Incidence of osmotic demyelination syndrome in Sweden: A nationwide study

Mortality and causes of death in patients hospitalized with hyponatremia - a propensity matched cohort study

BACKGROUND

Chronic hyponatremia is common in hospitalized patients and associated with high mortality. To what extent this reflects a causal effect remains uncertain.

METHODS

This study was based on the Stockholm Sodium Cohort, a longitudinal laboratory data repository covering 1.6 million individuals from 2005 to 2018. Using 1:1 propensity score matching, we explored mortality rates and causes of death in patients with mild (130-134 mmol/L), moderate (125-129 mmol/L), profound (120-124 mmol/L) or very profound (<120 mmol/L) hyponatremia compared to patients with normal (135-145 mmol/L) sodium concentrations on admittance to medical wards.

RESULTS

In total, 283 837 individuals fulfilled inclusion criteria, 79 407 of which had hyponatremia. Of these, 66 941 (52.7 % women) were successfully matched to counterparts with normal sodium concentrations. Thirty-day mortality rates were higher in patients with hyponatremia (HRs from 1.35 [95 % CI 1.28-1.42] in mild to 3.38 [95 % CI 2.16-5.28] in very profound hyponatremia). One-year mortality rates were marginally elevated in patients with mild hyponatremia (HR 1.04 [95 %CI 1.01-1.07]), but higher with more pronounced hyponatremia (HRs 1.18 [95 %CI 1.09-1.27] to 1.38 [95 %CI 1.11-1.69]). Excess 30-day mortality in mild, moderate, and profound hyponatremia was largely driven by malignant and gastrointestinal diseases.

CONCLUSIONS

Excess mortality with hyponatremia is proportional to the sodium disturbance but attenuates over time. However, causes of death suggest that residual confounding from imbalanced severity of underlying diseases is the main cause of increased mortality.

Syndrome of Inappropriate Antidiuresis

Syndrome of inappropriate antidiuresis (SIAD)-the most frequent cause of hypotonic hyponatremia-is mediated by nonosmotic release of arginine vasopressin, which promotes water retention by activating renal vasopressin type 2 (V2) receptors. There are numerous causes of SIAD, including malignancy, pulmonary and central nervous system diseases, and medications. Rare activating mutations of the V2 receptor can also cause SIAD. Determination of the etiology of SIAD is important because removal of the stimulus for inappropriate arginine vasopressin secretion offers the most effective therapy. Treatment of SIAD is guided by symptoms and their severity, as well as the level of plasma sodium. In the absence of severe symptoms, which require urgent intervention, many clinicians focus on fluid restriction as a first-line treatment. Second-line therapeutic options include loop diuretics and salt tablets, urea, and V2 receptor antagonists.

Hyponatremia Correction and Osmotic Demyelination Syndrome Risk: A Systematic Review and Meta-Analysis

Rationale & Objective

Osmotic demyelination syndrome (ODS) is a rare but severe condition often attributed to the rate of sodium collection. We evaluated the association between the overly rapid sodium correction in adult hospitalized patients with ODS.

Study Design

Systematic review and meta-analysis.

Setting & Study Populations

Adults hospitalized hyponatremia patients.

Selection Criteria for Studies

The studies comparing the incidence of ODS with and without rapid sodium correction inception to January 2024.

Data Extraction

Two reviewers independently extracted data and assessed the risk of bias and the certainty of evidence.

Analytic Approach

The incidence of ODS following a rapid and nonrapid sodium correction was pooled using the random effects model. Subgroup and meta-regression analyses were performed for the robustness and the source of heterogeneity.

Results

Eleven cohort studies were included with 26,710 hospitalized hyponatremia patients. The definition of hyponatremia varied from <116 to <130 mmol/L, and overly rapid sodium correction was defined as >8 to 12 mmol/L within 24 hours. The overall incidence of ODS was 0.23%. The incidence of ODS in rapid and nonrapid sodium correction was 0.73% and 0.10%, respectively. Meta-analysis demonstrated that a rapid rate of sodium correction was associated with a higher incidence of ODS (odds ratio 3.16, 95% CI, 1.54-6.49, I2 = 27%), whereas some patients with hyponatremia developed ODS without rapid sodium level correction. The sensitivity analysis based on the quality of the studies was consistent with the main result.

