Treatment of symptomatic hyponatremia with hypertonic saline: a real-life observational study

Safety of Rapid Intermittent Bolus versus Slow Continuous Infusion of Hypertonic Saline for Managing Symptomatic Severe Hyponatremia: A Systematic Review and Meta-analysis

AIMS

Three percent hypertonic saline (3NS) is an established treatment for severe hyponatremia. The optimal regimen for administering 3NS for severe hyponatremia, with the aim to minimize side effects is not known. This systematic review and meta-analysis aimed to evaluate the safety profile of rapid intermittent bolus (RIB) versus slow continuous infusion (SCI) of 3NS for managing symptomatic severe hyponatremia.

METHODS

Databases were searched for studies evaluating the use of RIB versus SCI/conventional therapy of 3NS for managing symptomatic severe hyponatremia. The primary outcome was to evaluate the occurrence of overcorrection of hyponatremia. Secondary outcomes were to evaluate the need for relowering therapy, duration of hospital stay, changes in sodium levels, osmotic demyelination syndrome (ODS), and mortality.

RESULTS

Data from three studies (290 patients) with severe hyponatremia was analyzed. Patients receiving RIB had a similar occurrence of overcorrection (relative risk [RR]: 1.59 [0.40, 6.35]; I2 = 61%; P = 0.51), need for relowering treatment to bring down serum sodium back to the normal range (RR: 2.53 [0.32, 20.20]; I2 = 81%; P = 0.38), ODS (RR: 2.24 [0.09, 57.18]; P = 0.63) and mortality (RR: 0.51 [0.08, 3.30]; I2 = 31%; P = 0.48), as compared to those receiving SCI. Patients receiving RIB had a marginally higher duration of hospital stay, which approached statistical significance (mean difference: 3.71 days [-0.18, 7.59]; I2 = 0%; P = 0.06).

CONCLUSION

Both RIB and SCI of hypertonic saline were safe and effective for managing severe symptomatic hyponatremia. The reduced duration of hospital stay with SCI of hypertonic saline may suggest this may be the optimal way of administering hypertonic saline.

Clinical factors associated with hyponatremia correction during treatment with oral urea

BACKGROUND

Oral urea is being used more commonly to treat hyponatremia, but factors contributing to the correction rate are unknown. We hypothesized that clinically relevant factors can be identified to help guide hyponatremia correction with oral urea.

METHODS

This was a retrospective study in two university hospitals including hospitalized patients with hyponatremia (plasma sodium <135 mmol/L) treated with oral urea. Linear mixed-effects models were used to identify factors associated with hyponatremia correction. Rates of overcorrection, osmotic demyelination and treatment discontinuation were also assessed.

RESULTS

We included 161 urea treatment episodes in 140 patients (median age 69 years, 46% females, 93% syndrome of inappropriate antidiuresis). Oral urea succeeded fluid restriction in 117 treatment episodes (73%), was combined with fluid restriction in 104 treatment episodes (65%) and was given as the only treatment in 27 treatment episodes (17%). A median dose of 30 g/day of urea for 4 days (interquartile range 2-7 days) increased plasma sodium from 127 to 134 mmol/L and normalized hyponatremia in 47% of treatment episodes. Older age (β 0.09, 95% CI 0.02-0.16), lower baseline plasma sodium (β -0.65, 95% CI -0.78 to -0.62) and higher cumulative urea dose (β 0.03, 95% CI -0.02 to -0.03) were independently associated with a greater rise in plasma sodium. Concurrent fluid restriction was associated with a greater rise in plasma sodium only during the first 48 h of treatment (β 1.81, 95% CI 0.40-3.08). Overcorrection occurred in 5 cases (3%), no cases of osmotic demyelination were identified and oral urea was discontinued in 11 cases (11%) due to side effects.

CONCLUSION

During treatment with oral urea, older age, higher cumulative dose, lower baseline plasma sodium and initial fluid restriction are associated with a greater correction rate of hyponatremia. These factors may guide clinicians to achieve a gradual correction of hyponatremia with oral urea.

