). The mortality rate was higher in patients who had a history of cirrhosis and cancer, but was lower in patients with a history of coronary artery disease (p=0.0002, p<0.0001 and p=0.04, respectively). Conclusion . Severe hyponatraemia was more prevalent in women, serum sodium levels were higher in conscious patients, and the mortality rate was higher in patients who had a history of cirrhosis and cancer. We found that the mean serum sodium levels did not help in distinguishing between the deceased and discharged patients.

Consensus document on the management of hyponatraemia of the Acqua Group of the Spanish Society of Endocrinology and Nutrition

INTRODUCTION

Hyponatremia is the most prevalent electrolyte disorder in the outpatient and inpatient settings. Despite this frequency, hyponatremia, including severe hyponatremia, is frequently underestimated and inadequately treated, thus highlighting the need to produce consensus documents and clinical practice guidelines geared towards improving the diagnostic and therapeutic approach to it in a structured fashion.

MATERIAL AND METHODS

Members of the Acqua Group of the Spanish Society of Endocrinology and Nutrition (SEEN) met using a networking methodology over a period of 20 months (between October 2019 and August 2021) with the aim of discussing and developing an updated guideline for the management of hyponatraemia. A literature search of the available scientific evidence for each section presented in this document was performed.

RESULTS

A document with 8 sections was produced, which sets out to provide updated guidance on the most clinically relevant questions in the management of hyponatraemia. The management of severe hyponatraemia is based on the i.v. administration of a 3% hypertonic solution. For the management of chronic euvolemic hyponatraemia, algorithms for the initiation of treatment with the two pharmacological therapeutic options currently available in Spain are presented: urea and tolvaptan.

CONCLUSIONS

This document sets out to simplify the approach to and the treatment of hyponatraemia, making it easier to learn and thus improve the clinical approach to hyponatremia.

Urinary albumin-to-creatinine ratio and serum albumin are predictors of acute kidney injury in non-ventilated COVID-19 patients: a single-center prospective cohort study

PURPOSE

Acute kidney injury (AKI) is a frequent complication among COVID-19 patients in the intensive care unit, but it is less frequently investigated in general internal medicine wards. We aimed to examine the incidence, the predictors of AKI, and AKI-associated mortality in a prospective cohort of non-ventilated COVID-19 patients. We aimed to describe the natural history of AKI by describing trajectories of urinary markers of hemodynamic, glomerular, and tubular injury.

METHODS

141 COVID-19 patients were enrolled to the study. AKI was defined according to KDIGO guidelines. Urine and renal function parameters were followed twice a week. Multivariate logistic regression was used to determine the predictors of AKI and mortality. Trajectories of urinary markers were described by unadjusted linear mixed models.

RESULTS

19.7% patients developed AKI. According to multiple logistic regression, higher urinary albumin-to-creatinine ratio (OR 1.48, 95% CI 1.04-2.12/1 mg/mmol) and lower serum albumin (OR 0.86, 95% CI 0.77-0.94/1 g/L) were independent predictors of AKI. Mortality was 42.8% in the AKI and 8.8% in the group free from AKI (p < 0.0001). According to multiple logistic regression, older age, lower albumin, and AKI (OR 3.9, 95% CI 1.24-12.21) remained independent predictors of mortality. Urinary protein-to-creatinine trajectories were diverging with decreasing values in those without incident AKI.

CONCLUSION

We found high incidence of AKI and mortality among moderately severe, non-ventilated COVID-19 patients. Its development is predicted by higher albuminuria suggesting that the originally damaged renal structure may be more susceptible for virus-associated effects. No clear relationship was found with a prerenal mechanism, and the higher proteinuria during follow-up may point toward tubular damage.

