Complications and management of hyponatremia:

Efficacy of oral sodium chloride in reducing the incidence of hyponatremia in children with epilepsy receiving oxcarbazepine monotherapy: A randomized controlled trial (SCHO Trial)

INTRODUCTION

Hyponatremia is a well-documented adverse effect of oxcarbazepine treatment, but no clinical trial has yet been conducted to explore any intervention for reducing the incidence of hyponatremia.

MATERIALS AND METHODS

This open-label trial evaluated the efficacy of add-on daily oral sodium chloride supplementation of 1-2 g/day for 12 weeks in reducing the incidence of hyponatremia in children receiving oxcarbazepine monotherapy aged 1-18 years. Apart from comparing the incidence of symptomatic and severe hyponatremia, serum and urine sodium levels, serum and urine osmolality, changes in behavior and cognition, and the number of participants with recurrence of seizures and requiring additional antiseizure medication (ASM) were also compared.

RESULTS

A total of 120 children (60 in each group) were enrolled. The serum sodium level at 12 weeks in the intervention group was higher than that of the control group (136.5 ± 2.6 vs 135.4 ± 2.5 mEq/L, p = 0.01). The number of patients with hyponatremia was significantly lower in the intervention group (4/60vs14/60, p = 0.01). However, the incidence of symptomatic and severe hyponatremia (0/60vs1/60, p = 0.67 for both), changes in social quotient and child behavior checklist total score (0.6 ± 0.8 vs 0.7 ± 0.5, p = 0.41 and 0.9 ± 1.2 vs 1.1 ± 0.9, p = 0.30 respectively), the number of patients with breakthrough seizures (9/60vs10/60, p = 0.89), and the number of patients requiring additional ASMs (8/60vs10/60, p = 0.79) were comparable in both groups.

CONCLUSIONS

Daily oral sodium chloride supplementation is safe and efficacious in reducing the incidence of hyponatremia in children with epilepsy receiving oxcarbazepine monotherapy. However, sodium chloride supplementation does not significantly reduce more clinically meaningful outcome measures like symptomatic and severe hyponatremia. Trial registry No. CTRI/2021/12/038388.

Association between hyponatremia and adverse clinical outcomes of heart failure: current evidence based on a systematic review and meta-analysis

Background

Heart failure (HF) is a global health challenge. The perturbations in fluid and electrolyte equilibrium, particularly the compromised sodium balance associated with HF lead to high mortality rates. Hence, elucidating the correlation between serum sodium levels and the prognosis of HF is of paramount importance. This study aimed to conduct a comprehensive meta-analysis to thoroughly investigate the interplay between hyponatremia and the prognostic outlook of individuals with HF.

Methods

A comprehensive search of bibliographic databases including PubMed, Embase, and the Cochrane Central Register of Controlled Trials was conducted to identify relevant observational studies examining the association between hyponatremia and prognosis of HF. Data extraction, synthesis, and assessment of risk of bias were conducted. Meta-analytic methods, sensitivity analyses, and heterogeneity test were employed as appropriate to synthesize the data.

Results

A total of 43,316 patients with HF were included spanning 25 selected studies. The pooled data revealed a notable association between hyponatremia and elevated risks across short and long-term mortality of HF. Specifically, hyponatremia was found to significantly increase the likelihood of all-cause mortality (Hazard ratio [HR] = 1.94, 95% confidence interval [CI]: 1.78-2.12); 1-year mortality (HR = 1.67, 95%CI: 1.46-1.90); 30-day mortality (HR = 2.03, 95%CI: 1.73-2.25); cardiac mortality (HR = 2.11, 95%CI: 1.81-2.46); and in-hospital mortality (HR = 1.64, 95%CI: 1.15-2.34).

Conclusion

Our meta-analysis emphasizes the significant impact of hyponatremia on mortality in the HF patient population, highlighting the critical importance of maintaining stable serum sodium levels in HF management.