Correction of profound hyponatraemia following rapid bolus therapy: effectiveness of the Barsoum-Levine formula based on the Edelman equation

Background

The optimal treatment for profound hyponatraemia remains uncertain. Recent clinical studies have demonstrated that a standardized bolus of hypertonic saline is effective, but relying solely on this approach may not fully address the individual variability of hyponatraemia among patients. We evaluated the effectiveness of rapid bolus (RB) administration of hypertonic saline followed by predictive correction (PC) using an infusate and fluid loss formula identical to the Barsoum-Levine formula based on the Edelman equation (RB-PC) for managing profound hyponatraemia.

Methods

In this retrospective observational cohort study, we evaluated 276 patients aged >18 years with s[Na] levels ≤120 mEq/L (January 2014-December 2023). Using propensity score matching (PSM), we assessed s[Na] elevations at 6 h post-treatment initiation and the rate of appropriate hyponatraemia correction between the RB-PC and PC groups. We defined the appropriate correction as a change in s[Na] in the range of 4-10 mEq/L within the first 24 h and ≤18 mEq/L within the first 48 h following corrective treatment initiation.

Results

Among 276 patients with profound hyponatraemia (s[Na] ≤120 mEq/L), 49 and 108 underwent treatment with RB-PC therapy and with PC therapy without RB, respectively. Post-PSM, 84 patients were selected and allocated to the RB-PC (n = 42) or PC group (n = 42). In PSM analysis, patients with RB-PC experienced a higher elevation in s[Na] at 6 h after treatment initiation than PC (4.0 vs 2.4 mEq/L, P < 0.001). The rate of appropriate correction was similar between the RB-PC and PC groups (90.5% vs 90.5%, P = 1).

Conclusions

RB-PC can quickly elevate s[Na] levels and achieve appropriate correction of s[Na] in patients with profound hyponatraemia.

Supplementation with ions enhances the efficiency of nucleic acid delivery with cell-penetrating peptides

The successful delivery of therapeutic nucleic acids (NAs) into eukaryotic cells is essential for numerous biomedical applications, including gene therapy, gene silencing, and genome editing. Cell-penetrating peptides (CPPs) have claimed significant attention as delivery vehicles due to their inherent ability to penetrate cellular membranes and efficiently transport cargo, including NAs, into the cells. However, further optimization and a deeper understanding of underlying mechanisms are necessary for such transfection methods. Previous studies have demonstrated that Ca2+ ions can significantly enhance NA delivery efficiency when included in transfection media or CPP/NA nanoparticles during preparation. Similar effects have been observed for Mg2+, but the impact of other ions in this context has not been thoroughly investigated. In this study, we supplemented the CPP/NA formulations with various inorganic biocompatible ions by introducing solutions of the respective salts to colloidal nanoparticles at the preparation stage. Our results indicated that supplementing the CPP/NA formulations with certain salt solutions enhanced the biological effect achieved with NAs while also influencing nanoparticle size, surface charge, complexation stability, and, to some extent, the internalization route. Our findings offer valuable insights for optimizing the formation of CPP nanoparticles to improve NA delivery efficiency.

Hyponatraemia-treatment standard 2024

Hyponatraemia is the most common electrolyte disorder in hospital patients associated with increased morbidity, mortality, hospital stay and financial burden. The speed of a correction with 3% sodium chloride as a 100- to 150-ml intravenous bolus or continuous infusion depends on the severity and persistence of the symptoms and needs frequent biochemical monitoring. The rapid intermittent administration of hypertonic saline is preferred for treatment of symptomatic hyponatraemia. In asymptomatic mild hyponatraemia, an adequate solute intake with an initial fluid restriction (FR) of 500 ml/day adjusted according to the serum sodium (sNa) levels is preferred. Almost half of the syndrome of inappropriate antidiuretic hormone (SIADH) patients do not respond to FR as first-line therapy. At present, urea and tolvaptan are considered the most effective second-line therapies in SIADH. However, the evidence for guidance on the choice of second-line therapy of hypotonic hyponatraemia is lacking. Oral urea is considered to be a very effective and safe treatment. Mild and asymptomatic hyponatraemia is treated with adequate solute intake (salt and protein) and initial FR with adjustments based on sNa levels. Specific treatment with vaptans may be considered in either euvolaemic or hypervolaemic patients with high ADH activity. In order to ensure optimal patient outcome, close monitoring and readiness for administration of either hypotonic fluids or desmopressin may be crucial in the decision-making process for specific treatment and eventual overcorrection consequences. According to the guidelines, gradual correction and clinical evaluation is preferable over rapid normalization of sNa towards the laboratory reference ranges.

