Development of severe hyponatraemia in hospitalized patients: treatment-related risk factors and inadequate management

Syndrome of inappropriate antidiuresis/hyponatremia in COVID-19

Hyponatremia is the most frequent electrolyte alteration among hospitalized patients and it has been reported in 20-40% of patients with SARS-CoV-2 (COVID-19) infection. Multiple causes of hyponatremia have been hypothesized in these patients. The syndrome of inappropriate antidiuresis (SIAD) has been considered one of the main reasons leading to hyponatremia in this condition. SIAD can be secondary to cytokines release, in particular IL-6. Positive pressure ventilation can be another cause of hyponatremia due to SIAD. Other possible etiologies of hyponatremia in COVID-19 patients can be related to secondary hypocortisolism, nausea, vomiting, heart and kidney damage. Similar to many other clinical conditions, there is strong evidence that hyponatremia is associated with a worse prognosis also in patients with COVID-19 infection. In particular, hyponatremia has been identified as an independent risk of ICU transfer, need of non-invasive ventilation and death. Hyponatremia in COVID-19 patients is in principle acute and symptomatic and should be treated as such, according to the published guidelines. Therefore, patients should be initially treated with i.v. hypertonic saline (3% NaCl) infusion and serum [Na+] should be frequently monitored, in order to remain within a safe rate of correction. There is evidence showing that serum [Na+] correction is associated with a better outcome in different pathologies, including COVID-19 infection.

Hyponatremia in the emergency department: an overview of diagnostic and therapeutic approach

INTRODUCTION

Hyponatremia, defined as a serum sodium concentration <135 mmol/l, is a frequent electrolyte disorder in patients presenting to an emergency department (ED). In this context, appropriate diagnostic and therapeutic management is rarely performed and challenging due to complex pathophysiologic mechanisms and a variety of underlying diseases.

OBJECTIVE

To implement a feasible pathway of central diagnostic and therapeutic steps in the setting of an ED.

METHODS

We conducted a narrative review of the literature, considering current practice guidelines on diagnosis and treatment of hyponatremia. Underlying pathophysiologic mechanisms and management of adverse treatment effects are outlined. We also report four cases observed in our ED.

RESULTS

Symptoms associated with hyponatremia may appear unspecific and range from mild cognitive deficits to seizures and coma. The severity of hyponatremia-induced neurological manifestation and the risk of poor outcome is mainly driven by the rapidity of serum sodium decrease. Therefore, emergency treatment of hyponatremia should be guided by symptom severity and the assumed onset of hyponatremia development, distinguishing acute (<48 hours) versus chronic hyponatremia (>48 hours).

CONCLUSIONS

Especially in moderately or severely symptomatic patients presenting to an ED, the application of a standard management approach appears to be critical to improve overall outcome. Furthermore, an adequate work-up in the ED enables further diagnostic and therapeutic evaluation during hospitalization.

Relationship of severity of hyponatremia and adverse outcomes in children visiting the emergency department

Mild hyponatremia is often found in patients visiting pediatric emergency departments (PEDs), but there are few large-scale studies on its association with adverse outcomes, including mortality. We conducted this study to identify the association of mild hyponatremia with adverse outcome. This retrospective observational study included children under 18 years of age visiting the PED at a tertiary hospital. We used electronic medical record data from January 1, 2009 to December 31, 2020. Clinical outcomes, including ward admission, vasopressor administration, pediatric intensive care unit (PICU) admission, and mortality, were assessed for the total of 44,147 patients. Among these, 1,639 (3.7%) were in the hyponatremia group, with 1,521 (3.4%) exhibiting mild hyponatremia. Mild hyponatremia was more prevalent in younger patients, particularly in the 1-3 years age group, and less common in females. Patients with mild hyponatremia had a significantly prolonged median length of stay in the PED compared to normonatremic patients (5.8 h vs. 4.4 h, p < 0.001). Moreover, they showed significantly higher rates of ward admission (51.1% vs. 35.6%, p < 0.001), vasopressor administration (1.1% vs. 0.6%, p = 0.014), PICU admission (2.4% vs. 1.0%, p < 0.001), and mortality (1.5% vs. 0.3%, p < 0.001). Compared with the normonatremia group, the odds ratios (95% CI) for ward admission, vasopressor administration, PICU admission, and mortality in the mild hyponatremia group were 1.90 (1.71-2.10), 1.91 (1.17-3.13), 2.62 (1.86-3.68), and 5.56 (3.51-8.80), respectively. Furthermore, our findings demonstrate a notable upward trend in adverse outcomes, including vasopressor administration, PICU admission, and mortality, from mild hyponatremia to severe hyponatremia. In conclusion, we found that adverse outcomes increase with the severity of hyponatremia in children presenting to the PED, highlighting the importance of immediate intervention alongside the identification of the underlying cause.

Association of Pre-Operative Hyponatraemia with Morbidity and Mortality in Patients Undergoing Non-Urgent Degenerative Spine Surgery, a Retrospective Study

BACKGROUND AND OBJECTIVES

Hyponatraemia increases the morbidity and mortality risks of orthopaedic patients. When undergoing spine surgery, hyponatraemic patients have high risks of pneumonia and of staying in hospital for up to 1 day longer compared with non-hyponatraemic patients. This study aims to assess the occurrence of adverse events among patients with pre-operative hyponatraemia after undergoing lumbar surgery.

MATERIALS AND METHODS

A retrospective cohort study was conducted. Patients who underwent spinal surgery in 2011 to 2013 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Multivariate analysis was conducted to demonstrate the difference in post-operative complication rates between hyponatraemic patients and normonatraemic patients. Post-operative adverse events, need for blood transfusion and length of stay were considered as clinical outcome data.

RESULTS

A total of 58,049 patients were included; pre-operatively, 55,012 (94.8%) were normonatraemic and 3037 (5.2%) were hyponatraemic. Multivariate analysis showed that hyponatraemic patients had higher rates of adverse events, blood transfusions and urinary tract infections. Specifically, 632 (20.8%) hyponatraemic patients developed adverse events, compared with 6821 (12.4%) normonatraemic patients; the hyponatraemic patients received transfusions, compared with 6821 (7.4%) normonatraemic patients; and 97 (3.2%) hyponatraemic patients developed urinary tract infections, compared with 715 (1.3%) normonatraemic patients. Finally, an extended length of stay beyond 6 days occurred in 604 (19.9%) hyponatraemic patients, compared with 4676 (8.5%) normonatraemic patients.

CONCLUSIONS

Our study identified an association between pre-operative hyponatraemia and post-operative adverse events in spinal surgery patients. However, it is unclear whether hyponatraemia caused the higher adverse event rate.

Low Prevalence of Clinically Significant Hyponatremia following Cranial Vault Reconstruction for Single-Suture Craniosynostosis

BACKGROUND

Patients are commonly monitored for hyponatremia after intracranial procedures, yet the prevalence of hyponatremia after cranial vault reconstruction (CVR) remains unclear. The purpose of this study is to define the prevalence, risk factors, and complications of hyponatremia after CVR to optimize postoperative sodium surveillance protocols.

METHODS

Patients with nonsyndromic, single-suture craniosynostosis who underwent primary CVR between 2009 and 2020 at Michigan Medicine were included (n = 231). Demographic, intraoperative, and postoperative characteristics were compared by postoperative hyponatremia status at P < 0.05 significance. Hyponatremia was defined as mild (<135 mEq/L), moderate (<130 mEq/L), or severe (<125 mEq/L) based on the lowest postoperative laboratory draw.

RESULTS

Twenty-three patients (10.0%) developed mild postoperative hyponatremia. No patient developed moderate or severe postoperative hyponatremia. On multivariable regression, decreased preoperative sodium level (P = 0.03) and decreased preoperative weight (P = 0.02) were significantly associated with mild postoperative hyponatremia. No patient developed complications or required hospital readmission because of hyponatremia.

CONCLUSIONS

This large retrospective cohort study of patients with nonsyndromic single-suture craniosynostosis demonstrated a 10% prevalence of mild, clinically inconsequential hyponatremia and 0% prevalence of moderate or severe, clinically significant hyponatremia after primary CVR. Patients with low preoperative sodium level or weight were at increased risk for developing mild postoperative hyponatremia. The results suggest that patients with preoperative sodium greater than 140 mEq/L or preoperative weight greater than 10 kg may be candidates for limited postoperative sodium surveillance; however, future prospective studies are warranted before implementation.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Associations between Baseline Hyponatremia and Activities of Daily Living and Muscle Health in Convalescent Stroke Patients

Objectives

Evidence is scarce regarding the association between hyponatremia and functional outcomes among older hospitalized patients. We aimed to evaluate the associations between baseline hyponatremia and improvement in activities of daily living (ADL) and muscle health in hospitalized post-stroke patients.