Limitation

Various definition criteria for ODS diagnosis across studies, lack of potential electrolyte and treatment data that may affect the incidence of ODS.

Conclusions

The rapid rate of sodium correction had a statistical correlation with a higher incidence of ODS. Among ODS without rapid correction, further studies are recommended to evaluate and comprehend the relationship for better and proper management of hospitalized patients with hyponatremia.

Correction Rates and Clinical Outcomes in Hospitalized Adults With Severe Hyponatremia: A Systematic Review and Meta-Analysis

Importance

Hyponatremia treatment guidelines recommend limiting the correction of severe hyponatremia during the first 24 hours to prevent osmotic demyelination syndrome (ODS). Recent evidence suggests that slower rates of correction are associated with increased mortality.

Objective

To evaluate the association of sodium correction rates with mortality among hospitalized adults with severe hyponatremia.

Data Sources

We searched MEDLINE, Embase, the Cochrane Library, LILACS, Web of Science, CINAHL, and international congress proceedings for studies published between January 2013 and October 2023.

Study Selection

Comparative studies assessing rapid (≥8-10 mEq/L per 24 hours) vs slow (<8 or 6-10 mEq/L per 24 hours) and very slow (<4-6 mEq/L per 24 hours) correction of severe hyponatremia (serum sodium <120 mEq/L or <125 mEq/L plus severe symptoms) in hospitalized patients.

Data Extraction and Synthesis

Pairs of reviewers (N.A.F., J.R.M., J.M.A., A.C.) independently reviewed studies, extracted data, and assessed each included study's risk of bias using ROBINS-I. Cochrane methods, PRISMA reporting guidelines, and the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach to rate the certainty of evidence were followed. Data were pooled using a random-effects model.

Main Outcomes and Measures

Primary outcomes were in-hospital and 30-day mortality, and secondary outcomes were hospital length of stay (LOS) and ODS.

Results

Sixteen cohort studies involving a total of 11 811 patients with severe hyponatremia were included (mean [SD] age, 68.22 [6.88] years; 56.7% female across 15 studies reporting sex). Moderate-certainty evidence showed that rapid correction was associated with 32 (odds ratio, 0.67; 95% CI, 0.55-0.82) and 221 (odds ratio, 0.29; 95% CI, 0.11-0.79) fewer in-hospital deaths per 1000 treated patients compared with slow and very slow correction, respectively. Low-certainty evidence suggested that rapid correction was associated with 61 (risk ratio, 0.55; 95% CI, 0.45-0.67) and 134 (risk ratio, 0.35; 95% CI, 0.28-0.44) fewer deaths per 1000 treated patients at 30 days and with a reduction in LOS of 1.20 (95% CI, 0.51-1.89) and 3.09 (95% CI, 1.21-4.94) days, compared with slow and very slow correction, respectively. Rapid correction was not associated with a statistically significant increased risk of ODS.

Conclusions and Relevance

In this systematic review and meta-analysis, slow correction and very slow correction of severe hyponatremia were associated with an increased risk of mortality and hospital LOS compared to rapid correction.

Unveiling the Patterns of Water Diuresis in Profound Hyponatremia Management in Intensive Care Unit Settings

Key Points

Water diuresis presents a conundrum during the treatment of profound hyponatremia, but its clinical characteristics remain unclear. This study revealed that water diuresis mostly manifests within 24 hours of treatment, preceded by changes in urinary characteristics. Careful urine monitoring in the early stages of hyponatremia treatment could facilitate the early detection of water diuresis.

Background

Hyponatremia treatment guidelines recommend avoiding excessive increases in serum sodium concentration (s[Na]) to prevent osmotic demyelination syndrome. Although an unexpected rise in s[Na] has been attributed to water diuresis during the treatment of hyponatremia, clinical courses of water diuresis are unclear. We conducted this study to investigate the clinical characteristics of water diuresis during profound hyponatremia management.

Methods

In this retrospective observational study, we examined patients with profound hyponatremia (s[Na] ≤120 mEq/L) admitted to the intensive care unit of a Japanese hospital. The manifestation of water diuresis was defined as a urine volume (UV) ≥2 ml/kg per hour and a urinary sodium plus potassium concentration (u[Na+K]) ≤50 mEq/L. We analyzed changes in UV and u[Na+K] over time for patients experiencing water diuresis. This analysis employed a mixed-effects model with spline terms for time, and the results are graphically presented.