Point-of-care ultrasound is a useful adjunct tool to a clinician's assessment in the evaluation of severe hyponatraemia

INTRODUCTION

Hyponatraemia is the most common electrolyte disorder in inpatients resulting mainly from an imbalance in water homeostasis. Intravascular fluid status assessment is pivotal but is often challenging given multimorbidity, polypharmacy and diuretics use. We evaluated the utility of point-of-care ultrasound (POCUS) as an adjunct tool to standard practice for fluid assessment in severe hyponatraemia patients.

METHODS

Patients presenting with severe hyponatremia (Serum Sodium [Na] < 120 mmol/L; Normal range: 135-145 mol/L), managed by standard care were included. Hyponatraemia biochemistry work-up and POCUS examination were undertaken. Both clinician and POCUS independently assigned one of the three fluid status groups of hypovolaemia, hypervolaemia or euvolaemia. The final diagnosis of three fluid status groups at admission was made at the time of discharge by retrospective case review. Clinician's (standard of care) and POCUS fluid assessments were compared to that of the final diagnosis at the time of discharge.

RESULTS

n = 19 patients were included. Median Na on admission was 113 mmol/L (109-116), improved to 129 ± 3 mmol/L on discharge. POCUS showed the higher degree of agreement with the final diagnosis (84%; n = 16/19), followed by the clinician (63%; n = 12/19). A trend towards higher accuracy of POCUS compared to clinician assessment of fluid status was noted (84% vs. 63%, p = 0.1611). Biochemistry was unreliable in 58% (n = 11/19) likely due to renal failure, polypharmacy or diuretic use. Inappropriate emergency fluid management was undertaken in 37% (n = 7/19) of cases based on initial clinician assessment. Thirst symptom correlated to hypovolaemia in 80% (4/5) cases.

CONCLUSION

As subjective clinical and biochemistry assessments of fluid status are often unreliable due to co-morbidities and concurrent use of medications, POCUS can be a rapid objective diagnostic tool to assess fluid status in patients with severe hyponatraemia, to guide accurate emergency fluid management.

[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.

Overcorrection and undercorrection with fixed dosing of bolus hypertonic saline for symptomatic hyponatremia

OBJECTIVE

Current guidelines recommend treating symptomatic hyponatremia with rapid bolus-wise infusion of fixed volumes of hypertonic saline regardless of body weight. We hypothesize that this approach is associated with overcorrection and undercorrection in patients with low and high body weight.

DESIGN

Single-center, retrospective cohort study.

METHODS

Data were collected on patients treated with ≥1 bolus 100 or 150 mL 3% NaCl for symptomatic hyponatremia between 2017 and 2021. Outcomes were overcorrection (plasma sodium rise > 10 mmol/L/24 h, > 18 mmol/L/48 h, or relowering therapy) and undercorrection (plasma sodium rise < 5 mmol/L/24 h). Low body weight and high body weight were defined according to the lowest (≤60 kg) and highest (≥80 kg) quartiles.

RESULTS

Hypertonic saline was administered to 180 patients and caused plasma sodium to rise from 120 mmol/L to 126.4 mmol/L (24 h) and 130.4 mmol/L (48 h). Overcorrection occurred in 32 patients (18%) and was independently associated with lower body weight, weight ≤ 60 kg, lower baseline plasma sodium, volume depletion, hypokalemia, and less boluses. In patients without rapidly reversible causes of hyponatremia, overcorrection still occurred more often in patients ≤ 60 kg. Undercorrection occurred in 52 patients (29%) and was not associated with body weight or weight ≥ 80 kg but was associated with weight ≥ 100 kg and lean body weight in patients with obesity.