Methods

This retrospective cohort study included hospitalized post-stroke patients. Serum sodium concentrations were extracted from medical records based on blood tests performed within 24 h of admission, with hyponatremia defined as a serum sodium concentration below135 mEq/L. Primary outcome was the discharge ADL as assessed by the motor domain of the Functional Independence Measure (FIM-motor) and its corresponding gain during hospitalization. Other outcomes encompassed the discharge scores for skeletal muscle mass (SMI) and handgrip strength (HGS). Multivariate linear regression analyses were used to determine the association between hyponatremia and outcomes of interest, adjusted for potential confounders.

Results

Data from 955 patients (mean age 73.2 years; 53.6% men) were analyzed. The median baseline blood sodium level was 139 [interquartile range: 137, 141] mEq/L, and 84 patients (8.8%) exhibited hyponatremia. After full adjustment for confounders, baseline hyponatremia was significantly and negatively associated with FIM-motor at discharge (β=-0.036, P=0.033) and its gain during hospital stay (β=-0.051, P=0.033). Baseline hyponatremia exhibited an independent and negative association with discharge HGS (β=-0.031, P=0.027), whereas no significant association was found between baseline hyponatremia and discharge SMI (β=-0.015, P=0.244).

Conclusions

Baseline hyponatremia demonstrated a correlation with compromised ADL and muscle health in individuals undergoing rehabilitation after stroke.

Hyponatremia, hypernatremia and impairment of functional, psychological and sexual domains

OBJECTIVE

To determine the influence of serum sodium on physical, psychologic and sexual function.

METHODS

This is a cross-sectional survey on 3340 community-dwelling men aged 40-79 years from a prospective cohort study in eight European countries, the European Male Ageing Study (EMAS). Participants filled-out the Short Form-36 (SF-36), the Physical Activity Scale for the Elderly (PASE), and the EMAS sexual function questionnaire. For all the analyses, serum sodium corrected for glycaemia ([Na+]G) was used.

RESULTS

The relationship between [Na+]G and SF-36 physical function score (F = 3.99; p = 0.01), SF-36 mental health score (F = 7.69; p < 0.001), and PASE score (F = 14.95; p < 0.001) were best described by a quadratic equation, with worse scores for [Na+]G in either the lowest or the highest ends of the range. After dividing the sample into [Na+]G < 136 mmol/L (n = 81), 136-147 mmol/L (n = 3223) and > 147 mmol/L (n = 36), linear regression analyses with linear spline functions adjusted for confounders did not confirm these relationships. Similarly, erectile dysfunction and [Na+]G, were in a quadratic relationship (F = 9.00; p < 0.001). After adjusting for confounders, the linear regression with spline functions denoted a significantly worsened erectile function for increases in serum [Na+]G > 147 mmol/L (B = 0.15 [0.04;0.26], p < 0.01) but no relationship with [Na+]G < 136 mmol/L. Likewise, the relationship of [Na+]G with concerns about sexual dysfunction was confirmed only for men with serum [Na+]G > 147 mmol/L.

CONCLUSIONS

This is the first study supporting an association between [Na+]G and sexual function. A worsening of erection and concerns about sexual function were observed for the highest values of [Na+]G, independently of other relevant factors.

[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.

Palatability of two different formulations of urea for the treatment of hyponatremia: A double-blind, randomized, cross-over study

BACKGROUND AND AIMS

Hyponatremia (HN) is the most common disorder of electrolytes encountered in clinical practice. Considering that HN is associated with high morbidity and mortality, it is important to identify treatments for these patients. The therapeutic approaches for HN depend on the severity and the character of the pathology (acute vs. chronic). Among intervention strategies, oral urea represents an effective, safe, and well-tolerated therapeutic approach in the management of chronic hyponatremia. Oral ureal is commonly prepared as a galenic formulation that is usually associated with distaste problems. A double-blind, randomized, cross-over clinical trial was conducted to evaluate and compare the palatability of two different urea formulations: a commercial urea formulation and a galenic one (trial registered on www.isrctn.com, number: ISRCTN18369035).

MATERIALS AND METHODS

Thirty-six healthy subjects (18 female and 18 male, median age 55 years) were enrolled in the study and randomized to consume 7 g of formulation A (commercial formulation) or formulation B (galenic formulation) twice a day away from meals, solubilizing the products in 125 mL of water (T0). After three days of a wash-out, the formulations were crossed-over and consumed twice a day away from meals (T4). After the consumption of products, both in the morning and the evening, participants completed a specific questionnaire to evaluate the products' palatability.

RESULTS

The commercial formulation was globally more appreciated than the galenic one, in terms of smell, taste, and aftertaste. The commercial formulation was better accepted as a potential treatment in 44 % of subjects compared to 14 % of subjects for galenic formulation.

CONCLUSIONS

The clinical trial confirmed the better palatability of the commercial oral urea formulation, containing citrus flavor, which therefore represents a therapeutic strategy that could improve adherence to the therapy in chronic patients with hyponatremia.

Thalamic Neuron Resilience during Osmotic Demyelination Syndrome (ODS) Is Revealed by Primary Cilium Outgrowth and ADP-ribosylation factor-like protein 13B Labeling in Axon Initial Segment

A murine osmotic demyelinating syndrome (ODS) model was developed through chronic hyponatremia, induced by desmopressin subcutaneous implants, followed by precipitous sodium restoration. The thalamic ventral posterolateral (VPL) and ventral posteromedial (VPM) relay nuclei were the most demyelinated regions where neuroglial damage could be evidenced without immune response. This report showed that following chronic hyponatremia, 12 h and 48 h time lapses after rebalancing osmolarity, amid the ODS-degraded outskirts, some resilient neuronal cell bodies built up primary cilium and axon hillock regions that extended into axon initial segments (AIS) where ADP-ribosylation factor-like protein 13B (ARL13B)-immunolabeled rod-like shape content was revealed. These AIS-labeled shaft lengths appeared proportional with the distance of neuronal cell bodies away from the ODS damaged epicenter and time lapses after correction of hyponatremia. Fine structure examination verified these neuron abundant transcriptions and translation regions marked by the ARL13B labeling associated with cell neurotubules and their complex cytoskeletal macromolecular architecture. This necessitated energetic transport to organize and restore those AIS away from the damaged ODS core demyelinated zone in the murine model. These labeled structures could substantiate how thalamic neuron resilience occurred as possible steps of a healing course out of ODS.

Machine learning: Predicting hospital length of stay in patients admitted for lupus flares

BACKGROUND

Although rare, severe systemic lupus erythematosus (SLE) flares requiring hospitalization account for most of the direct costs of SLE care. New machine learning (ML) methods may optimize lupus care by predicting which patients will have a prolonged hospital length of stay (LOS). Our study uses a machine learning approach to predict the LOS in patients admitted for lupus flares and assesses which features prolong LOS.

METHODS

Our study sampled 5831 patients admitted for lupus flares from the National Inpatient Sample Database 2016-2018 and collected 90 demographics and comorbidity features. Four machine learning (ML) models were built (XGBoost, Linear Support Vector Machines, K Nearest Neighbors, and Logistic Regression) to predict LOS, and their performance was evaluated using multiple metrics, including accuracy, receiver operator area under the curve (ROC-AUC), precision-recall area under the curve (PR- AUC), and F1-score. Using the highest-performing model (XGBoost), we assessed the feature importance of our input features using Shapley value explanations (SHAP) to rank their impact on LOS.

RESULTS

Our XGB model performed the best with a ROC-AUC of 0.87, PR-AUC of 0.61, an F1 score of 0.56, and an accuracy of 95%. The features with the most significant impact on the model were "the need for a central line," "acute dialysis," and "acute renal failure." Other top features include those related to renal and infectious comorbidities.

CONCLUSION

Our results were consistent with the established literature and showed promise in ML over traditional methods of predictive analyses, even with rare rheumatic events such as lupus flare hospitalizations.

Syndrome of Inappropriate Antidiuresis: From Pathophysiology to Management

Hyponatremia is the most common electrolyte disorder, affecting more than 15% of patients in the hospital. Syndrome of inappropriate antidiuresis (SIAD) is the most frequent cause of hypotonic hyponatremia, mediated by nonosmotic release of arginine vasopressin (AVP, previously known as antidiuretic hormone), which acts on the renal V2 receptors to promote water retention. There are a variety of underlying causes of SIAD, including malignancy, pulmonary pathology, and central nervous system pathology. In clinical practice, the etiology of hyponatremia is frequently multifactorial and the management approach may need to evolve during treatment of a single episode. It is therefore important to regularly reassess clinical status and biochemistry, while remaining alert to potential underlying etiological factors that may become more apparent during the course of treatment. In the absence of severe symptoms requiring urgent intervention, fluid restriction (FR) is widely endorsed as the first-line treatment for SIAD in current guidelines, but there is considerable controversy regarding second-line therapy in instances where FR is unsuccessful, which occurs in around half of cases. We review the epidemiology, pathophysiology, and differential diagnosis of SIAD, and summarize recent evidence for therapeutic options beyond FR, with a focus on tolvaptan, urea, and sodium-glucose cotransporter 2 inhibitors.