Results

Among 47 eligible patients, 30 (64%) met the criteria for water diuresis. The etiologies of hyponatremia were drug-related hyponatremia (n =10; 33%), primary polydipsia (n =8; 27%), hypovolemic hyponatremia (n =7; 23%), syndrome of inappropriate antidiuresis (n =7; 23%), and acute heart failure (n =1; 3%). Among patients with water diuresis, 27 (90%) experienced the manifestation of water diuresis within 24 hours after the start of correction. The increased UV and decreased u[Na+K] levels began several hours before the peak manifestation of water diuresis. Within 6 hours after the manifestation of water diuresis, 29 patients (97%) received electrolyte-free infusions and 14 (47%) received desmopressin. One patient (3%) with water diuresis experienced overcorrection.

Conclusions

Water diuresis is common during the treatment for profound hyponatremia and typically occurs within the first 24 hours, preceded by changes in urinary characteristics. Early detection and prompt response to water diuresis through urine monitoring during the early periods of hyponatremia treatment may be effective for managing water diuresis.

Prolonged extracellular low sodium concentrations and subsequent their rapid correction modulate nitric oxide production dependent on NFAT5 in microglia

Hyponatremia is the most common clinical electrolyte disorder. Chronic hyponatremia has been recently reported to be associated with falls, fracture, osteoporosis, neurocognitive impairment, and mental manifestations. In the treatment of chronic hyponatremia, overly rapid correction of hyponatremia can cause osmotic demyelination syndrome (ODS), a central demyelinating disease that is also associated with neurological morbidity and mortality. Using a rat model, we have previously shown that microglia play a critical role in the pathogenesis of ODS. However, the direct effect of rapid correction of hyponatremia on microglia is unknown. Furthermore, the effect of chronic hyponatremia on microglia remains elusive. Using microglial cell lines BV-2 and 6-3, we show here that low extracellular sodium concentrations (36 mmol/L decrease; LS) suppress Nos2 mRNA expression and nitric oxide (NO) production of microglia. On rapid correction of low sodium concentrations, NO production was significantly increased in both cells, suggesting that acute correction of hyponatremia partly directly contributes to increased Nos2 mRNA expression and NO release in ODS pathophysiology. LS also suppressed expression and nuclear translocation of nuclear factor of activated T cells-5 (NFAT5), a transcription factor that regulates the expression of genes involved in osmotic stress. Furthermore, overexpression of NFAT5 significantly increased Nos2 mRNA expression and NO production in BV-2 cells. Expressions of Nos2 and Nfat5 mRNA were also modulated in microglia isolated from cerebral cortex in chronic hyponatremia model mice. These data indicate that LS modulates microglial NO production dependent on NFAT5 and suggest that microglia contribute to hyponatremia-induced neuronal dysfunctions.

Severe osmotic demyelination syndrome with cortical involvement in the context of severe hyponatremia and central diabetes insipidus: an uncommon presentation of an unusual combination

BACKGROUND

Osmotic demyelination syndrome (ODS) with cerebral cortical involvement is a rare complication of severe hyponatremia correction. Careful management of hyponatremia is crucial, particularly in patients with risk factors, such as alcohol use disorder and diabetes insipidus.

CASE

A patient in his 40s with a history of alcohol use disorder and central diabetes insipidus developed ODS after a 24 mEq/L osmolar increase during the treatment of hyponatremia. The patient's condition progressed into locked-in syndrome and then improved to spastic tetraparesis after cortical basal ganglia ODS improved.

DISCUSSION

The differential diagnosis of cortical demyelination includes laminar cortical necrosis, being the interpretation of Apparent Diffusion Coefficient (ADC) MRI sequence is a useful tool.This case underscores the need to investigate and improve diagnosis and treatment strategies in patients with ODS. It also emphasises the significance of careful hyponatremia correction and frequent monitoring, particularly in patients with known risk factors for ODS.

Treatment Guidelines for Hyponatremia: Stay the Course

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

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.