Probing antibacterial drugs for Fusobacterium nucleatum subsp. nucleatum ATCC 25586 targeting UDP-N-acetylglucosamine 1-carboxyltransferase

Fusobacterium nucleatum is a Gram-negative anaerobic bacteria that is commonly found in oral cavities and is associated with connective tissue destruction in periodontitis. UDP-N-acetylglucosamine 1-carboxyltransferase with enzyme commission number 2.5.1.7 is a transferases enzyme that plays a role in bacterial pathogenesis. Inhibiting binding sites of UDP-N-acetylglucosamine 1-carboxyltransferase is needed to find potential antibiotic candidates for periodontitis treatment. Hence, the research aimed to present potential UDP-N-acetylglucosamine 1-carboxyltransferase inhibiting compounds through molecular docking simulation by in silico analysis. DrugBank database was used to obtain the antibacterial candidates, which were further screened computationally using the AutoDock Vina program on Google Colab Pro. The top nine compounds yielded binding affinity ranging from -12.1 to -12.8 kcal/mol, with conivaptan as one of the three compounds having the highest binding affinity. Molecular dynamic study revealed that the ligand-protein complex for conivaptan had root-mean-square deviation values of 0.05-1.1 nm, indicating likeliness for stable interaction. Our findings suggest that conivaptan is the potent UDP-N-acetylglucosamine 1-carboxyltransferase inhibitor, hence its efficacy against periodontitis-causing bacteria.

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.

Trauma-related electrolyte disturbances: From resuscitation to rhabdomyolysis

Traumatic injury results in drastic changes to a patient's normal physiology. The hormonal stress response, as well as some treatment strategies, lead to significant disruptions in electrolyte homeostasis that are important for clinicians to understand. In addition, advances in fluid resuscitation and modern transfusion practices have led to their own unique set of consequences, which we are just beginning to appreciate. Special attention is placed on rhabdomyolysis, as this distinct entity represents an extreme example of injury induced electrolyte derangements. This review describes the physiologic response to trauma and highlights some of the important electrolyte abnormalities that can be encountered while caring for the injured patient.

Hyponatraemia and the syndrome of inappropriate antidiuresis (SIAD) in cancer

Hyponatraemia is a common electrolyte abnormality seen in a wide range of oncological and haematological malignancies and confers poor performance status, prolonged hospital admission and reduced overall survival, in patients with cancer. Syndrome of inappropriate antidiuresis (SIAD) is the commonest cause of hyponatraemia in malignancy and is characterised by clinical euvolaemia, low plasma osmolality and concentrated urine, with normal renal, adrenal and thyroid function. Causes of SIAD include ectopic production of vasopressin (AVP) from an underlying tumour, cancer treatments, nausea and pain. Cortisol deficiency is an important differential in the assessment of hyponatraemia, as it has an identical biochemical pattern to SIAD and is easily treatable. This is particularly relevant with the increasing use of immune checkpoint inhibitors, which can cause hypophysitis and adrenalitis, leading to cortisol deficiency. Guidelines on the management of acute, symptomatic hyponatraemia recommend 100 mL bolus of 3% saline with careful monitoring of the serum sodium to prevent overcorrection. In cases of chronic hyponatraemia, fluid restriction is recommended as first-line treatment; however, this is frequently not feasible in patients with cancer and has been shown to have limited efficacy. Vasopressin-2 receptor antagonists (vaptans) may be preferable, as they effectively increase sodium levels in SIAD and do not require fluid restriction. Active management of hyponatraemia is increasingly recognised as an important component of oncological management; correction of hyponatraemia is associated with shorter hospital stay and prolonged survival. The awareness of the impact of hyponatraemia and the positive benefits of active restoration of normonatraemia remain challenging in oncology.