Hyponatremia Demystified: Integrating Physiology to Shape Clinical Practice

Hyponatremia is one of the most common problems encountered in clinical practice and one of the least-understood because accurate diagnosis and management require some familiarity with water homeostasis physiology, making the topic seemingly complex. The prevalence of hyponatremia depends on the nature of the population studied and the criteria used to define it. Hyponatremia is associated with poor outcomes including increased mortality and morbidity. The pathogenesis of hypotonic hyponatremia involves the accumulation of electrolyte-free water caused by either increased intake and/or decrease in kidney excretion. Plasma osmolality, urine osmolality, and urine sodium can help to differentiate among the different etiologies. Brain adaptation to plasma hypotonicity consisting of solute extrusion to mitigate further water influx into brain cells best explains the clinical manifestations of hyponatremia. Acute hyponatremia has an onset within 48 hours, commonly resulting in severe symptoms, while chronic hyponatremia develops over 48 hours and usually is pauci-symptomatic. However, the latter increases the risk of osmotic demyelination syndrome if hyponatremia is corrected rapidly; therefore, extreme caution must be exercised when correcting plasma sodium. Management strategies depend on the presence of symptoms and the cause of hyponatremia and are discussed in this review.

Severe hyponatraemia (P-Na < 116 mmol/l) in the emergency department: a series of 394 cases

AIM

To evaluate the significance of severe hyponatraemia presented at the emergency department (ED).

METHODS

A retrospective hospital records study of all patients with plasma sodium levels of < 116 mmol/l from 2016 to 2020 in a single tertiary referral centre.

RESULTS

A total of 394 visits of 363 individual severely hyponatraemic patients represented 0.08% of all ED visits. The mean age was 68 years and the male-to-female ratio was 1:1.3. The symptoms and signs were diffuse and varying, while half of the patients had neurologic symptoms. The aetiology of hyponatraemia was often multifactorial. The aetiologies varied by age, and the most common ones were the syndrome of inappropriate antidiuresis (34%), diuretic use (27%), alcohol-related (19%) and dehydration (19%). The mean sodium correction rates were 6.6, 4.9 and 3.8 mmol/l/24 h at 24, 48 and 72 h, respectively. The mean maximum correction rate over any 24-h time interval was 10.2 mmol/l. The vital signs (National Early Warning Score, NEWS) of severely hyponatraemic patients were mostly normal. All-cause mortality was 18% for 1-year follow-up. Malignancies, especially small-cell lung cancer, and end-stage liver disease caused most of the deaths. Osmotic demyelination syndrome (ODS) was diagnosed in five (1.4%) patients.

CONCLUSION

Patients with severe hyponatraemia in the ED presented with non-specific complaints. The aetiology of hyponatraemia was often multifactorial and varied by age. The need for intensive care was poorly predicted by NEWS. The one-year mortality rate was 18% and the incidence of ODS 1.4% after an episode of severe hyponatraemia.

Serum sodium, cognition and incident dementia in the general population

BACKGROUND

Low serum sodium may be associated with cognitive impairment and dementia in the general population, but the data remain inconclusive. Therefore, we aimed to determine the association of low serum sodium with cognitive function and incident dementia in the general population.

METHODS

Participants from a prospective population-based cohort were eligible if data on serum sodium (collected between 1997 and 2008), dementia prevalence and dementia incidence were available (follow-up until 2018). Global cognitive function was assessed with the Mini-Mental State Examination (MMSE) and the general cognitive factor (G-factor, derived from principal component analysis of individual tests). Linear regression and Cox proportional-hazards models were used to assess associations of standardised continuous and categorised low serum sodium (mean - 1.96*SD: cut-off of 137 mmol/L) with overall cognitive function and incident dementia, respectively.

RESULTS

In all, 8,028 participants free of dementia at baseline (mean age 63.6 years, 57% female, serum sodium 142 ± 2 mmol/L), including 217 participants with low serum sodium, were included. Cross-sectionally, continuous serum sodium and/or low serum sodium were not associated with the MMSE or G-factor. However, participants with low serum sodium performed worse on the Stroop and Purdue Pegboard tests. During a median follow-up of 10.7 years, 758 subjects developed dementia. Continuous serum sodium (hazard ratio (HR) 0.98, 95% confidence interval (CI) 0.92;1.05) and low serum sodium (HR 1.27, 95% CI 0.90;1.79) were not associated with a higher risk of incident dementia.