From Crashing Waves to Crashing Sodium: A Rare Case of Nearly Asymptomatic Severe Hyponatremia

Hyponatremia refers to an abnormally low serum sodium level, and it is the most common electrolyte disorder encountered in the clinical setting. Despite its prevalence, hyponatremia can be challenging to clinically identify in some cases due to non-specific symptom presentation. In this case report, we illustrate the rare clinical course of a nearly asymptomatic patient with severe hyponatremia and discuss potential explanations for this uncommon presentation.

Challenge in hyponatremic patients - the potential of a laboratory-based decision support system for hyponatremia to improve patient's safety

OBJECTIVES

Hyponatremia is the most frequent electrolyte disorder in hospitalized patients with increased mortality and morbidity. In this study, we evaluated the follow-up diagnostic, the risk of inadequate fast correction and the outcome of patients with profound hyponatremia (pHN), defined as a blood sodium concentration below 120 mmol/L. The aim was to identify a promising approach for a laboratory-based clinical decision support system (CDSS).

METHODS

This retrospective study included 378,980 blood sodium measurements of 83,315 cases at a German tertiary care hospital. Hospitalized cases with pHN (n=211) were categorized into two groups by the time needed for a follow-up measurement to be performed (time to control, TTC) as either <12 h (group 1: "TTC≤12 h", n=118 cases) or >12 h (group 2: "TTC>12 h", n=93 cases). Length of hospital stay, sodium level at discharge, ward transfers, correction of hyponatremia, and risk of osmotic demyelination syndrome (ODS) due to inadequate fast correction were evaluated with regard to the TTC of sodium blood concentration.

RESULTS

pHN was detected in 1,050 measurements (0.3%) in 211 cases. Cases, in which follow-up diagnostics took longer (TTC>12 h), achieved a significantly lower sodium correction during their hospitalization (11.2 vs. 16.7 mmol/L, p<0.001), were discharged more frequently in hyponatremic states (<135 mmol/L; 58 (62.4%) vs. 43 (36.4%), p<0.001) and at lower sodium blood levels (131.2 vs. 135.0 mmol/L, p<0.001). Furthermore, for these patients there was a trend toward an increased length of hospital stay (13.1 vs. 8.5 days, p=0.089), as well as an increased risk of inadequate fast correction (p<0.001).

CONCLUSIONS

Our study shows that less frequent follow-up sodium measurements in pHN are associated with worse outcomes. Patients with a prolonged TTC are at risk of insufficient correction of hyponatremia, reduced sodium values at discharge, and possible overcorrection. Our results suggest that a CDSS that alerts treating physicians when a control time of >12 h is exceeded could improve patient care in the long term. We are initiating a prospective study to investigate the benefits of our self-invented CDSS (www.ampel.care) for patients with pHN.

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.

Endocrinology specialty service for inpatients: an unmet growing need

BACKGROUND

There is recent concern regarding the documented mismatch between demand and supply, vis-à-vis the growing need for trained endocrinologists unmet by parallel rise in the world workforce of endocrinologist. Due to the increasing complexity of disease in inpatients, in recent years we have experienced a growing demand for inpatient endocrine consults. Surprisingly, the need for the endocrinology subspecialty in the overall care of inpatients in the current setting of general hospitals has received little attention.

METHODS

A retrospective analysis of endocrine consult service based on solicited consults carried out during 3 consecutive months.

RESULTS

During 3 months, there were 767 consults, comprised of 156 diabetes referrals and 611 endocrine/metabolic consult requests. The 611 "non-glucocentric" consult requests were related to 295 inpatients (2.1 ± 2.7 consults/patient). Mean patient age was 58.9 ± .18 years (range 21-92), with some F/M preponderance (58/42%). Requests for endocrine consults were evenly distributed (49.8%, 50.2%) between internal medicine and surgery wards. Case distribution was as follows: thyroid 45.4%, calcium & bone 11.5%, pituitary 12%, adrenal 10% and all others 8.1-0.7%. The mean response time was 4.4 ± 2.7 h. The consults had a discernible effect on the patients' disease management in 60% of the patients. Of these, the consults modified the hospital treatment in 74%, the discharge treatment recommendations in 19% and the diagnosis in 7%.

CONCLUSION

At a large medical center, endocrine consults were requested for ~ 3.3% of all admitted inpatients. The endocrine consults modified pre-consult diagnosis or treatment in ~ 60% of the cases. Contrary to its common image as an exclusively outpatient-based subspecialty, endocrinology practiced by specialists and endocrine trainees has a notable role in the daily care of inpatients admitted to a referral general hospital.

Predictive correction of serum sodium concentration with formulas derived from the Edelman equation in patients with severe hyponatremia

Severe hyponatremia can cause life-threatening cerebral edema. Treatment comprises rapid elevation of serum sodium concentration; however, overcorrection can result in osmotic demyelination. This study investigated potential factors, including predictive correction based on the Edelman equation, associated with appropriate correction in 221 patients with a serum sodium concentration ≤ 120 mEq/L who were admitted to a hospital in Nagoya, Japan. Appropriate correction was defined as an elevation in serum sodium concentration in the range of 4-10 mEq/L in the first 24 h and within 18 mEq/L in the first 48 h after the start of the correction. Appropriate corrections were made in 132 (59.7%) of the 221 patients. Multivariate analysis revealed that predictive correction with an infusate and fluid loss formula derived from the Edelman equation was associated with appropriate correction of serum sodium concentration (adjusted odds ratio, 7.84; 95% confidence interval, 2.97-20.64). Relative without its use, the predictive equation results in a lower proportion of undercorrection (14.3% vs. 48.0%, respectively) and overcorrection (1.0% vs. 12.2%, respectively). These results suggest that predictive correction of serum sodium concentrations using the formula derived from the Edelman equation can play an essential role in the appropriate management of patients with severe hyponatremia.

Association of hypernatremia with outcomes of COVID-19 patients: A protocol for systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to assess the association of hypernatremia with the outcomes of COVID-19 patients.

METHODS

We performed a systematic literature search on PubMed, Google Scholar, and Science Direct until October 2021 and found a total of 131 papers. With meticulous screening finally, 17 papers met the inclusion criteria. COVID-19 patients with sodium levels greater than the reference level were the study population and the outcome of interest was the poor outcome; such as mortality, mechanical ventilation, intensive care unit (ICU) admission, and prolonged hospital stay. The pooled estimate was calculated as the odds ratio (OR).

RESULTS

There were 19,032 patients with hypernatremia in the 17 studies included. An overall random effect meta-analysis showed that hypernatremia was associated with mortality (OR: 3.18 [1.61, 6.28], P < .0001, I2 = 91.99%), prolong hospitalization (OR: 1.97 [1.37, 2.83], P < .001, I2 = 0.00%) and Ventilation (OR: 5.40 [1.89, 15.42], P < .001, I2 = 77.35%), ICU admission (OR: 3.99 [0.89, 17.78], P = .07, I2 = 86.79%). Meta-regression analysis showed the association of age with the ICU outcome of hypernatremia patients. Whereas, other parameters like male, hypertension, chronic kidney disease, and diabetes mellitus did not significantly influence the odds ratio.

CONCLUSION

Hypernatremia was markedly associated with poor outcomes in patients with COVID-19. Hence, a blood ionogram is warranted and special attention must be given to hypernatremia COVID-19 patients.

Approach to the Patient: Hyponatremia and the Syndrome of Inappropriate Antidiuresis (SIAD)

Hyponatremia is the most common electrolyte disturbance seen in clinical practice, affecting up to 30% of acute hospital admissions, and is associated with significant adverse clinical outcomes. Acute or severe symptomatic hyponatremia carries a high risk of neurological morbidity and mortality. In contrast, chronic hyponatremia is associated with significant morbidity including increased risk of falls, osteoporosis, fractures, gait instability, and cognitive decline; prolonged hospital admissions; and etiology-specific increase in mortality. In this Approach to the Patient, we review and compare the current recommendations, guidelines, and literature for diagnosis and treatment options for both acute and chronic hyponatremia, illustrated by 2 case studies. Particular focus is concentrated on the diagnosis and management of the syndrome of inappropriate antidiuresis. An understanding of the pathophysiology of hyponatremia, along with a synthesis of the duration of hyponatremia, biochemical severity, symptomatology, and blood volume status, forms the structure to guide the appropriate and timely management of hyponatremia. We present 2 illustrative cases that represent common presentations with hyponatremia and discuss the approach to management of these and other causes of hyponatremia.

Using Tolvaptan to Treat Hyponatremia: Results from a Post-authorization Pharmacovigilance Study

Introduction

Hyponatremia is a common condition of varying etiology among hospitalized patients and is associated with adverse outcomes. Treatment to normalize serum sodium is advisable. Tolvaptan received European Union marketing authorization for hyponatremia secondary to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Post-marketing pharmacovigilance activities were required to characterize the safety profile of tolvaptan more fully in this population, which is often elderly with a high burden of comorbid illness.