Prevalence and Prognostic Significance of Hyponatremia in Patients With Lung Cancer: Systematic Review and Meta-Analysis

Background: The prevalence of hyponatremia is highly variable among patients with lung cancer. However, its prevalence and prognostic significance in subgroups of patients with lung cancer have not yet been evaluated in a meta-analysis. Methods: We have registered our meta-analysis and review protocol to the PROSPERO International Prospective Register of Systematic Reviews, with the following registration number: CRD42020167013. A systematic search was done in the following sources: MEDLINE, Embase, CENTRAL, Web of Science, ClinicalTrials.gov, a WHO Global Health Library. Results: We identified a total of 8,962 potentially eligible studies, and we included 31 articles in our evaluation. The prevalence of hyponatremia in patients with lung cancer varied between 3 and 94.8% with an average of 25% without any significant differences between the following subgroups: histotype, gender, age, Eastern Cooperative Oncology Group (ECOG) state, and the extent of disease. The overall survival (OS) was significantly lower in hyponatremic compared to normonatremic patients at 10 months [RR.59 (95% CI.47-0.74), p < 0.001] and at 20 months [RR.44 (95% CI.33-0.59), p < 0.001], with worse survival rates in non-small cell lung cancer (NSCLC) [RR.27 (95% CI.12-0.44), p < 0.001] than in small cell lung cancer (SCLC) [RR.42 (95% CI.27-0.57), p < 0.001]. If hyponatremia was corrected, OS at 10 months was significantly higher than in the uncorrected hyponatremia group [RR 1.83 (95% CI 1.37-2.44), p < 0.001], but, at 20 months, no statistically significant difference could be found between these subgroups [RR 2.65 (95% CI.94-7.50), p = 0.067]. Conclusions: Patients with lung cancer diagnosed with hyponatremia, especially patients with NSCLC, seem to have significantly lower survival rates than normonatremic patients. If hyponatremia remains uncorrected, the mortality rates might be even higher.

Potential Use of Pharmacogenetics to Reduce Drug-Induced Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

Syndrome of inappropriate antidiuretic hormone (SIADH) is a common cause of hyponatremia, and many cases represent adverse reactions to drugs that alter ion channel conductance within the peptidergic nerve terminals of the posterior pituitary. The frequency of drug-induced SIADH increases with age; as many as 20% of patients residing in nursing homes have serum sodium levels below 135 mEq/L. Mild hyponatremia is associated with cognitive changes, gait instability, and falls. Severe hyponatremia is associated with cerebral edema, seizures, permanent disability, and/or death. Although pharmacogenetic tests are now being deployed for some drugs capable of causing SIADH (e.g., antidepressants, antipsychotics, and opioid analgesics), the implementation of these tests has been based upon the prior known association of these drugs with other serious adverse drug reactions (e.g., electrocardiographic abnormalities). Work is needed in large observational cohorts to quantify the strength of association between pharmacogene variants and drug-induced SIADH so that decision support can be developed to identify patients at high risk.

Subarachnoid Hemorrhage Early Brain Edema Score (SEBES) as a radiographic marker of clinically relevant intracranial hypertension and unfavorable outcome after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The severity of early brain edema (EBE) after aneurysm rupture was reported to be strongly associated with the risk of poor outcome after aneurysmal subarachnoid hemorrhage (SAH). Using the recently developed Subarachnoid Hemorrhage Early Brain Edema Score (SEBES), we analyzed the predictors of EBE and its impact on complications related to intracranial pressure (ICP) increase after SAH and on poor outcome.

METHODS

All consecutive SAH cases treated between January 2003 and June 2016 with assessable SEBES were included (n = 745). Data on demographic characteristics, medical history, initial severity of SAH, need for conservative ICP treatment and decompressive craniectomy, occurrence of cerebral infarctions and unfavorable outcome at 6 months (modified Rankin scale score > 2) were collected. Univariable and multivariable analyses were performed.

RESULTS

Younger age (<55 years; adjusted odds ratio [aOR] 3.16, 95% confidence interval [CI] 2.28-4.38), female sex (aOR 1.64, 95% CI 1.16-2.31), poor initial clinical condition (World Federation of Neurosurgical Societies score 4-5; aOR 1.74, 95% CI 1.23-2.46), presence of intracerebral hemorrhage (aOR 1.63, 95% CI 1.12-2.36), hypothyroidism (aOR 0.60, 95% CI 0.37-0.98) and renal comorbidity (aOR 0.29, 95% CI 0.11-0.78) were independently associated with SEBES (scores 3-4). There was an independent association between SEBES 3-4 and the need for conservative ICP treatment (aOR 2.43, 95% CI 1.73-3.42), decompressive craniectomy (aOR 2.68, 95% CI 1.84-3.89), development of cerebral infarcts (aOR 2.24, 95% CI 1.53-3.29) and unfavorable outcome (aOR 1.48, 95% CI 1.0-2.17).