CONCLUSION

We identified no significant associations of low serum sodium with overall cognitive functioning and risk of dementia. However, low serum sodium-including levels above the clinical cut-off for hyponatremia-was associated with impairments in selected cognitive domains including attention and psychomotor function.

Performance specifications for sodium should not be based on biological variation

When increasing the quality in clinical laboratories by decreasing measurement uncertainty, reliable methods are needed not only to quantify the performance of measuring systems, but also to set goals for the performance. Sigma metrics used in medical laboratories for documenting and expressing levels of performance, are evidently totally dependent on the "total permissible error" used in the formulas. Although the conventional biological variation (BV) based model for calculation of the permissible (or allowable) total error is commonly used, it has been shown to be flawed. Alternative methods are proposed, mainly also based on the within-subject BV. Measurement uncertainty models might offer an alternative to total error models. Defining the limits for analytical quality still poses a challenge in both models. The aim of the present paper is to critically discuss current methods for establishing performance specifications by using the measurement of sodium concentrations in plasma or serum. Sodium can be measured with high accuracy but fails by far to meet conventional performance specifications based on BV. Since the use of sodium concentrations is well established for supporting clinical care, we question the concept that quality criteria for sodium and similar analytes that are under strict homeostatic control are best set by biology.

Risk factors for hyponatremia in acute exacerbation chronic obstructive pulmonary disease (AECOPD): a multicenter cross-sectional study

BACKGROUND

Hyponatremia is an independent predictor of poor prognosis, including increased mortality and readmission, in COPD patients. Identifying modifiable etiologies of hyponatremia may help reduce adverse events in patients with AECOPD. Therefore, the aim of this study was to explore the risk factors and underlying etiologies of hyponatremia in AECOPD patients.

METHODS

A total of 586 AECOPD patients were enrolled in this multicenter cross-sectional study. Finally, 323 had normonatremia, and 90 had hyponatremia. Demographics, underlying diseases, comorbidities, symptoms, and laboratory data were collected. The least absolute shrinkage and selection operator (LASSO) regression was used to select potential risk factors, which were substituted into binary logistic regression to identify independent risk factors. Nomogram was built to visualize and validate binary logistics regression model.

RESULTS

Nine potential hyponatremia-associated variables were selected by LASSO regression. Subsequently, a binary logistic regression model identified that smoking status, rate of community-acquired pneumonia (CAP), anion gap (AG), erythrocyte sedimentation rate (ESR), and serum magnesium (Mg²⁺) were independent variables of hyponatremia in AECOPD patients. The AUC of ROC curve of nomogram was 0.756. The DCA curve revealed that the nomogram could yielded more clinical benefits if the threshold was between 10% and 52%.

CONCLUSIONS

Collectively, our results showed that smoking status, CAP, AG, ESR, and serum Mg²⁺ were independently associated with hyponatremia in AECOPD patients. Then, these findings indicate that pneumonia, metabolic acidosis, and hypomagnesemia were the underlying etiologies of hyponatremia in AECOPD patients. However, their internal connections need further exploration.

Hyponatremic encephalopathy due to polyethylene glycol-based bowel preparation for colonoscopy: A case report

BACKGROUND

Adequate bowel preparation is critical for colonoscopy screening. At present, the most widely used intestinal cleaner recommended at home and abroad is Polyethylene glycol (PEG). Intestinal cleansers can cause electrolyte disturbances and hyponatremia. However, hyponatremic encephalopathy due to hyponatremia induced by PEG solution, although rare, can lead to serious irreversible sequelae and even death.

CASE SUMMARY

In this report, we discuss a case of neurological dysfunction due to hyponatremia, also known as hyponatremic encephalopathy, observed in a 63-year-old woman who underwent PEG-based bowel preparation for colonoscopy. She was eventually transferred to our intensive care unit for treatment due to her Glasgow Coma Scale score of 9/15 (Eye opening 2; Verbal response 1; Motor response 6) and abnormal laboratory tests.