CONCLUSION

Our real-world data suggest that fixed dosing of bolus hypertonic saline may expose patients with low and high body weight to more overcorrection and undercorrection, respectively. Prospective studies are needed to develop and validate individualized dosing models.

NaCl 3% bolus therapy as emergency treatment for severe hyponatremia: Comparison of 100 ml versus 250 ml

CONTEXT

The aim of initial treatment of severe hyponatremia is to rapidly increase serum sodium to reduce the complications of cerebral edema. The optimal strategy to achieve this goal safely is still under debate.

OBJECTIVE

To compare the efficacy and safety of 100 and 250 ml NaCl 3% rapid bolus therapy as initial treatment of severe hypotonic hyponatremia.

DESIGN

Retrospective analysis of patients admitted between 2017 and 2019.

SETTING

Teaching hospital in the Netherlands.

PATIENTS

130 adults with severe hypotonic hyponatremia, defined as serum sodium ≤ 120 mmol/L.

INTERVENTION

A bolus of either 100 ml (N = 63) or 250 ml (N = 67) NaCl 3% as initial treatment.

MAIN OUTCOME MEASURES

Successful treatment was defined as a rise in serum sodium ≥ 5 mmol/L within the first 4 hours after bolus therapy. Overcorrection of serum sodium was defined as an increase of more than 10 mmol/L in the first 24 hours.

RESULTS

The percentage of patients with a rise in serum sodium ≥ 5 mmol/L within 4 hours was 32% and 52% after a bolus of 100 and 250 ml, respectively (P=0.018). Overcorrection of serum sodium was observed after a median of 13 hours (range 9 - 17 hours) in 21% of patients in both treatment groups (P=0.971). Osmotic demyelination syndrome did not occur.

CONCLUSION

Initial treatment of severe hypotonic hyponatremia is more effective with a NaCl 3% bolus of 250 ml than of 100 ml and does not increase the risk of overcorrection.

Disorders of Salt and Water Balance After Pituitary Surgery

Transsphenoidal surgery is the first-line treatment for many clinically significant pituitary tumors and sellar lesions. Although complication rates are low when performed at high-volume centers, disorders of salt and water balance are relatively common postoperatively. Both, or either, central diabetes insipidus (recently renamed arginine vasopressin deficiency - AVP-D), caused by a deficiency in production and/or secretion of arginine vasopressin, and hyponatremia, most commonly secondary to the syndrome of inappropriate antidiuresis, may occur. These conditions can extend hospital stay and increase the risk of readmission. This article discusses common presentations of salt and water balance disorders following pituitary surgery, the pathophysiology of these conditions, and their diagnosis and management.

Administration of 3% Sodium Chloride and Local Infusion Reactions

Three-percent sodium chloride (3% NaCl) is a hyperosmolar agent used to treat hyponatremic encephalopathy or other cases of increased intracranial pressure. A barrier to the use of 3% NaCl is the perceived risk of local infusion reactions when administered through a peripheral vein. We sought to evaluate reports of local infusion reactions associated with 3% NaCl over a 10-year period throughout a large healthcare system. A query was conducted through the Risk Master database to determine if there were any local infusion reactions associated with peripheral 3% NaCl administration throughout the entire UPMC health system, which consists of 40 hospitals with 8400 licensed beds, over a 10-year time period from 14 May 2010 to 14 May 2020. Search terms included infiltrations, extravasations, phlebitis, IV site issues, and IV solutions. There were 23,714 non-chemotherapeutic and non-contrast-associated intravenous events, of which 4678 (19.7%) were at UPMC Children’s Hospital. A total of 2306 patients received 3% NaCl, of whom 836 (35.8%) were at UPMC Children’s Hospital. There were no reported local infusion reactions with 3% NaCl. There were no reported local infusion reaction events associated with 3% NaCl in a large healthcare system over a 10-year period. This suggests that 3% NaCl can be safely administered through a peripheral IV or central venous catheter.