CONCLUSIONS

SEBES is a reliable predictor of ICP-related complications and poor outcome of SAH. Our findings highlight the need for further research of the impact of patients' demographic characteristics and comorbidities on the severity of EBE after SAH.

Association Between an Increase in Serum Sodium and In-Hospital Mortality in Critically Ill Patients

Supplemental Digital Content is available in the text.

OBJECTIVES:

In critically ill patients, dysnatremia is common, and in these patients, in-hospital mortality is higher. It remains unknown whether changes of serum sodium after ICU admission affect mortality, especially whether normalization of mild hyponatremia improves survival.

DESIGN:

Retrospective cohort study.

SETTING:

Ten Dutch ICUs between January 2011 and April 2017.

Patients:

Adult patients were included if at least one serum sodium measurement within 24 hours of ICU admission and at least one serum sodium measurement 24–48 hours after ICU admission were available.

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

A logistic regression model adjusted for age, sex, and Acute Physiology and Chronic Health Evaluation-IV–predicted mortality was used to assess the difference between mean of sodium measurements 24–48 hours after ICU admission and first serum sodium measurement at ICU admission (Δ48 hr-[Na]) and in-hospital mortality. In total, 36,660 patients were included for analysis. An increase in serum sodium was independently associated with a higher risk of in-hospital mortality in patients admitted with normonatremia (Δ48 hr-[Na] 5–10 mmol/L odds ratio: 1.61 [1.44–1.79], Δ48 hr-[Na] > 10 mmol/L odds ratio: 4.10 [3.20–5.24]) and hypernatremia (Δ48 hr-[Na] 5–10 mmol/L odds ratio: 1.47 [1.02–2.14], Δ48 hr-[Na] > 10 mmol/L odds ratio: 8.46 [3.31–21.64]). In patients admitted with mild hyponatremia and Δ48 hr-[Na] greater than 5 mmol/L, no significant difference in hospital mortality was found (odds ratio, 1.11 [0.99–1.25]).

CONCLUSIONS:

An increase in serum sodium in the first 48 hours of ICU admission was associated with higher in-hospital mortality in patients admitted with normonatremia and in patients admitted with hypernatremia.

Severe Hyponatremia and Seizure From Peripheral Infusion of Norepinephrine Diluted in Dextrose 5% in Water: A Case Report

Recent studies have demonstrated that vasopressors can be delivered safely through peripheral intravenous lines. While norepinephrine is usually delivered at a concentration of 16 to 32 μg/mL, out of concern for extravasation and interstitial necrosis, some patients receive more dilute norepinephrine solutions through peripheral intravenous catheters. We describe a case of severe hyponatremia and seizure resulting from administration of norepinephrine concentrated at 4 μg/mL in dextrose 5% in water. After the incident, the institutional policy changed to recommend normal saline as the default diluent for peripheral norepinephrine, with a more concentrated option available. The incident also informed similar guidelines at other hospitals.

Evaluation of Desmopressin in Critically Ill Patients with Hyponatremia Requiring 3% Hypertonic Saline

BACKGROUND

Desmopressin (DDAVP) is often used for hyponatremia management but has been associated with increases in hospital length of stay and duration of hypertonic saline use. The purpose of this study was to evaluate hyponatremia management strategies and their effect on sodium correction in critically ill patients requiring 3% hypertonic saline (3HS).

METHODS

This retrospective, single-center study included critically ill patients with hyponatremia (serum sodium ≤ 125 mEq/L) receiving 3HS from May 31 2015, to May 31 2019. Patients were divided into those who received 3HS for hyponatremia management (HTS) and those who received proactive or reactive DDAVP in addition to 3HS (D-HTS). Patients in either group could receive rescue DDAVP. The primary outcome was the percentage of patients achieving goal sodium correction of 5-10 mEq/L 24 h after 3HS initiation.