Methods

This was a prospective, observational, multinational, post-authorization pharmacovigilance study (NCT01228682) in seven European countries. Hospitalized patients were enrolled who received tolvaptan for hyponatremia associated with SIADH and consented to data collection. Tolvaptan was initiated and assessments performed at physician discretion per local standards of care. To reflect actual clinical practice, no assessments or procedures were required outside the standard of care. Patients who continued to receive long-term tolvaptan following hospital discharge and provided consent received follow-up from their community physicians.

Results

A total of 252 patients (mean age 70.6 years) enrolled. Mean tolvaptan treatment duration was 139.4 days, median 18.5 (range 1–1130) days; most frequent dose was 15 mg/day (used in 75% of patients). Serum sodium increased from baseline (mean 123.2 mmol/l) during treatment week 1 and remained stable during follow-up, with little difference across doses of 7.5, 15, and 30 mg/day. Hyponatremia symptoms (e.g., confusion, unsteady gait, lethargy) were present in 122/252 (48.4%) patients at pre-treatment baseline, decreasing to 46/252 (18.3%) during treatment. Sixty-two patients (24.6%; mean baseline serum sodium 120 mmol/l) experienced rapid correction of hyponatremia within 72 h. No osmotic demyelination syndrome occurred.

Conclusion

In clinical practice, tolvaptan improved serum sodium and decreased hyponatremia symptoms in hyponatremia secondary to SIADH. Serum sodium should be monitored during treatment to minimize risk of rapid correction.

Trial Registration

Clinicaltrials.gov identifier NCT01228682.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01947-9.

Hospitalized patients often experience abnormally low blood sodium levels (hyponatremia), which can cause significant symptoms and poses a serious health risk (Wald et al. in Arch Intern Med 170:294–302, 2010). Yet, increasing sodium levels too rapidly in these patients can unintentionally cause osmotic demyelination syndrome, resulting in long-term neurologic damage or death. Tolvaptan was approved in the European Union to treat one type of hyponatremia caused by a hormonal imbalance known as the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Tolvaptan effectively increased patient sodium levels in clinical trials, but real-world data are needed to understand tolvaptan treatment more fully in everyday clinical practice. We evaluated patterns of use, efficacy, and safety of tolvaptan in patients treated in hospitals and after discharge for hyponatremia due to SIADH. Tolvaptan was correctly used to treat only hyponatremia caused by SIADH in nearly all of the 252 patients studied. Patient sodium levels increased in the first week of tolvaptan treatment and then stabilized. Hyponatremia symptoms, such as confusion, nausea, tiredness, and dizziness, were present in 48.4% of patients before treatment and in 18.3% after starting tolvaptan. Consistent with earlier studies, some patients (24.6%) experienced excessively rapid correction of hyponatremia. However, no subsequent neurologic problems or deaths were attributed to the rapid correction, which suggests that medical providers were carefully monitoring and managing sodium levels to prevent serious consequences. Our study indicates that tolvaptan is being used safely and effectively to treat hyponatremia due to SIADH in a patient population with complex medical needs.

Acute Water Intoxication With Resultant Hypo-Osmolar Hyponatremia Complicated by Hypotension Secondary to Diffuse Third-Spacing

Hypotonic hyponatremia secondary to acute water intoxication is most commonly associated with primary polydipsia in the setting of psychiatric illness. However, in certain circumstances, otherwise healthy individuals can be compelled to consume large enough volumes of water to overwhelm the kidney’s dilutional capacity of urine and cause a potentially life-threatening rapid decline in serum sodium. We present such a case of a 20-year-old basic military trainee with acute symptomatic hypotonic hyponatremia after drinking five to six liters of water prior to urine drug testing. The clinical manifestations of this disorder are non-specific and can be seen with many different pathologic processes, presenting a diagnostic challenge to the emergency clinician. This challenge can be further complicated by unclear or unobtainable history depending on clinical presentation. The authors will discuss key diagnostic and treatment elements of this potentially life-threatening disease to encourage clinicians to utilize social history when evaluating cases of acute water intoxication and resultant symptomatic hypotonic hyponatremia. 

Disorders of sodium balance in COVID-19 patients: two Tunisian patients report

Coronavirus disease 2019 (COVID-19) was first reported in December 2019. The disease is caused by severe acute respiratory syndrome virus corona virus 2 (SARS-CoV-2). Mild respiratory symptoms are the most common manifestations of SARS-CoV-2, but new signs are constantly being discovered as it spreads. Disorders of sodium balance are increasingly described in patients with SARS-CoV-2. We report, here, the cases of two patients presented with COVID-19 and in whom we discovered sodium disorders. The first patient is a 74-year-old man who presented with fatal hypernatremia. The second patient is a 66-years-old man presented with COVID-19 and euvolemic hyponatremia attributed to syndrome of inappropriate anti-diuretic hormone secretion (SIADH). This hyponatremia persisted long after the respiratory signs disappeared. Sodium balance disorders are increasingly described in the literature; special attention should be paid to the electrolyte status of COVID-19 patients. Pathophysiological mechanisms associating SARS-CoV-2 with these disorders are being studied.

Syndrome of Inappropriate Antidiuretic Hormone Secretion-Induced Encephalopathy in a Patient With COVID-19

Various electrolyte imbalances have been documented in coronavirus disease 2019 (COVID-19) patients who progress to severe acute respiratory syndrome coronavirus-2 infection. Patients with co-morbidities like diabetes, hypertension, obesity, ischemic heart disease, chronic kidney disease, and chronic obstructive pulmonary disease are more vulnerable to developing complications in the form of electrolyte disturbance.

We report a case of acute severe hyponatremia in a middle-aged man who was admitted to the hospital with viral pneumonia due to a coronavirus-2 infection. A dramatic drop of plasma sodium was preceded by gastrointestinal symptoms and followed by encephalopathy. On clinical assessment his plasma sodium was found to be critically low, i.e. 105 mmol/L. His chest x-ray showed minimal pleural effusion.

The patient was managed in the ICU and his serum sodium was normalized gradually with partial but rapid correction of this severe hyponatremia with hypertonic sodium chloride and followed by fluid restriction.

Non-thiazide diuretics and hospitalization due to hyponatraemia: A population-based case-control study

OBJECTIVE

Diuretics are often implicated in hyponatraemia. While thiazides constitute one of the most common causes of hyponatraemia, data on loop diuretics and potassium-sparing agents are limited and partly conflicting. The objective of this investigation was to study the association between use of different types of non-thiazide diuretics and hospitalization due to hyponatraemia.

DESIGN, PATIENTS AND MEASUREMENTS

This was a register-based case-control study on the adult Swedish population. By linking national registers, patients hospitalized with a principal diagnosis of hyponatraemia (n = 11,213) from 1 October 2005 through 31 December 2014 were compared with matched controls (n = 44,801). Multivariable logistic regression, adjusted for multiple confounders, was used to analyse the association between use of diuretics and hyponatraemia. In addition, newly initiated use (≤90 days) and ongoing use were examined separately.

RESULTS

Adjusted odds ratios (aORs) (95% CI) were 0.61 (0.57-0.66) for the use of furosemide, 1.69 (1.54-1.86) for the use of amiloride and 1.96 (1.78-2.18) for the use of spironolactone and hospitalization due to hyponatraemia. For newly initiated therapy, aORs ranged from 1.23 (1.04-1.47) for furosemide to 3.55 (2.75-4.61) for spironolactone. The aORs for ongoing use were 0.52 (0.47-0.57) for furosemide, 1.62 (1.47-1.79) for amiloride and 1.75 (1.56-1.98) for spironolactone.

CONCLUSIONS

Ongoing use of furosemide was inversely correlated with hospitalization due to hyponatraemia, suggesting a protective effect. Consequently, if treatment with furosemide precedes the development of hyponatraemia by some time, other causes of hyponatraemia should be sought. Spironolactone and amiloride may both contribute to hyponatraemia; this effect is most prominent early in treatment.

Association of Pre-ESKD Hyponatremia with Post-ESKD Outcomes among Incident ESKD Patients

BACKGROUND

Hyponatremia is one of the most common electrolyte disturbances in advanced chronic kidney disease (CKD) and end-stage kidney disease (ESKD) patients and has been shown to be associated with higher mortality risk. However, the relationship between hyponatremia during late-stage CKD and the risk of poor outcomes after ESKD transition is unknown.

METHODS

We conducted a retrospective cohort study including 32,257 US veterans transitioning to ESKD from October 1, 2007 to March 30, 2015. We evaluated adjusted associations between the 3-month averaged pre-transition to ESKD serum sodium and all-cause mortality. Secondary outcomes included cardiovascular (CV) mortality, infection-related mortalities, and hospitalization rate.

RESULTS

Cohort mean±SD serum sodium was 139 ± 3 mEq/L, mean age was 67 ± 11 years, 98% were male, and 32% were African American. Over a median follow-up of 702 days (296, 1301) there were 17,162 deaths. Compared to the reference of 135-<144 mEq/L, the lowest serum sodium group (<130 mEq/L) had a 54% higher all-cause mortality risk (hazard ratio [HR]: 1.54, 95% confidence interval [CI]: 1.34, 1.76) in the fully adjusted model. Associations were similar for CV and infection-related mortality, and hospitalization outcomes.