Risk factors for mortality in brain injury patients who have severe hypernatremia and received continuous venovenous hemofiltration

Background and objectives

The mortality rate for people with brain injuries is increased when hypernatremia is present. Patients with severe hypernatremia, who have a significant short-term mortality rate, were shown to benefit from continuous venovenous hemofiltration (CVVH), which has been indicated to be successful. Exploring the risk factors for short-term mortality in brain injury patients who underwent CVVH and had severe hypernatremia was the aim of the current study.

Materials and methods

Retrospective screening was performed on patients with brain injuries who underwent CVVH at Xijing Hospital between 1 December 2010 and 31 December 2021 and who have a diagnosis of severe hypernatremia. The outcomes included 28-day patient mortality and hospital stay duration. The patient survival rate was examined using the Kaplan-Meier survival curve. To determine the risk factors for short-term death for patients, univariate and multivariate Cox regression analysis models were used.

Results

Our current study included a total of 83 individuals. The included patients had a median age of 49 (IQR 35-59) years. Of the included patients, 58 patients (69.9 %) died within 28 days. The median length of hospital stay for the patient was 13 (IQR 7-21) days. The APACHE II score, SOFA score, GCS, PLT count, INR, stroke, mechanical ventilation, and vasopressor reliance were related to 28-day mortality according to the univariate Cox analysis. INR (HR = 1.004, 95 % Cl: 1.001-1.006, P = 0.008), stroke (HR = 1.971, 95 % Cl: 1.031-3.768, P = 0.04), mechanical ventilation (HR = 3.948, 95 % Cl: 1.090-14.294, P = 0.036), and vasopressor dependency (HR = 2.262, 95 % Cl: 1.099-4.655, P = 0.027) were independently associated with the risk of 28-day death rates, according to multivariate Cox regression analysis.

Conclusions

Brain injuries who have severe hypernatremia requires CVVH, which has high short-term patient mortality. Mechanical ventilation, INR increase, stroke, and vasopressor dependence are independently associated with increased patient mortality risk.

Osmotic demyelination syndrome caused by rapid correction of hyperammonemia and continuous hyperbilirubinemia: a case report and review of the literature

Osmotic demyelination syndrome (ODS) is an acute demyelinating disorder characterized by the loss of myelin in the center of the basis pons, defined as central pontine myelinolysis (CPM), and demyelination in locations outside the pons, defined as extrapontine myelinolysis (EPM). ODS including CPM and EPM is mainly caused by rapid correction of hyponatremia. However, there are several reports of ODS in medical conditions such as malnutrition; alcoholism; liver transplantation; malignancy; sepsis; and electrolyte imbalance including hypernatremia, hypokalemia, hypophosphatemia, and chronic illness. ODS caused by rapid correction of hyperammonemia or continuous hyperbilirubinemia without sodium fluctuations has rarely been reported. Because ODS may be irreversible, prevention is crucial. Herein, we report a case of ODS secondary to rapid correction of hyperammonemia and continuous hyperbilirubinemia.

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.

[Hyponatremia : Etiology, diagnosis and acute therapy]

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

Osmotic demyelination syndrome: novel risk factors and proposed pathophysiology

BACKGROUND

Osmotic demyelination syndrome (ODS) is non-inflammatory demyelination in response to an osmotic challenge. It can be pontine or extrapontine in presentation.

AIMS

To retrospectively review cases involving ODS and define the spectrum of causes, risk factors, clinical and radiological presentations, and functional outcomes.

RESULTS

The study utilised data from 15 patients with a mean age of 53.6 years. Malnutrition (9; 60%) and chronic alcoholism (10; 66.7%) were the most common associated disorders. Two (13.3%) patients had severe hyponatraemia (<120 mmol/L). The average highest single-day change was 5.1 mmol/L. Radiologically, 14 (93.3%) had pontine and 6 (40%) had extra-pontine lesions. Hypokalaemia (14; 93.3%) and hypophosphataemia (9; 60%) were commonly associated. Common clinical manifestations include altered consciousness/encephalopathy (9; 60%), dysphagia (4; 26.7%) and limb weakness (4; 26.7%). At 3 months, two (14.3%) had died and six (40%) were functionally independent (modified Rankin scale 0-2).

CONCLUSION

We found that ODS occurred despite appropriate correction rates of hyponatraemia. Factors such as malnutrition, chronic alcoholism, hypokalaemia and hypophosphataemia are thought to play a role in its pathogenesis. Approximately half of the patients survived and became functionally independent.