Treatment of hyponatremia in children with acute bacterial meningitis

Purpose

Few studies have evaluated hyponatremia management in children with bacterial meningitis (BM). Thus, we aimed to describe variations in clinical practice, the effectiveness of sodium management, and adverse outcomes in children with BM and hyponatremia.

Methods

This retrospective cross-sectional study conducted at a tertiary institution analyzed participants' demographic, clinical, and sodium-altering treatment data. The sodium trigger for treatment was defined as pretreatment sodium level, with response and overcorrection defined as increments of ≥5 and &gt;10 mmol/L after 24 h, respectively.

Results

This study enrolled 364 children with BM (age: &lt;16 years; 215 boys). Hyponatremia occurred in 62.1% of patients, among whom 25.7% received sodium-altering therapies; 91.4% of those individuals had moderate/severe hyponatremia. Monotherapy was the most common initial hyponatremia treatment. After 24 h of treatment initiation, 82.4% of the patients responded. Logistic regression analyses revealed that ΔNa24 &lt;5 mmol/L [odds ratio (OR) 15.52, 95% CI 1.71–141.06, p = 0.015] and minimum Glasgow Coma Scale (GCS) score ≤ 8 (OR 11.09, 95% CI 1.16–105.73, p = 0.036) predicted dysnatremia at 48 h after treatment initiation. Although rare, persistent moderate/severe hyponatremia or hypernatremia at 48 h after treatment initiation was associated with a high mortality rate (57.1%).

Conclusion

This study found that most cases of hyponatremia responded well to various treatments. It is important to identify and institute appropriate treatment early for moderate or severe hyponatremia or hypernatremia in children with BM. This study was limited by its non-randomized nature.

Hyponatremia in the emergency department

Hyponatremia, defined as a serum sodium <135 mmol/L, is frequently encountered in patients presenting to the emergency department. Symptoms are often unspecific and include a recent history of falls, weakness and vertigo. Common causes of hyponatremia include diuretics, heart failure as well as Syndrome of Inappropriate Antidiuresis (SIAD) and correct diagnosis can be challenging. Emergency treatment of hyponatremia should be guided by presence of symptoms and focus on distinguishing between acute and chronic hyponatremia.

Diagnosis and Management of Hyponatremia: A Review

IMPORTANCE

Hyponatremia is the most common electrolyte disorder and it affects approximately 5% of adults and 35% of hospitalized patients. Hyponatremia is defined by a serum sodium level of less than 135 mEq/L and most commonly results from water retention. Even mild hyponatremia is associated with increased hospital stay and mortality.

OBSERVATIONS

Symptoms and signs of hyponatremia range from mild and nonspecific (such as weakness or nausea) to severe and life-threatening (such as seizures or coma). Symptom severity depends on the rapidity of development, duration, and severity of hyponatremia. Mild chronic hyponatremia is associated with cognitive impairment, gait disturbances, and increased rates of falls and fractures. In a prospective study, patients with hyponatremia more frequently reported a history of falling compared with people with normal serum sodium levels (23.8% vs 16.4%, respectively; P < .01) and had a higher rate of new fractures over a mean follow-up of 7.4 years (23.3% vs 17.3%; P < .004). Hyponatremia is a secondary cause of osteoporosis. When evaluating patients, clinicians should categorize them according to their fluid volume status (hypovolemic hyponatremia, euvolemic hyponatremia, or hypervolemic hyponatremia). For most patients, the approach to managing hyponatremia should consist of treating the underlying cause. Urea and vaptans can be effective treatments for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but have adverse effects (eg, poor palatability and gastric intolerance with urea; and overly rapid correction of hyponatremia and increased thirst with vaptans). Severely symptomatic hyponatremia (with signs of somnolence, obtundation, coma, seizures, or cardiorespiratory distress) is a medical emergency. US and European guidelines recommend treating severely symptomatic hyponatremia with bolus hypertonic saline to reverse hyponatremic encephalopathy by increasing the serum sodium level by 4 mEq/L to 6 mEq/L within 1 to 2 hours but by no more than 10 mEq/L (correction limit) within the first 24 hours. This treatment approach exceeds the correction limit in about 4.5% to 28% of people. Overly rapid correction of chronic hyponatremia may cause osmotic demyelination, a rare but severe neurological condition, which can result in parkinsonism, quadriparesis, or even death.