CONCLUSIONS

Hyponatremia prior to ESKD transition is associated with higher risk of all-cause, CV, and infection-related mortalities and hospitalization rates after ESKD transition. Future studies evaluating management of pre-ESKD hyponatremia may be indicated to improve patient outcomes for those transitioning to ESKD.

Serum sodium alterations in SARS CoV-2 (COVID-19) infection: impact on patient outcome

OBJECTIVE

Hyponatremia is the most common electrolyte disorder in hospitalized patients and occurs in about 30% of patients with pneumonia. Hyponatremia has been associated with a worse outcome in several pathologic conditions The main objective of this study was to determine whether serum sodium alterations may be independent predictors of the outcome of hospitalized COVID-19 patients.

DESIGN AND METHODS

In this observational study, data from 441 laboratory-confirmed COVID-19 patients admitted to a University Hospital were collected. After excluding 61 patients (no serum sodium at admission available, saline solution infusion before sodium assessment, transfer from another hospital), data from 380 patients were analyzed.

RESULTS

274 (72.1%) patients had normonatremia at admission, 87 (22.9%) patients had hyponatremia and 19 (5%) patients had hypernatremia. We found an inverse correlation between serum sodium and IL-6, whereas a direct correlation between serum sodium and PaO2/FiO2 ratio was observed. Patients with hyponatremia had a higher prevalence of non-invasive ventilation and ICU transfer than those with normonatremia or hypernatremia. Hyponatremia was an independent predictor of in-hospital mortality (2.7-fold increase vs normonatremia) and each mEq/L of serum sodium reduction was associated with a 14.4% increased risk of death.

CONCLUSIONS

These results suggest that serum sodium at admission may be considered as an early prognostic marker of disease severity in hospitalized COVID-19 patients.

Hyponatremia is a Prognostic Factor in Patients Receiving Nutrition Support

BACKGROUND

Hyponatremia, the most common electrolyte disorder, has been reported to be related to increased mortality. However, the association between hyponatremia and prognoses remains unclear in patients with nutrition support team (NST) intervention. This study aimed to determine the prevalence of abnormal serum sodium levels, its relation to patient data, and the impact of hyponatremia on prognosis.

METHODS

Patients who received nutrition support at Tokushima University Hospital for the first time and whose serum sodium levels were measured at the start of NST intervention were enrolled. Patients were classified into three groups according to their serum Na levels at the start of NST intervention: hyponatremia group, normonatremia group, and hypernatremia group.

RESULTS

In the hyponatremia group compared to the normonatremia group, body weight and body mass index were significantly lower. C-reactive protein levels and urea nitrogen/creatinine ratios were significantly higher. Meanwhile, there was no significant difference in the estimated glomerular filtration rate among the groups. The prevalence of malnutrition and anemia were the highest in the hyponatremia group. The 3-year survival rate was approximately 45% in the hyponatremia group, which was the lowest of all three groups. The mortality risk ratio of the hyponatremia group to the normonatremia group was 2.29.

CONCLUSIONS

Hyponatremia in NST intervention patients is an independent prognostic predictor. Therefore, adding an assessment of serum sodium at the beginning of NST intervention can identify patients at high risk at an early stage and may improve the quality of NST activity.

Prevalence and outcome of dysnatremia in patients with COVID-19 compared to controls

OBJECTIVE

The pandemic of coronavirus disease (COVID-19) has rapidly spread globally and infected millions of people. The prevalence and prognostic impact of dysnatremia in COVID-19 is inconclusive. Therefore, we investigated the prevalence and outcome of dysnatremia in COVID-19.

DESIGN

The prospective, observational, cohort study included consecutive patients with clinical suspicion of COVID-19 triaged to a Swiss Emergency Department between March and July 2020.

METHODS

Collected data included clinical, laboratory and disease severity scoring parameters on admission. COVID-19 cases were identified based on a positive nasopharyngeal swab test for SARS-CoV-2, patients with a negative swab test served as controls. The primary analysis was to assess the prognostic impact of dysnatremia on 30-day mortality using a cox proportional hazard model.

RESULTS

172 (17%) cases with COVID-19 and 849 (83%) controls were included. Patients with COVID-19 showed a higher prevalence of hyponatremia compared to controls (28.1% vs 17.5%, P < 0.001); while comparable for hypernatremia (2.9% vs 2.1%, P = 0.34). In COVID-19 but not in controls, hyponatremia was associated with a higher 30-day mortality (HR: 1.4, 95% CI: 1.10-16.62, P = 0.05). In both groups, hypernatremia on admission was associated with higher 30-day mortality (COVID-19 - HR: 11.5, 95% CI: 5.00-26.43, P < 0.001; controls - HR: 5.3, 95% CI: 1.60-17.64, P = 0.006). In both groups, hyponatremia and hypernatremia were significantly associated with adverse outcome, for example, intensive care unit admission, longer hospitalization and mechanical ventilation.

CONCLUSION

Our results underline the importance of dysnatremia as predictive marker in COVID-19. Treating physicians should be aware of appropriate treatment measures to be taken for patients with COVID-19 and dysnatremia.

Risk of Adverse Clinical Outcomes in Hyponatremic Adult Patients Hospitalized for Acute Medical Conditions: A Population-Based Cohort Study

CONTEXT

Hyponatremia has been associated with excess long-term morbidity and mortality. However, effects during hospitalization are poorly studied.

OBJECTIVE

The objective of this work is to examine the association of hyponatremia with the risk of in-hospital mortality, 30-day readmission, and other short-term adverse events among medical inpatients.

DESIGN AND SETTING

A population-based cohort study was conducted using a Swiss claims database of medical inpatients from January 2012 to December 2017.

PATIENTS

Hyponatremic patients were 1:1 propensity-score matched with normonatremic medical inpatients.

MAIN OUTCOME MEASURE

The primary outcome was a composite of all-cause in-hospital mortality and 30-day hospital readmission. Secondary outcomes were intensive care unit (ICU) admission, intubation rate, length-of-hospital stay (LOS), and patient disposition after discharge.

RESULTS

After matching, 94 352 patients were included in the cohort. Among 47 176 patients with hyponatremia, 8383 (17.8%) reached the primary outcome compared with 7994 (17.0%) in the matched control group (odds ratio [OR] 1.06 [95% CI, 1.02-1.10], P = .001). Hyponatremic patients were more likely to be admitted to the ICU (OR 1.43 [95% CI, 1.37-1.50], P < .001), faced a 56% increase in prolonged LOS (95% CI, 1.52-1.60, P < .001), and were admitted more often to a postacute care facility (OR 1.38 [95% CI 1.34-1.42, P < .001). Of note, patients with the syndrome of inappropriate antidiuresis (SIAD) had lower in-hospital mortality (OR 0.67 [95% CI, 0.56-0.80], P < .001) as compared with matched normonatremic controls.

CONCLUSION

In this study, hyponatremia was associated with increased risk of short-term adverse events, primarily driven by higher readmission rates, which was consistent among all outcomes except for decreased in-hospital mortality in SIAD patients.

Anticancer Medications and Sodium Dysmetabolism

Therapeutic advances have revolutionised cancer treatment over the last two decades, but despite improved survival and outcomes, adverse effects to anticancer therapy such as dyselectrolytaemias do occur and need to be managed appropriately. This review explores essential aspects of sodium homeostasis in cancer with a focus on alterations arising from anticancer medications. Sodium and water balance are tightly regulated by close interplay of stimuli arising from hypothalamic osmoreceptors, arterial and atrial baroreceptors and the renal juxtaglomerular apparatus. This delicate balance can be disrupted by cancer itself, as well as the medications used to treat it. Some of the conventional chemotherapeutics, such as alkylating agents and platinum-based drugs, can cause hyponatraemia and, on rare occasions, hypernatraemia. Other conventional agents such as vinca alkaloids, as well as newer targeted cancer therapies including small molecule inhibitors and monoclonal antibodies, can cause hyponatraemia, usually as a result of inappropriate antidiuretic hormone secretion. Hyponatraemia can also sometimes occur secondarily to drug-induced hypocortisolism or salt-wasting syndromes. Another atypical but distinct mechanism for hyponatraemia is via pituitary dysfunction induced by immune checkpoint inhibitors. Hypernatraemia is uncommon and occasionally ensues as a result of drug-induced nephrogenic diabetes insipidus. Identification of the aetiology and appropriate management of these conditions, in addition to averting treatment-related problems, can be lifesaving in critical situations.

Predictors of hyponatremia following elective primary unilateral knee arthroplasty at a tertiary centre: A retrospective observational cohort and predictive model

Introduction

Hyponatremia is a common electrolyte disorder. This can be associated with nausea, disorientation and in more serious cases a decreased level of consciousness or neurological deficits. These symptoms may lead to increases in the cost of hospital care and significant morbidity. The purpose of this retrospective, observational cohort study is to investigate the impact of hyponatremia on patient and systems specific outcome measures in those undergoing elective, unilateral total knee arthroplasty (TKA) at two hospitals in Auckland, New Zealand over a twelve-month period.