Osmotic Demyelination Syndrome in Patients Hospitalized with Hyponatremia

BACKGROUND: Osmotic demyelination syndrome (ODS) is a rare but potentially devastating neurologic complication of hyponatremia. The primary objective of this study was to identify the proportion of patients who developed ODS in a large, contemporary, multicenter cohort of patients admitted to the hospital with hyponatremia. METHODS: We conducted a multicenter cohort study of patients admitted with hyponatremia at five academic hospitals in Toronto, Ontario, Canada, between April 1, 2010, and December 31, 2020. All adult patients presenting with hyponatremia (serum sodium level 8 mmol/l in any 24-hour period). RESULTS: Our cohort included 22,858 hospitalizations with hyponatremia. Approximately 50% were women, the average age was 68 years, and mean initial serum sodium was 125 mmol/l (standard deviation, 4.6), including 11.9% with serum sodium from 110 to 119 mmol/l and 1.2% with serum sodium less than 110 mmol/l. Overall, rapid correction of serum sodium occurred in 3632 (17.7%) admissions. Twelve patients developed ODS (0.05%). Seven (58%) patients who developed ODS did not have rapid correction of serum sodium. CONCLUSIONS: In this large multicenter study of patients with hyponatremia, rapid correction of serum sodium was common (n=3632 [17.7%]), but ODS was rare (n=12 [0.05%]). Future studies with a higher number of patients with ODS are needed to better understand potential causal factors for ODS.

Clinical Approach to Euvolemic Hyponatremia

Euvolemic hyponatremia is frequently encountered in hospitalized patients and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common cause in most patients. SIADH diagnosis is confirmed by decreased serum osmolality, inappropriately elevated urine osmolality (>100 mosmol/L), and elevated urine sodium (Na) levels. Patients should be screened for thiazide use and adrenal or thyroid dysfunction should be ruled out before making a diagnosis of SIADH. Clinical mimics of SIADH like cerebral salt wasting and reset osmostat should be considered in some patients. The distinction between acute (<48 hours) versus chronic (>48 hours or without baseline labs) hyponatremia and clinical symptomatology are important to initiate proper therapy. Acute hyponatremia is a medical emergency and osmotic demyelination syndrome (ODS) occurs commonly when rapidly correcting any chronic hyponatremia. Hypertonic (3%) saline should be used in patients with significant neurologic symptoms and maximal correction of serum Na level should be limited to <8 mEq over 24 hours to prevent the ODS. Simultaneous administration of parenteral desmopressin is one of the best ways to prevent overly rapid Na correction in high-risk patients. Free water restriction combined with increased solute intake (e.g., urea) is the most effective therapy to treat patients with SIADH. 0.9% saline acts as a hypertonic solution in patients with hyponatremia and should be avoided in the treatment of SIADH due to rapid fluctuations in serum Na levels. Dual effects of 0.9% saline resulting in rapid correction of serum Na during infusion (inducing ODS) and post-infusion worsening of serum Na levels are described in the article with clinical examples.

Adaptation of the Brain to Hyponatremia and Its Clinical Implications

Hyponatremia is the most common electrolyte disorder, occurring in up to 25% of hospitalized patients. Hypo-osmotic hyponatremia when severe and left untreated invariably results in cell swelling, which can lead to fatal consequences, especially in the central nervous system. The brain is particularly vulnerable to the consequences of decreased extracellular osmolarity; because of being encased in the rigid skull, it cannot withstand persistent swelling. Moreover, serum sodium is the major determinant of extracellular ionic balance, which in turn governs crucial brain functions such as the excitability of neurons. For these reasons, the human brain has developed specific ways to adapt to hyponatremia and prevent brain edema. On the other hand, it is well known that rapid correction of chronic and severe hyponatremia can lead to brain demyelination, a condition known as osmotic demyelination syndrome. In this paper, we will discuss the mechanisms of brain adaptation to acute and chronic hyponatremia and the neurological symptoms of these conditions as well as the pathophysiology and prevention of osmotic demyelination syndrome.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Diagnosis and treatment of brain injury complicated by hypernatremia

Hypernatremia is a common electrolyte disorder in patients with brain injury. The mortality of brain injury patients with severe hypernatremia may be as high as 86.8%. The efficacy of conventional treatment for hypernatremia is limited. Continuous renal replacement therapy (CRRT) can slowly, controllably, and continuously reduce the blood sodium concentration and gradually become an important treatment for severe hypernatremia patients. This review aims to provide important information for clinicians and clinical researchers by describing the etiology, diagnosis, hazards, conventional treatment, and CRRT treatment of hypernatremia in patients with traumatic brain injury.