CONCLUSIONS AND RELEVANCE

Hyponatremia affects approximately 5% of adults and 35% of patients who are hospitalized. Most patients should be managed by treating their underlying disease and according to whether they have hypovolemic, euvolemic, or hypervolemic hyponatremia. Urea and vaptans can be effective in managing the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure; hypertonic saline is reserved for patients with severely symptomatic hyponatremia.

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.

Hypertonic saline for severe symptomatic hyponatraemia: real-world findings from the UK

Objective

To evaluate 'real-world' safety and efficacy of the European Society of Endocrinology guidelines for the treatment of severe symptomatic hyponatraemia using hypertonic saline (HTS).

Design

Retrospective, observational, cohort study, examining the use of HTS for severe symptomatic hyponatraemia at Sheffield Teaching Hospitals between 2017 and 2020.

Methods

Patients were identified from pharmacy records and demographic, clinical, and treatment data extracted.

Results

Out of 112 patients (females:males = 61:51), the mean age ± s.d. was 66.3± 16.0 years and mean pre-treatment serum sodium ± s.d. was 113.8 ± 6.4 mmol/L. Overall, overcorrection rates at 24 and 48 h (>10 and >18 mmol/L) were 44.9 and 19.6%, respectively, while 19.6% of patients were treated for overcorrection. Above-target rise in sodium (>5 mmol/L) after first and second boluses was noted in 22.6 and 34.6% of patients, respectively. In-hospital and 12-month mortality was 7.1 and 18.7%, respectively, with no cases of osmotic demyelination. The mean venous blood gas (VBG) sodium was 1.9 mmol/L lower than paired serum sodium (n = 36) (113.6 ± 6.6 vs 115.7 ± 7.8 mmol/L).

Conclusion

We report real-world data demonstrating that a significant number of patients overcorrected using current guidelines. Also, several patients had above-target rise in sodium after one bolus of HTS, and sodium measurement should be considered before the second bolus unless ongoing severe symptoms persist. A point of care VBG sodium concentration was useful for this purpose. In addition to careful monitoring, a cautious but anticipatory overcorrection prevention strategy should be considered in the first 24 h.

Edelman Revisited: Concepts, Achievements, and Challenges

The key message from the 1958 Edelman study states that combinations of external gains or losses of sodium, potassium and water leading to an increase of the fraction (total body sodium plus total body potassium) over total body water will raise the serum sodium concentration ([Na]_S), while external gains or losses leading to a decrease in this fraction will lower [Na]_S. A variety of studies have supported this concept and current quantitative methods for correcting dysnatremias, including formulas calculating the volume of saline needed for a change in [Na]_S are based on it. Not accounting for external losses of sodium, potassium and water during treatment and faulty values for body water inserted in the formulas predicting the change in [Na]_S affect the accuracy of these formulas. Newly described factors potentially affecting the change in [Na]_S during treatment of dysnatremias include the following: (a) exchanges during development or correction of dysnatremias between osmotically inactive sodium stored in tissues and osmotically active sodium in solution in body fluids; (b) chemical binding of part of body water to macromolecules which would decrease the amount of body water available for osmotic exchanges; and (c) genetic influences on the determination of sodium concentration in body fluids. The effects of these newer developments on the methods of treatment of dysnatremias are not well-established and will need extensive studying. Currently, monitoring of serum sodium concentration remains a critical step during treatment of dysnatremias.