Materials and methods

Patients were stratified into two groups based on the presence or absence of post-operative hyponatremia (defined as a blood sodium of <135 mmol/L with a concurrent decrease of ≥5 mmol/L between the pre- and post-operative recordings). Outcomes collected included Quality of Recovery - 15 (QOR) scores, time to assisted mobilisation, discharge ICD-10 complication codes and hospital length of stay.

Results

During the study period 236 patients underwent surgery. Eighty-six (36.4%) patients met criteria for post-operative hyponatremia. This finding was associated with prolongation of the hospital length of stay (4.17 (3.26-5.18) versus 4.28 (3.31-5.45) days, p = 0.031) and a reduction in the QOR score on the second post-operative day (113.0 (99.5-126.5) versus 105.0 (94.0-118.0), p = 0.039). There was no difference in the time to assisted mobilisation.

Conclusions

Hyponatremia is a common finding following TKA. This abnormality is associated with small changes in patient specific outcome measures. These implications of these findings may become more significant in settings where same day or rapid discharge from hospital is targeted.

Prevalence and Description of Hyponatremia in a Swiss Tertiary Care Hospital: An Observational Retrospective Study

Background: Hyponatremia (serum sodium concentration <135 mEq/L) is the most common electrolyte abnormality among hospitalized patients. Our aim was to study the epidemiology of hyponatremia in hospitalized patients, as well as the short-term mortality rates, the length of stay (LOS), and associated hospital costs.

Methods: This retrospective cohort study included 6,539 hospitalizations in the internal medicine ward of a Swiss tertiary-care teaching hospital between January 1, 2012, and December 31, 2018 (42.7% women, mean age 69 years). Using serum sodium concentration, we identified hospitalizations with hyponatremia and calculated the prevalence of overall hyponatremia, admission hyponatremia (AH), hospital-acquired hyponatremia (HAH), and persistent hyponatremia (PH) at discharge. We also studied the impact of hyponatremia on 30-day readmissions, in-hospital and 30-day mortality, and hospital LOS and costs, using multivariable logistic regression and Cox proportional hazards models, with normal natremia as reference.

Results: Prevalence of overall hyponatremia was 32.5% [95% confidence interval (CI), 31.3–33.6%], while prevalence of PH among hospitalizations with AH and HAH was 33.7% (31.7–35.8%). After multivariable adjustment, hyponatremia was associated with increased hospital costs (CHF 19,025 ± 485 vs. 14,962 ± 341, p < 0.001) and LOS (13.4 ± 0.2 vs. 10.7 ± 0.2 days, p < 0.001). Increased severity of hyponatremia was associated with higher hospital costs and LOS (p for trend <0.001). There was a trend toward more frequent 30-day readmissions associated with hyponatremia [adjusted odds ratio (OR), 1.15 (1.01–1.31), p = 0.032], mainly with PH: adjusted OR = 1.41 (1.17–1.71), p < 0.001. No association was found between severity of hyponatremia and readmissions. Hyponatremia was associated with an increase of in-hospital [adjusted OR = 1.94 (1.49–2.53), p < 0.001] and 30-day mortality: adjusted OR = 1.80 (1.44–2.24), p < 0.001. Increased severity of hyponatremia was associated with higher in-hospital and 30-day mortality (p for trend < 0.001).

Conclusions: Hyponatremia is highly prevalent among hospitalized patients and associated with an increase of LOS, early hospital readmission, in-hospital and 30-day mortality, and hospital costs. PH was associated with a substantial increase of the risk of early hospital readmission and 30-day mortality.

Are Further Interventions Needed to Prevent and Manage Hospital-Acquired Hyponatraemia? A Nationwide Cross-Sectional Survey of IV Fluid Prescribing Practices

BACKGROUND

Hyponatraemia is associated with increased morbidity, increased mortality and is frequently hospital-acquired due to inappropriate administration of hypotonic fluids. Despite several attempts to minimise the risk, knowledge is lacking as to whether inappropriate prescribing practice continues to be a concern.

METHODS

A cross-sectional survey was performed in Danish emergency department physicians in spring 2019. Prescribing practices were assessed by means of four clinical scenarios commonly encountered in the emergency department. Thirteen multiple-choice questions were used to measure knowledge.

RESULTS

201 physicians responded corresponding to 55.4% of the total population of physicians working at emergency departments in Denmark. About a quarter reported that they would use hypotonic fluids in patients with increased intracranial pressure and 29.4% would use hypotonic maintenance fluids in children, both of which are against guideline recommendations. Also, 29.4% selected the correct fluid, a 3% hypertonic saline solution, for a patient with hyponatraemia and severe neurological symptoms, which is a medical emergency. Most physicians were unaware of the impact of hypotonic fluids on plasma sodium in acutely ill patients.

CONCLUSION

Inappropriate prescribing practices and limited knowledge of a large number of physicians calls for further interventions to minimise the risk of hospital-acquired hyponatraemia.

Hyponatremia: A possible immuno-neuroendocrine interface with COVID-19 in a kidney transplant recipient

There is fast-emerging, cumulative clinical data on coronavirus disease 2019 (COVID-19) in kidney transplant recipients. Although respiratory tract symptoms are often the initial presentation among kidney transplant recipients who contract COVID-19, other clinical features which may indicate underlying SARS-CoV-2-related inflammation, such as gastrointestinal symptoms, are not uncommon. Hyponatremia can develop and may reflect underlying inflammation. Interferon-6 is an important pro-inflammatory cytokine involved in the pathogenesis of severe COVID-19 complications and may play a role in the inappropriately higher secretion of antidiuretic hormone leading to hyponatremia. This pathway is the so-called immuno-neuroendocrine interface. Hyponatremia in COVID-19 has been reported in a few case series of non-kidney transplant patients and only one reported kidney transplant recipient. However, the clinical course and prognostic value of hyponatremia in this population are not described in detail. We report a kidney transplant recipient who was infected with COVID-19 and exhibited severe hyponatremia secondary to the syndrome of inappropriate antidiuretic hormone secretion. Hyponatremia is one of the clinical presentations of COVID-19, although less common, and may occur more frequently in kidney transplant recipients. Thus, the possible underlying immuno-neuroendocrine relationship related to the inflammatory process of COVID-19 leading to hyponatremia and its prognostic value are reviewed.

Tolvaptan therapy to treat severe hyponatremia in pediatric nephrotic syndrome

BACKGROUND

Tolvaptan is a selective oral vasopressin V2-receptor antagonist. Some data have implicated stimulation of arginine vasopressin (AVP) as an important factor in oedema formation in a rodent model of nephrotic syndrome (NS) and adult NS patients. We report case of pediatric NS with severe hyponatremia efficiently treated by tolvaptan.

CASE/DIAGNOSIS - TREATMENT

A 22-month-old girl presented first with NS. She remained nephrotic after a 30-day course of oral steroids. Tacrolimus was inefficient and there was no response to plasma exchanges (15 sessions on a daily basis). She had severe oedema and ascites. Thus, in addition to immunosuppressive therapy, she received diuretics, furosemide 5 mg/kg/day, and amiloride 1 mg/kg/day, and required water restriction. She was hypertensive and was treated with a full dose of calcium inhibitor (amlodipine 0.5 mg/kg/day). After2 months of treatment, serum sodium reached 116 mmol/L and urinary osmolarity 547 mosmol/L, suggesting an inappropriate AVP secretion. Tolvaptan was introduced at 0.3 mg/kg/day and progressively increased to 3 mg/kg/day on day 4, leading to a partial correction of serum sodium (130 mmol/l) and a urinary osmolarity decrease to 90 mosmol/L. Tolvaptan was then continued at the dose of 3 mg/kg/day with unchanged serum sodium, without hypernatremia or dehydration. Her weight decreased from 14.8 k to 14 k, but oedema still persisted.

CONCLUSION

Tolvaptan was very efficient in this case of hyponatremia associated with steroid-resistant NS. Tolvaptan should be considered in the management of therapy-resistant hyponatremia in patients with NS.

Prevalence of hyponatremia among older inpatients in a general hospital

PURPOSE

This study aimed to explore the incidence, clinical features, etiology, and mortality of hyponatremia in older inpatients and thus provide preliminary data for an epidemiological study.

METHODS

Hospitalized older patients diagnosed with hyponatremia at the First Medical Center of PLA General Hospital during January 2013-December 2016 were stratified by serum sodium concentrations into mild (130- < 135 mmol/L), moderate (125- < 130 mmol/L) and severe hyponatremia groups (< 125 mmol/L). Etiologies, medication histories, hospitalization times, and outcomes were analyzed.