Neuroleptic malignant syndrome in a case of extra-pontine myelinolysis: On the horns of dilemma

Osmotic demyelination syndrome (ODS) and neuroleptic malignant syndrome (NMS) lead to severe neurological sequalae. Though currently thought to be different syndromes, literature suggests a relation between the two. We present the case of a 45-year-old male who was found to have chronic severe hyponatremia and underwent rapid correction of sodium and developed parkinsonism features. Magnetic resonance imaging (MRI) confirmed extrapontine myelinolysis (a type of ODS). The patient received haloperidol for agitated behavior and developed new features of rigidity, fever, tachycardia and elevated creatine phosphokinase (CPK) levels and thus neuroleptic malignant syndrome was suspected to overlap with ODS. We report this case highlighting the difficulty in differentiating the between ODS and NMS and their relationship.

Case Report: Osmotic Demyelination Syndrome After Transcatheter Aortic Valve Replacement: Case Report and Review of Current Literature

Background

Osmotic demyelination syndrome (ODS) has a low incidence but is a life-threatening neurological disorder whose common cause is rapid overcorrection of chronic hyponatremia. Transcatheter aortic valve replacement (TAVR) is a new and important therapy for patients with aortic valve stenosis. In this article, we discuss the case of a 64-year-old woman who developed ODS after TAVR and provide a literature review.

Case Presentation

A 64-year-old female patient was admitted to the hospital with chest tightness, shortness of breath, and fatigue for 2 months, with worsening of symptoms for 3 days prior to presentation. Auscultation revealed crackles in the lung fields, and systolic murmurs could be easily heard in the aortic area. Echocardiography showed severe aortic stenosis. Chest X-ray showed pulmonary oedema. Laboratory examinations showed that her serum sodium was 135 mmol/L. The patient received a diuretic to relieve her symptoms but showed little benefit. Her symptoms worsened, and her blood pressure dropped. Then, she underwent emergency TAVR under extracorporeal membrane oxygenation (ECMO) support. After the operation, her urine output increased markedly, and serum sodium increased sharply from 140 to 172 mmol/L. An MRI scan showed multiple lesions in the pons suggestive of ODS.

Conclusion

To date, this is the first reported case of a patient who developed ODS after receiving TAVR. In current clinical practice, diuretics are often used in aortic stenosis patients because of pulmonary oedema. After a patient receives TAVR, kidney perfusion pressure quickly returns to normal, and with the residual effect of a high-dose diuretic, balances of fluid volume and electrolyte levels in this phase are quite fragile and must be carefully managed. If a patient has neurological symptoms/signs during this phase, ODS should be considered, and MRI might be necessary.

Osmotic demyelination syndrome despite appropriate gradual correction of moderate hyponatraemia

Osmotic demyelination syndrome characteristically follows rapid correction of hyponatraemia. We present a young woman with a subacute progressive brainstem syndrome and diffuse pontine signal abnormality on MR imaging, diagnosed as osmotic demyelination syndrome. The case posed a diagnostic challenge due to comorbid Behçet's disease and the absence of significant fluctuation in her serum sodium concentration. Osmotic demyelination syndrome is not limited to patients with rapidly corrected hyponatraemia, especially when there are other risk factors. These factors, all present in this patient, include hypokalaemia, hypophosphataemia, malnutrition, harmful alcohol use and liver dysfunction.