CONCLUSION

Physicians should be thoroughly familiarized with the patient's history before prescribing PEG for bowel preparation, and timely identification of patients with hyponatremic encephalopathy is essential as delayed treatment is associated with poor neurological outcomes. An intravenous infusion of 3% sodium chloride is recommended at the onset of early symptoms. The goal of treatment is to adequately treat cerebral edema while avoiding serum sodium correction beyond 15 to 20 mEq/L within 48 h of treatment to prevent osmotic demyelination syndrome.

The Association Between Hyponatremia and Optic Nerve Sheath Diameter: A Prospective Study

Background Hyponatremia is a common electrolyte balance disorder. It may result in brain edema and increased intracranial pressure (ICP). Optic nerve sheath diameter (ONSD) measurement remains an increasingly sought-after method in many situations associated with ICP elevations. The aim of our study was to investigate the relationship between the change of ONSD before and after hypertonic saline (3% sodium chloride) treatment and the clinical improvement with increased sodium levels in patients with symptomatic hyponatremia who presented to the emergency department. Methodology This study was conducted in the emergency department of a tertiary hospital, according to the design of a prospective, self-controlled, non-randomized trial study. Determined by power analysis, 60 patients were included in the study. The statistical analysis of the continuous data was performed using the means, standard deviations, and minimum and maximum values of the feature values. The frequency and percentage values were used to define categorical variables. The mean difference comparison of pre-and post-treatment measurements was evaluated by paired t-test. P<0.05 was considered to be significant. Results The measurement parameters' differences before and after hypertonic saline treatment were evaluated. While the mean of the right eye ONSD was 5.27±0.22 mm before treatment, it declined substantially to 4.52±0.24 mm after treatment (p<0.001). It was also found that the left eye ONSD was 5.26±0.23 mm before the treatment and declined to 4.53±0.24 mm after the treatment (p<0.001). In addition, the mean of the overall ONSD was 5.26±0.23 mm before treatment and 4.52±0.24 mm after treatment (p<0.001). Conclusions Ultrasonic measurement of ONSD can be used to monitor the clinical improvement of patients receiving hypertonic saline therapy for symptomatic hyponatremia.

Safely correct hyponatremia with continuous renal replacement therapy: A flexible, all-purpose method based on the mixing paradigm

Treating chronic hyponatremia by continuous renal replacement therapy (CRRT) is challenging because the gradient between a replacement fluid's [sodium] and a patient's serum sodium can be steep, risking too rapid of a correction rate with possible consequences. Besides CRRT, other gains and losses of sodium- and potassium-containing solutions, like intravenous fluid and urine output, affect the correction of serum sodium over time, known as osmotherapy. The way these fluids interact and contribute to the sodium/potassium/water balance can be parsed as a mixing problem. As Na/K/H₂ O are added, mixed in the body, and drained via CRRT, the net balance of solutes must be related to the change in serum sodium, expressible as a differential equation. Its solution has many variables, one of which is the sodium correction rate, but all variables can be evaluated by a root-finding technique. The mixing paradigm is proved to replicate the established equations of osmotherapy, as in the special case of a steady volume. The flexibility to solve for any variable broadens our treatment options. If the pre-filter replacement fluid cannot be diluted, then we can compensate by calculating the CRRT blood flow rate needed. Or we can deduce the infusion rate of dextrose 5% water, post-filter, to appropriately slow the rise in serum sodium. In conclusion, the mixing model is a generalizable and practical tool to analyze patient scenarios of greater complexity than before, to help doctors customize a CRRT prescription to safely and effectively reach the serum sodium target.

Hyponatremia in peritoneal dialysis patients

Hyponatremia is the most common disorder of body fluid and electrolyte balance encountered in clinical practice, and also in peritoneal dialysis (PD) population. Depending on the severity and the speed of drop in sodium concentration, the symptoms can vary from asymptomatic hyponatremia to mild and non-specific symptoms or severe and life-threatening situations. Hyponatremia is associated with high morbidity and mortality. Its pathophysiology is complex, specifically in patients undergoing PD. The etiological workup can be cumbersome but is of paramount importance for early and appropriate treatment. In this article, we review the clinical manifestations as well as the pathophysiology and the specific etiologies of hyponatremia in peritoneal dialysis patients, and we propose a diagnostic algorithm.