RESULTS

Goal sodium correction was achieved in 52.5% of patients in HTS compared to 65.6% of patients in D-HTS (p = 0.21). Patients in HTS had a shorter duration of 3HS infusion (p = 0.0022) with no difference in ICU length of stay, free water intake, urine output, or serum sodium increases 12 and 24 h after receiving 3HS. Overcorrection during any 24- or 48 h period was not statistically different between groups.

CONCLUSION

Patients in HTS and D-HTS had similar rates of achieving goal sodium correction at 24 h. A proactive or reactive DDAVP strategy led to an increase in 3HS duration and total amount with no significant difference in rates of overcorrection. Prospective, randomized studies assessing standardized strategies for hyponatremia management and DDAVP administration are warranted.

Preeclampsia and low sodium: A retrospective cohort analysis and literature review

BACKGROUND

The aim of this study was to retrospectively analyze the prevalence of severe preeclampsia and low sodium (PALS) among the pregnant population admitted at the University Hospital of Udine in the past 4 years and to compare these data with the current literature.

METHODS

Only women with a diagnosis of preeclampsia were included. According to the lowest sodium level measured either 5 days before or 5 days after delivery, patients were divided in two groups: women with hyponatremia (<135 mmol/L; severe <120 mmol/L) and women with normonatremia (>135 mmol/L). Moreover, a search literature was performed.

RESULTS

Of 59 patients with preeclampsia, 20 (34%) had hyponatremia. Only one case (1.6%) of severe maternal hyponatremia (sodium level 117 mmol/L) in the setting of preeclampsia was identified. After literature search, a total of 22 manuscripts including 60 case reports of PALS were identified. The lowest sodium level was 113 mmol/L, at 25 weeks of gestation. In most cases hyponatremia was treated with fluid restriction. In only 5 cases hyponatremia was treated with a saline hypertonic solution. Hyponatremia resolution, when reported, occurred in about 48 h. Sodium level in neonates ranged from 118 and 128 mmol/L.

CONCLUSIONS

PALS may occur in about a third of women with severe preeclampsia. Severe maternal hyponatremia should be treated with fluid restriction and with hypertonic saline solution. Moreover neonatologists should be alerted in order to treat the neonate for the best outcome.

Amelioration of risk factors associated with diabetic nephropathy in diet-induced pre-diabetic rats by an uracil-derived diimine ruthenium(II) compound

Diabetic renal injury advances through different stages of structural and functional changes in the glomerulus, therefore treatment during the pre-diabetic state could be used as therapeutic target in the management and prevention of diabetic nephropathy (DN). Once diagnosed, dietary interventions and pharmacological therapy have been recommended to manage DN and pre-diabetic related complications. However, poor patient compliance still results, therefore newer alternative drugs are required. High fat high carbohydrates (HFHC) diet was used to induce pre-diabetes for 20 weeks. After the induction, pre-diabetic rats were randomly allocated to respective treatment groups. Subcutaneous ruthenium(II) Schiff base complex injection (15 mg/kg) was administered to pre-diabetic rats in both the presence and absence of dietary intervention once a day every third day for 12 weeks. The administration of ruthenium(II) complex resulted in reduced blood glucose, aldosterone, fluid intake and urinary output which correlated with a restoration in plasma and urinary electrolytes along with plasma antioxidants concentration. Furthermore, there was a decrease in kidney injury molecule-1 (KIM-1) concentration, albumin excretion rate (AER) albumin creatinine ratio (ACR) and mRNA expression of podocin in urine in ruthenium-treated pre-diabetic rats. Ruthenium(II) Schiff base complex ameliorated renal function while preventing the progression of DN in prediabetic-treated rats.

Omeprazole-induced and pantoprazole-induced asymptomatic hyponatremia: a case report

BACKGROUND

Hyponatremia is the most common electrolyte disorder. Thiazides, antidepressants, antipsychotic drugs, and antiepileptic drugs are well-known causes of hyponatremia. Proton pump inhibitor use is a rare cause of hyponatremia and, when reported, it is due to one specific proton pump inhibitor, mostly omeprazole.