Uremic encephalopathy

Uremic encephalopathy encompasses a wide range of central nervous system abnormalities associated with poor kidney function occurring with either progressive chronic kidney disease or acute kidney injury. The syndrome is likely caused by retention of uremic solutes, alterations in hormonal metabolism, changes in electrolyte and acid-base homeostasis, as well as changes in vascular reactivity, blood-brain barrier transport, and inflammation. There are no defining clinical, laboratory, or imaging findings, and the diagnosis is often made retrospectively when symptoms improve after dialysis or transplantation. The diagnosis is also made difficult because of the many confounding and overlapping conditions seen in patients with chronic kidney disease and acute kidney injury. Thus, institution of kidney replacement therapy should be considered as a trial to improve symptoms in the right clinical context. Neurological symptoms that do not improve after improvement in clearance should prompt a search for other explanations. Further knowledge linking possible uremic retention solutes with neurological symptoms is needed to better understand this syndrome as well as to develop more tailored treatments that aim to improve cognitive function.

Rare case of diffuse large B-cell lymphoma presenting with central pontine myelinolysis

Central pontine myelinolysis (CPM) is commonly associated with osmotic stress and rapid correction of hyponatraemia. It has rarely been reported in conjunction with malignancies. We report a case where CPM was not only associated with a new diagnosis of diffuse large B-cell lymphoma but was also a key presenting feature.

The Spectrum of Movement Disorders in Cases with Osmotic Demyelination Syndrome

Background

Osmotic demyelination syndrome (ODS) can be a central pontine myelinolysis (CPM) and extrapontine myelinolysis (EPM) based on the regions involved even though they share the same disease process, aetiopathogenesis and time course.

Objectives

Present study aims to characterize the clinical, radiological features and the outcome of patients with ODS with movement disorders as the forthcoming manifestation.

Methods

Chart review of patients with ODS with movement disorders. Demographic, clinical and radiological details of the patients were reviewed.

Results

Eleven patients (six females; mean age: 48.3 ± 17.6 years) were included in the study. Parkinsonism alone and parkinsonism with dystonia was noted in four patients each (36.4%) while dystonia alone was noted in the other 3 (27.3%). Five patients (45.5%) had postural tremors. While 5 patients had dystonia early in the course of illness (3-7 days), it was delayed (6-9 months) in the other 2. A triphasic course was noted in two patients. The first phase of hyponatremia induced neurological impairment was followed by a second phase of worsening due to the immediate effect of ODS and a third delayed phase of worsening due to delayed effect of ODS. MRI showed both EPM and CPM in eight patients, EPM alone in two patients and CPM alone in 1 patient. Nine patients had a good outcome with mRS < 3.

Conclusion

Parkinsonism and dystonia are important manifestations of ODS. Triphasic course with a delayed phase of worsening of movement disorders is probably due to the maladaptive neuronal repair. The concept of triphasic ODS is first being described in our series.

Osmotic demyelination syndrome following slow correction of hyponatraemia

Hyponatraemia is the most common electrolyte disturbance observed in hospital inpatients. We report a 90-year-old woman admitted generally unwell following a fall with marked confusion. Examination revealed a tender suprapubic region, and investigations observed elevated inflammatory markers and bacteriuria. Admission investigations demonstrated a serum sodium of 110 mmol/L with associated serum osmolality 236 mmol/kg and urine osmolality 346 mmol/kg. She was treated for hyponatraemia secondary to syndrome of inappropriate antidiuretic hormone (SIADH) and urosepsis. However, her serum sodium failed to normalise despite fluid restriction, necessitating treatment with demeclocycline and hypertonic saline. Despite slow reversal of hyponatraemia over 1 month, the patient developed generalised seizures with pontine and thalamic changes on MRI consistent with osmotic demyelination syndrome (ODS). This case highlights the risk of ODS, a rare but devastating consequence of hyponatraemia treatment, despite cautious sodium correction.

Acute Hyponatremia After a Religious Fast

Objective

Our objective is to describe how polydipsia and intake of nonsteroidal anti-inflammatory drugs (NSAIDs) after fasting while breastfeeding may result in acute symptomatic hyponatremia.

Case Report

We present the case of a 24-year-old woman at 4 weeks postpartum who engaged in a 20-hour fast from both eating and drinking, during which she continued to breastfeed her newborn child. After ending her fast, she noted decreased milk supply. Attributing her decreased milk supply to dehydration, she then consumed 4 L of water with little salt and also took NSAIDs for a headache, which continued to worsen. Upon presentation to the emergency department, she was found to have a sodium level of 124 mEq/L (normal, 135-145 mEq/L) and a urine specific gravity of 1.015 (normal, 1.005 – 1.030). Thyroid function and cortisol level test results were normal. She was diagnosed with acute symptomatic hypovolemic hyponatremia. After 1 L of normal saline her sodium rapidly corrected to normal and her symptoms resolved. At 2 months of follow-up she was asymptomatic and had no further episodes of hyponatremia.