RESULTS

During the indicated period, 4364 older patients with hyponatremia were hospitalized, including 2934 men and 1430 women with an average age of 84.6 ± 3.5 years (range 80-104 years). The prevalence of hyponatremia was 24.7%. An analysis of common primary diseases identified respiratory diseases as the most frequent (25.0%), followed by tumors (23.1%), cardiovascular diseases (19.9%), central nervous system diseases (8.9%), and orthopedic diseases (6.1%). PPIs (59.7%), loop diuretics (57.4%), potassium-preserving diuretics (29.5%), ACEIs/ARBs (20.0%), thiazide diuretics (12.5%), and NSAIDs (12.4%) were the drugs most commonly associated with hyponatremia. The in-hospital mortality rate was 11.7%. Aggravated hyponatremia led to a prolonged hospitalization time. Moreover, when compared with mild hyponatremia, moderate and severe hyponatremia were associated with significant increases in in-hospital mortality (ORs 1.89 and 2.66, respectively; 95% CIs 1.54-2.33 and 2.06-3.43, respectively; P < 0.01).

CONCLUSIONS

Hyponatremia is a common complication in hospitalized older patients and is caused mainly by respiratory diseases, tumors, and cardiovascular diseases. Given the correlation between the degree of hyponatremia and prognosis, the early and accurate identification and treatment of this condition can reduce the associated morbidity and mortality.

Mild to moderate hyponatremia at discharge is associated with increased risk of recurrence in patients with community-acquired pneumonia

BACKGROUND

Hyponatremia is the most common electrolyte disorder in hospitalized patients with pneumonia. Different studies have shown an association of hyponatremia on admission and worse patient's outcome. Yet, the impact of hyponatremia at discharge or of hyponatremia correction on patient's prognosis is unknown.

METHODS

This is a preplanned secondary data analysis from a double-blind, randomized, placebo-controlled trial of hospitalized patients with community-acquired pneumonia and prednisone treatment. The primary outcome was the impact of hyponatremia on admission and at discharge on patient relevant outcomes (i.e. mortality, rehospitalization and recurrence rate) within 180 days.

RESULTS

Of the 708 included patients, 185 (26.1%) were hyponatremic on admission. Of these, 28 (15.1%) were still hyponatremic at discharge. 34 (4.8%) patients developed hyponatremia during hospitalization despite being normonatremic on admission. Patients with hyponatremia at discharge had a higher rate of pneumonia recurrence as compared to normonatremic patients (OR 2.68; 95%-CI 1.09-6.95; p = 0.037). Among patients with hyponatremia at discharge, patients who were already hyponatremic on admission showed the strongest association with increased recurrence rate (OR 4.01; 95%-CI 1.08-12.64; p = 0.022). In contrast, recurrence rate was not affected in patients who were hyponatremic on admission but had normalized serum sodium levels at discharge (p = 0.73).

CONCLUSION

Mild to moderate hyponatremia at discharge is associated with an increased risk of recurrence in hospitalized patients with pneumonia. This association is particularly strong for patients who are hyponatremic both on admission and at discharge, emphasizing the importance of hyponatremia correction during hospitalization.

Hyponatremia as an Inflammatory Marker of Lupus Activity Is a Fact or Fad: A Cross-Sectional Study

Purpose

Systemic lupus erythematosus (SLE) is an autoimmune disease with multi-organ involvement. Hyponatremia is common in inflammatory diseases such as meningitis. Also, it has been found to be strongly associated with the degree of inflammation. However, it has not been fully evaluated in lupus. This study aimed to assess the inflammatory impact of hyponatremia in SLE patients and investigate its relationship with SLE disease activity.

Patients and Methods

A total of 101 patients with SLE were enrolled in this study and divided into two groups according to Na level; a normo-natremic group and a hyponatremic group. Demographic and clinical data were collected. SLE activity was assessed by the systemic lupus erythematosus disease activity index (SLEDAI). The estimated sedimentation rate (ESR) as well as levels of C-reactive protein (CRP) and complements (C3 and C4) were measured.

Results

The majority of patients were females (98 subjects) (97%) with a mean age of 33±8 years. Out of 101 participants, 40 patients (39.6%) were hyponatremic with a mean Na level of 131.58±3.11 mmol/L. There was a statistically negative correlation between both ESR and SLEADI score and Na level (r=-0.436 and -0.436, respectively) with p=0.002, whereas Na level was positively correlated with complements, Cl, and albumin levels (r=0.653, 0.314, and 0.460, respectively) (p=0.000, 0.027, and >0.001, respectively). CRP was not correlated with Na level. ESR was independently correlated with hyponatremia at the 95% CI for Exp B (0.997-0.058) with a p-value of 0.048.

Conclusion

Hyponatremia could be used as an indicator of SLE activity. Also, it might be an easily and rapidly detected as well as a prognostically useful marker of inflammation.

Clinical profile of patients with hyponatremia in a tertiary care hospital in the sub-Himalayan region

Introduction:

Hyponatremia, defined as a serum sodium concentration ([Na+]) <135 mEq/L. It is not a disease but rather a pathophysiologic process indicating disturbed water homeostasis. Hyponatremia should be further classified to provide directions for diagnosis and treatment. It is a heterogeneous disorder. The classifications of hyponatremia are commonly based on tonicity and volume status. The initial differentiation in hypotonic and non-hypotonic hyponatremia is important because management is different. Several studies have been conducted previously to measure the incidence of hyponatremia in medically ill patients. Several studies have demonstrated an increased prevalence of hyponatremia in the presence of co-morbid conditions. We conducted this study to bring out various causes of hyponatremia; their relation with sex, age and outcome and hyponatremia's classification and incidence in our hospitalised population.

Materials and Methods:

This study was conducted to find out etiology, classification, prevalence and outcome and its relation with age and sex in patients of hyponatremia admitted in our institution. A total number of 106 patients were studied.

Results:

Hospital-based incidence of hyponatremia was found to be 1.17%. Mean age of patients in study was 62.25 ± 17.7 years. Male to female ratio was 1.25:1. Altered sensorium was the most common neurological symptom. Ninety-five (90%) patients were hypo-osmolar. Out of ninety four patients, 38 (40%) were euvolemic. Chronic obstructive pulmonary disorder (COPD) with cor pulmonale with right-sided heart failure (n = 9, 31%) was the most common cause in hyper-volemic hyponatremia. Acute gastroenteritis (n = 13, 48%) was the most common cause in hypo-volemic hyponatremia. Syndrome of inappropriate anti-diuretic hormone secretion (SIADH) was the most common cause (n = 20, 53%) of euvolemic hyponatremia. Out of 106 patients, 11 (10.38%) patients expired.

Conclusion:

Hyponatremia acts as a poor prognostic marker of the primary disease. It is important to recognise it early because of the potential morbidity and mortality, economic impact on the patients and health care associated with it. Early management of hyponatremia, which includes determination of the rate of correction, the appropriate interventions and the presence of other underlying disorders, may help in improving the outcome and shortening the hospital stay of the patients.

Transient seizure-induced sodium increase camouflaging a symptomatic hyponatremia

Hyponatremia is the most commonly observed electrolyte disturbance in clinical medicine. Occasionally the initial presentation of a patient with a symptomatic hyponatremia is a seizure or coma. This life-threatening complication needs early diagnosis and immediate treatment. Here, we report a case of a 27-year-old man who presented with an epileptic seizure, lactate acidosis and sulcal effacement on CT in which a transient sodium increase masked a clinically relevant hyponatremia thereby delaying diagnosis. This phenomenon is caused by an extracellular water shift and can occur when blood analysis is performed shortly after vigorous exercise or a seizure. This case provides awareness for a less well-known cause of plasma sodium increase and offers recommendations to prevent misinterpretation and help clinicians in decision making.

Prognostic Impact of Hyponatremia and Hypernatremia in COVID-19 Pneumonia. A HOPE-COVID-19 (Health Outcome Predictive Evaluation for COVID-19) Registry Analysis

Dysnatremia is associated with increased mortality in patients with community-acquired pneumonia. SARS-COV2 (Severe-acute-respiratory syndrome caused by Coronavirus-type 2) pneumonia can be fatal. The aim of this study was to ascertain whether admittance dysnatremia is associated with mortality, sepsis, or intensive therapy (IT) in patients hospitalized with SARS-COV2 pneumonia. This is a retrospective study of the HOPE-COVID-19 registry, with data collected from January 1^th through April 31^th, 2020. We selected all hospitalized adult patients with RT-PCR-confirmed SARS-COV2 pneumonia and a registered admission serum sodium level (SNa). Patients were classified as hyponatremic (SNa <135 mmol/L), eunatremic (SNa 135-145 mmol/L), or hypernatremic (SNa >145 mmol/L). Multivariable analyses were performed to elucidate independent relationships of admission hyponatremia and hypernatremia, with mortality, sepsis, or IT during hospitalization. Four thousand six hundred sixty-four patients were analyzed, median age 66 (52-77), 58% males. Death occurred in 988 (21.2%) patients, sepsis was diagnosed in 551 (12%) and IT in 838 (18.4%). Hyponatremia was present in 957/4,664 (20.5%) patients, and hypernatremia in 174/4,664 (3.7%). Both hyponatremia and hypernatremia were associated with mortality and sepsis. Only hyponatremia was associated with IT. In conclusion, hyponatremia and hypernatremia at admission are factors independently associated with mortality and sepsis in patients hospitalized with SARS-COV2 pneumonia.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT04334291, NCT04334291.