CASE PRESENTATION

A 67-year-old Caucasian male was referred to our out-patient clinic because of hyponatremia (127 mmol/L) found at routine laboratory examination. He had consulted his general practitioner because of abdominal pains. No other symptoms were present. At physical examination, he appeared euvolemic and had no abdominal tenderness. Besides omeprazole for reflux esophagitis he used no medication. Additional laboratory results included: serum osmolarity 274 mOsmol/kg, urinary osmolarity 570 mOsmol/kg, and urinary sodium 35 mmol/L. Other causes of hyponatremia were excluded and we diagnosed hyponatremia due to the syndrome of inappropriate antidiuretic hormone secretion secondary to use of omeprazole. Omeprazole was replaced by ranitidine after which his serum sodium levels normalized to 135 mmol/L. During follow-up, because of persistent reflux complaints despite ranitidine use, ranitidine was switched to another proton pump inhibitor: pantoprazole. After this intervention, his serum sodium level declined again to 133 mmol/L. We concluded that both omeprazole and pantoprazole induced syndrome of inappropriate antidiuretic hormone secretion in this patient.

CONCLUSION

Hyponatremia is worrisome and awareness of medication-induced hyponatremia, especially due to proton pump inhibitors, is needed. In our case, sequential hyponatremia occurred with two different proton pump inhibitors, suggesting a class effect. Therefore, when syndrome of inappropriate antidiuretic hormone secretion due to a proton pump inhibitor is diagnosed, preferably no other medication from the same class is prescribed. When after consideration another proton pump inhibitor is prescribed, serum sodium concentrations should be monitored.

Sodium and health-concordance and controversy

Nancy Cook and colleagues describe the sources of agreement and disagreement about the health effects of sodium and how they might be resolved

Magnesium, Calcium, Potassium, Sodium, Phosphorus, Selenium, Zinc, and Chromium Levels in Alcohol Use Disorder: A Review

Macronutrients and trace elements are important components of living tissues that have different metabolic properties and functions. Trace elements participate in the regulation of immunity through humoral and cellular mechanisms, nerve conduction, muscle spasms, membrane potential regulation as well as mitochondrial activity and enzymatic reactions. Excessive alcohol consumption disrupts the concentrations of crucial trace elements, also increasing the risk of enhanced oxidative stress and alcohol-related liver diseases. In this review, we present the status of selected macroelements and trace elements in the serum and plasma of people chronically consuming alcohol. Such knowledge helps to understand the mechanisms of chronic alcohol-use disorder and to progress and prevent withdrawal effects, also improving treatment strategies.

Risk factors for sodium overcorrection in non-hypovolemic hyponatremia patients treated with tolvaptan

PURPOSE

In this study, the risk factors associated with sodium overcorrection were investigated with an optimal cutoff for baseline serum sodium for use in daily clinical practice.

METHODS

Electronic medical records of patients who received tolvaptan for non-hypovolemic hyponatremia were reviewed. Demographic and clinical data including age, sex, weight, height, comorbidity, cause of hyponatremia, hypertonic saline use, and comedication were collected. Baseline laboratory parameters measured included serum sodium, serum potassium, serum creatinine, blood urea nitrogen, serum tonicity, ALT, AST, and urine osmolality. The primary outcome was the overcorrection of serum sodium, which was defined as an increase in serum sodium by more than 10 mmol/L in 24 h.

RESULTS

From a total of 77 patients included in the analysis, 24 (31.2%) showed sodium overcorrection (> 10 mmol/L/24 h); 2 (2.6%) in heart failure cohort, 17 (22.1%) in SIADH cohort, and 5 (6.5%) in unknown cause cohort. More than half of patients (51.9%) were administered hypertonic saline prior to tolvaptan. Hypertension, cancer, diuretics, baseline serum sodium, and SIADH were associated with the risk of overcorrection in the univariable analysis. Significant factors for the overcorrection from multivariable analysis were lower body mass index, presence of cancer (adjusted odds ratio, 10.87; 95% CI, 1.23-96.44), and lower serum sodium at baseline (adjusted odds ratio, 0.76 for every 1 mEq/L increase; 95% CI, 0.61-0.94).