The management of acute and chronic hyponatraemia

Hyponatraemia is the most common electrolyte abnormality encountered in clinical practice; despite this, the work-up and management of hyponatraemia remain suboptimal and varies among different specialist groups. The majority of data comparing hyponatraemia treatments have been observational, up until recently. The past two years have seen the publication of several randomised control trials investigating hyponatraemia treatments, both for chronic and acute hyponatraemia. In this article, we aim to provide a background to the physiology, cause and impact of hyponatraemia and summarise the most recent data on treatments for acute and chronic hyponatraemia, highlighting their efficacy, tolerability and adverse effects.

Management of SIADH-related hyponatremia due to psychotropic medications - An expert consensus from the Association of Medicine and Psychiatry

OBJECTIVE

Hyponatremia is the most common electrolyte imbalance encountered in clinical practice and is associated with negative healthcare outcomes and cost. SIADH is thought to account for one third of all hyponatremia cases and is typically an insidious process. Psychotropic medications are commonly implicated in the etiology of drug induced SIADH. There is limited guidance for clinicians on management of psychotropic-induced SIADH.

METHODS

After an extensive review of the existing literature, clinical-educators from the Association of Medicine and Psychiatry developed expert consensus recommendations for management of psychotropic-induced SIADH. A risk score was proposed based on risk factors for SIADH to guide clinical decision-making.

RESULTS

SSRIs, SNRIs, antipsychotics, carbamazepine, and oxcarbazepine have moderate to high level of evidence demonstrating their association with SIADH. Evaluation for an avoidance of medications that cause hyponatremia is particularly important. Substitution with medication that is less likely to cause SIADH should be considered when appropriate. We propose an algorithmic approach to monitoring hyponatremia with SIADH and corresponding treatment depending on symptom severity.

CONCLUSIONS

The proposed algorithm can help clinicians in determining whether psychotropic medication should be stopped, reduced or substituted where SIADH is suspected with recommendations for sodium (Na+) monitoring. These recommendations preserve a role for clinical judgment in the management of hyponatremia with consideration of the risks and benefits, which may be particularly relevant for complex patients that present with medical and psychiatric comorbidities. Further studies are needed to determine whether baseline and serial Na+ monitoring reduces morbidity and mortality.

[Hypo- and hypernatremia in the intensive care unit : Pitfalls in volume management]

Hypo- and hypernatremias are very frequent in intensive care unit (ICU) patients and are closely related to volume disturbances and volume management in the ICU. They are associated with longer ICU stays and significant increases in mortality. Treating them is more complex than it may initially appear. Hyponatremias are differentiated based on tonicity and volume status. With hypertonic and isotonic hyponatremias, the primary focus of treatment is the underlying hyperglycemia. In case of hypotonic hypovolemic hyponatremia, the condition is treated with balanced crystalloid solutions. In eu-/hypervolemic hypotonic hyponatremias acute treatment with hypertonic saline is necessary. Hypervolemic hypernatremia occurs almost exclusively in ICU patients, often due to infusion of hypertonic solutions. There is little evidence to guide treatment, although hypotonic infusions in conjunction with diuretics may represent a legitimate approach. Great emphasis should be placed on prevention and the infusion of hypertonic solutions should be avoided. Disturbances in plasma sodium concentrations are common, requiring close attention. Exact diagnostic classification needs to be made and volume managed accordingly.

Hypertonic Saline for Hyponatremia: Meeting Goals and Avoiding Harm

Hypertonic saline has been used for the treatment of hyponatremia for nearly a century. There is now general consensus that hypertonic saline should be used in patients with hyponatremia associated with moderate or severe symptoms to prevent neurological complications. However, much less agreement exists among experts regarding other aspects of its use. Should hypertonic saline be administered as a bolus injection or continuous infusion? What is the appropriate dose? Is a central venous line necessary? Should desmopressin be used concomitantly and for how long? This article considers these important questions, briefly explores the historical origins of hypertonic saline use for hyponatremia, and reviews recent evidence behind its indications, dosing, administration modality and route, combined use with desmopressin to prevent rapid correction of serum sodium, and other considerations such as the need and degree for fluid restriction. The authors conclude by offering some practical recommendations for the use of hypertonic saline.