Sex-specific risks of death in patients hospitalized for hyponatremia: a population-based study

PURPOSE

Several studies have reported an association between hyponatremia and lethality. However, it remains elusive whether hyponatremia independently contributes to lethality. The aim of the study was to investigate associations between hyponatremia and lethality and differences in lethality between men and women hospitalized due to hyponatremia.

METHODS

Four registries were utilized in this population-based retrospective study: The National Patient Registry, the Cause of Death Register, the Swedish Prescribed Drug Register and the Total Population Register (NPR) from which the controls were sampled. All hospitalized patients with a first-ever principal ICD10 diagnosis of hyponatremia or syndrome of inappropriate ADH secretion in the NPR between 1 October 2005 and 31 December 2014 were defined as cases. Cox regression with adjustment for potential confounders was used.

RESULTS

14,359 individuals with a principal diagnosis of hyponatremia, and 57,382 matched controls were identified. Median age was 76 years and the majority were women (72%). Median age for women and men was 79 and 68 years, respectively. Adjusted hazard ratios (and 95% CI) for lethality in those with hyponatremia compared with controls were for the entire population 5.5 (4.4-7.0) and in the subgroup free from previously known underlying disease 6.7 (3.3-13.3). Lethality in women with hyponatremia was lower compared with men: HR: 0.56 (0.49-0.64). In the healthier group the lethality remained lower for women: HR: 0.49 (0.34-0.71).

CONCLUSIONS

Patients hospitalized due to hyponatremia faced an increased subsequent lethality that was independent of concomitant disease. This increase was nearly twice as large among men compared with women.

A new experimental mouse model of water intoxication with sustained increased intracranial pressure and mild hyponatremia without side effects of antidiuretics

The most used experimental mouse model of hyponatremia and elevated intracranial pressure (ICP) is intraperitoneal injection of water in combination with antidiuretics. This model of water intoxication (WI) results in extreme pathological changes and death within 1 h. To improve preclinical studies of the pathophysiology of elevated ICP, we characterized diuresis, cardiovascular parameters, blood ionogram and effects of antidiuretics in this model. We subsequently developed a new mouse model with mild hyponatremia and sustained increased ICP. To investigate the classical protocol (severe WI), C57BL/6mice were anesthetized and received an intraperitoneal injection of 20% body weight of MilliQ water with or without 0.4 µg·kg^-1 desmopressin acetate (dDAVP). Corresponding Sham groups were also studied. In the new WI protocol (mild WI), 10% body weight of a solution containing 6.5 mM NaHCO₃, 1.125 mM KCl and 29.75 mM NaCl was intraperitoneally injected. By severe WI, ICP and mean arterial pressure increased until brain stem herniation occurred (23 ± 3 min after injection). The cardiovascular effects were accelerated by dDAVP. Severe WI induced a halt to urine production irrespective of the use of dDAVP. Following the new mild WI protocol, ICP also increased but was sustained at a pathologically high level without inducing herniation. Mean arterial pressure and urine production were not affected during mild WI. In conclusion, the new mild WI protocol is a superior experimental model to study the pathophysiological effects of elevated ICP induced by water intoxication.

Intravenous maintenance fluid tonicity and hyponatremia after major surgery- a cohort study

BACKGROUND

Intravenous maintenance fluid (IMF) tonicity and composition influence plasma electrolyte balance.

OBJECTIVE

To determine if hypotonic IMF therapy contributes to post-surgical hyponatremia.

SETTING

Single-center tertiary institution.

PARTICIPANTS

Adults who underwent major surgery and received peri-surgical IMF, with exclusive administration of hypotonic pre-mixed 0.33% saline, 5% dextrose and potassium chloride (DK0.33%S), or isotonic 0.9% saline with or without 5% dextrose (NS/DNS).

OUTCOMES AND MEASURES

We examined post-surgical hyponatremia, hypokalemia and acute kidney injury (AKI), associated with use of either IMF.

RESULTS

We studied 659 patients, of whom 161 patients (24%) developed post-surgical hyponatremia. DK0.33%S (versus NS/DNS) IMF was administered in 52% of patients who developed hyponatremia, compared to 38% of patients with stable natremia (p = 0.001). More patients with hyponatremia underwent gastrointestinal-hepatobiliary or abdominal (GI/HBS/Abd) surgery versus other surgical-sites (p = 0.001). Hypokalemia developed in 1% versus 10% of patients who received DK0.33%S and NS/DNS IMF respectively (p< 0.001), with corresponding AKI rates of 3% versus 7% (p = 0.02). On multivariate analysis, adjusted for timing of biochemistry post-surgery, IMF infusion rate and volume; independent factors associated with post-surgical hyponatremia included DK0.33%S administration, GI/HBS/Abd surgery (versus other sites), and post-surgical AKI (p < 0.05). Subgroup analysis by surgical sites showed that association of DK0.33%S administration with hyponatremia was most evident in GI/HBS/Abd surgery.

CONCLUSIONS

Administration of DK0.33%S IMF, compared with NS/DNS, is associated with post-surgical hyponatremia in adults after major surgery, but with less hypokalemia. The higher rate of AKI observed with NS/DNS IMF requires further evaluation.

Clinico-etiological profile of hyponatremia among elderly age group patients in a tertiary care hospital in Sikkim

Background

Hyponatremia is a common condition observed in hospitalized patients. The incidence is much more in the elderly patients owing to impaired ability to maintain water and electrolyte homeostasis. It is important to evaluate and understand the causes and patient characteristics in order to deliver precise management.

Materials and Methods

Study was conducted at a teaching referral hospital in Sikkim and total of 100 elderly patients, diagnosed with hyponatremia, were enrolled in the study. Detailed medical history, clinical and laboratory examination were performed and data including treatment details were collected. Descriptive analysis was performed and results were correlated with patient characteristics.

Results

Mean age of the patients was 73.87 ± 6.54 years with a male to female ratio of 1:0.96. About 81% of patients were symptomatic among which lethargy (50%), drowsiness (40%), and abnormal behavior (39%) were common symptoms. Most patients (51%) had profound hyponatremia and Syndrome of inappropriate antidiuretic hormone secretion (SIADH) (36%) and drugs (26%) were the most common cause of hyponatremia in this study. The common treatment given in this study was 0.9% NaCl (71%). Mortality of patients in this study was 20%.

Conclusion

Clinicians need to be aware of the common occurrence of hyponatremia in the elderly, especially acutely sick elderly. A systematic approach to its diagnosis with the application of simple standardized diagnostic algorithms can significantly improve the assessment and management of hyponatremia as the outcome in profound hyponatremia is governed by etiology, and not by the serum sodium level.

Misconceptions and Barriers to the Use of Hypertonic Saline to Treat Hyponatremic Encephalopathy

Hyponatremic encephalopathy is a potentially life-threatening condition with a high associated morbidity and mortality. It can be difficult to diagnose as the presenting symptoms can be non-specific and do not always correlate with the degree of hyponatremia. It can rapidly progress leading to death from transtentorial herniation. Hypertonic saline is the recommended treatment for hyponatremic encephalopathy, whether acute or chronic, yet it is infrequently used. We believe that the main barriers to its use is the perception that hypertonic saline is associated with a significant risk for cerebral demyelination, that it can't be administered through a peripheral IV and that it requires monitoring in the ICU. Two illustrative cases are presented followed by a discussion of how intermittent bolus's of 100−150 ml of 3% NaCl in rapid succession to acutely increase the plasma sodium by 4−6 mEq/L is a safe and effective way to treat hyponatremic encephalopathy, that can be administered through a peripheral IV in a non-ICU setting.

Management of hyponatremia: causes, clinical aspects, differential diagnosis and treatment

INTRODUCTION

Hyponatremia is the most frequent electrolyte disorder in hospitalised patients. Acute and severe hyponatremia may be a life-threatening situation. However, also mild and chronic hyponatremia may negatively affect the health status (i.e. gait disturbances, attention deficits, falls and fractures, and bone loss) and may increase the risk of death. Therefore, it is of paramount importance for clinicians to have an in-depth knowledge on this topic, in order to appropriately manage patients affected by hyponatremia.

AREAS COVERED

This review will cover different areas related to this electrolyte disorder. Because many pathologic conditions may be associated with hyponatremia, thorough investigations have to be performed in order to establish the underlying etiology. To establish the cause of hyponatremia is of great importance, because an appropriate therapeutic strategy is strictly dependent on a correct diagnosis. A description of the different available therapeutic approaches for the correction of hyponatremia, including vaptans, will follow.

EXPERT COMMENTARY

Undoubtedly, the studies that have been published in recent years and the introduction of vaptans in clinical practice have contributed to increase the awareness on hyponatremia among clinicians. Nevertheless, additional studies are needed in order to clarify some partially uncovered areas.