CONCLUSION

The overcorrection of hyponatremia in non-hypovolemic patients treated with tolvaptan was significantly associated with lower body mass index, presence of cancer, and lower serum sodium at baseline. In subgroup analysis using SIADH patients, baseline sodium and cancer were found to be significant factors of overcorrection.

"Pleurex Desalination" in Malignancy-related Ascites: A Novel Mechanism of Hyponatremia

OBJECTIVE

Pleurex catheters are a form of palliative therapy for patients, offering relief from symptomatic ascites while also affording greater independence and flexibility; however, aggressive drainage can lead to significant total body sodium losses. We describe the course of patients with "Pleurex desalination," an under-appreciated cause of hypovolemic hyponatremia, highlighting its unique pathophysiology and providing recommendations on how to manage these complex patients.

PATIENTS AND METHODS

We included representative patients with "Pleurex desalination" who were evaluated and treated by the renal consult service at Brigham and Women's between 2017 and 2019.

RESULTS

We identified 3 patients who were hospitalized with "Pleurex desalination" and had complete data on serum and urine studies, as well as treatment course. We demonstrate that patients with "Pleurex desalination" were removing up to 1 to 2 L of ascitic fluid a day and were admitted with signs and symptoms of profound hypovolemia and hyponatremia. Patients worsened with administration of diuretics and salt restriction and improved with aggressive fluid resuscitation in the form of hypertonic saline, normal saline, and/or intravenous albumin.

CONCLUSION

"Pleurex desalination" is an under-recognized cause of hyponatremia; at-risk patients require close observation and periodic resuscitation with intravenous, volume-expanding fluids.

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.

Acute Hyponatremia Resulting from Duloxetine-induced Syndrome of Inappropriate Antidiuretic Hormone Secretion

A 77-year-old woman who had taken a single oral dose of duloxetine subsequently developed a headache and nausea. On the first day, her serum sodium level was 135 mEq/L. She became confused on the third day. Her serum sodium level was 119 mEq/L and her antidiuretic hormone level was 1.9 IU. We diagnosed her with acute hyponatremia from duloxetine-induced syndrome of inappropriate antidiuretic hormone secretion (SIADH). This case suggests that we must not rule out SIADH on the basis of normal serum sodium levels when a patient who has started serotonin-norepinephrine reuptake inhibitor (SNRI) treatment presents with symptoms similar to hyponatremia.

Allostasis and the Clinical Manifestations of Mild to Moderate Chronic Hyponatremia: No Good Adaptation Goes Unpunished

When homeostatic regulatory systems are unable to maintain a normal serum sodium concentration, the organism must adapt to demands of a disordered internal environment, a process known as "allostasis." Human cells respond to osmotic stress created by an abnormal serum sodium level with the same adaptations used by invertebrate organisms that do not regulate body fluid osmolality. To avoid intolerable changes in their volume, cells export organic osmolytes when exposed to a low serum sodium concentration and accumulate these intracellular solutes when serum sodium concentration increases. The brain's adaptation to severe hyponatremia (serum sodium < 120 mEq/L) has been studied extensively. However, adaptive responses occur with less severe hyponatremia and other tissues are affected; the consequences of these adaptations are incompletely understood. Recent epidemiologic studies have shown that mild (sodium, 130-135 mEq/L) and moderate (sodium, 121-129 mEq/L) chronic hyponatremia, long thought to be inconsequential, is associated with adverse outcomes. Adaptations of the heart, bone, brain, and (possibly) immune system to sustained mild to moderate hyponatremia may adversely affect their function and potentially the organism's survival. This review explores what is known about the consequences of mild to moderate chronic hyponatremia and the potential benefits of treating this condition.

Desmopressin-Induced Severe Hyponatremia with Central Pontine Myelinolysis: A Case Report

Desmopressin, a synthetic vasopressin analog, is used to treat central diabetes insipidus, hemostatic disorders such as von Willebrand’s disease, and nocturnal enuresis. We present the case of a 69-year-old man who developed severe hyponatremia during treatment with intranasal desmopressin at 10 µg twice daily for chronic polyuria and nocturia thought to be due to central diabetes insipidus. After 5 months of therapy, the patient noticed progressive fatigue, anorexia, dizziness, weakness, light-headedness, decreased concentration, and new-onset falls. At 6 months of therapy, the patient was brought to the emergency department for altered mental status and was found to be severely hyponatremic with a serum sodium level of 96 mmol/L, down from a value of 134 mmol/L at the initiation of therapy. The intranasal desmopressin was discontinued and the patient was admitted to the intensive care unit where the hyponatremia was slowly corrected over the next week to 132 mmol/L, never increasing by more than 8 mmol/L a day, with careful fluid management. This included infusion of over 11 L of 5% dextrose to account for a high urine output, which peaked at 7.4 L in 1 day. However, while the recommended rate for sodium correction was followed, the patient’s magnetic resonance imaging of the brain obtained after discharge displayed evidence of central pontine myelinolysis. Despite this finding, the patient eventually returned to his baseline mental status with no permanent neurologic deficits.

Outcomes in Severe Hyponatremia Treated With and Without Desmopressin

BACKGROUND

Overcorrection of plasma sodium in severe hyponatremia is associated with osmotic demyelination syndrome. Desmopressin (DDAVP) can prevent overcorrection of plasma sodium in hyponatremia. The objective of this study was to compare outcomes in hyponatremia according to DDAVP usage.

METHODS

This was a retrospective observational study including all admissions to internal medicine with hyponatremia (plasma sodium concentration <123 mEq/L) from 2004 to 2014 at 2 academic hospitals in Toronto, Canada. The primary outcome was safe sodium correction (≤12 mEq/L in any 24-hour and ≤18 mEq/L in any 48-hour period).

RESULTS

We identified 1450 admissions with severe hyponatremia; DDAVP was administered in 254 (17.5%). Although DDAVP reduced the rate of change of plasma sodium, fewer patients in the DDAVP group achieved safe correction (174 of 251 [69.3%] vs 970 of 1164 [83.3%]); this result was driven largely by overcorrection occurring before DDAVP administration in the rescue group. Among patients receiving DDAVP, most received it according to a reactive strategy, whereby DDAVP was given after a change in plasma sodium within correction limits (174 of 254 [68.5%]). Suspected osmotic demyelination syndrome was identified in 4 of 1450 admissions (0.28%). There was lower mortality in the DDAVP group (3.9% vs 9.4%), although this is likely affected by confounding. Length of stay in hospital was longer in those who received DDAVP according to a proactive strategy.

CONCLUSIONS

Although observational, these data support a reactive strategy for using DDAVP in patients at average risk of osmotic demyelination syndrome, as well as a more stringent plasma sodium correction limit of 8 mEq/L in any 24-hour period for high-risk patients. Further studies are urgently needed on DDAVP use in treating hyponatremia.

Emergencies in Hematology and Oncology

The development of medical emergencies related to the underlying disease or as a result of complications of therapy are common in patients with hematologic or solid tumors. These oncological emergencies can occur as an initial presentation or in a patient with an established diagnosis and are encountered in all medical care settings, ranging from primary care to the emergency department and various subspecialty environments. Therefore, it is critically important that all physicians have a working knowledge of the potential oncological emergencies that may present in their practice and how to provide the most effective care without delay. This article reviews the most common oncological emergencies and provides practical guidance for initial management of these patients.

Formulas for fixing serum sodium: curb your enthusiasm

A variety of formulas have been proposed to predict changes in serum sodium concentration. All are based on an experiment done over 50 years ago by Edelman, who derived a formula relating the plasma sodium concentration to isotopically measured body sodium, potassium, and water. Some of these formulas fail because they do not include urinary losses of electrolytes and water. Even those that include these essential variables are not accurate enough for clinical use because it is impractical to adjust calculations to rapid changes in urinary composition, and because the formulas do not account for changes in serum sodium caused by internal exchanges between soluble and bound sodium stores or shifts of water into or out of cells resulting from changes in intracellular organic osmolytes. Nephrologists should curb their enthusiasm for predictive formulas and rely instead on frequent measurements of the serum sodium when correcting hyponatremia and hypernatremia.