Discussion

Due to the patient’s gender and small body size, 4 L of water was sufficient to lower her serum sodium rapidly from normal to 124 mEq/L. She was unable to excrete this water due to a combination of hypovolemia-mediated arginine vasopressin and NSAID use.

Conclusion

Clinicians should be cognizant that reproductive-age women are uniquely susceptible to hyponatremia and dangerous sequelae therein. They should counsel fasting individuals, particularly lactating women, to consume solute as well as fluid after fasting.

Osmotic Demyelination Syndrome following Correction of Hyponatremia by ≤10 mEq/L per Day

Background

Overly rapid correction of chronic hyponatremia may lead to osmotic demyelination syndrome. European guidelines recommend a correction to ≤10 mEq/L in 24 hours to prevent this complication. However, osmotic demyelination syndrome may occur despite adherence to these guidelines.

Methods

We searched the literature for reports of osmotic demyelination syndrome with rates of correction of hyponatremia ≤10 mEq/L in 24 hours. The reports were reviewed to identify specific risk factors for this complication.

Results

We identified 19 publications with a total of 21 patients that were included in our analysis. The mean age was 52 years, of which 67% were male. All of the patients had community-acquired chronic hyponatremia. Twelve patients had an initial serum sodium <115 mEq/L, of which seven had an initial serum sodium ≤105 mEq/L. Other risk factors identified included alcohol use disorder (n=11), hypokalemia (n=5), liver disease (n=6), and malnutrition (n=11). The maximum rate of correction in patients with serum sodium <115 mEq/L was at least 8 mEq/L in all but one patient. In contrast, correction was <8 mEq/L in all but two patients with serum sodium ≥115 mEq/L. Among the latter group, osmotic demyelination syndrome developed before hospital admission or was unrelated to hyponatremia overcorrection. Four patients died (19%), five had full recovery (24%), and nine (42%) had varying degrees of residual neurologic deficits.

Conclusion

Osmotic demyelination syndrome can occur in patients with chronic hyponatremia with a serum sodium <115 mEq/L, despite rates of serum sodium correction ≤10 mEq/L in 24 hours. In patients with severe hyponatremia and high-risk features, especially those with serum sodium <115 mEq/L, we recommend limiting serum sodium correction to <8 mEq/L. Thiamine supplementation is advisable for any patient with hyponatremia whose dietary intake has been poor.

Hyponatremia and extrapontine myelinolysis in a patient with COVID-19: A case report

Until we have strong evidence to the contrary, symptomatic hyponatremia should be treated with extra caution in COVID-19 co-infection patients as the latter could be another risk factor for the development of extrapontine myelinolysis.

Uremia Preventing Osmotic Demyelination Syndrome Despite Rapid Hyponatremia Correction

Hyponatremia is the most common electrolyte abnormality encountered both in the inpatient and outpatient clinical settings in the United States. Rapid correction leads to a deranged cerebral osmotic gradient causing osmotic demyelination syndrome. Coexisting azotemia is considered to be protective against osmotic demyelination syndrome owing to its counteractive effect on osmolarity change that occurs with rapid hyponatremia correction. In this article, we report the case of a 37-year-old male who presented with altered mentation, acute azotemia, and severe electrolyte derangements, with serum blood urea nitrogen 160 mg/dL, creatinine 8.4 mg/dL, sodium 107 mEq/L, potassium 6.1 mEq/L, bicarbonate 7 mEq/L, and anion gap of 33. Given refractory hyperkalemia with electrocardiogram changes, emergent dialysis was performed. Despite our efforts to avoid rapid correction, serum sodium was corrected to 124 mEq/L and blood urea nitrogen decreased to 87 mg/dL at the end of the 5-hour dialysis session. Fortunately, hospital course and 4-week post-discharge clinic follow-ups were uncomplicated with no neurological sequela confirmed by neurological examination and magnetic resonance imaging.

[Central pontine myelinolysis during qualified alcohol withdrawal therapy. A case report]

Central pontine myelinolysis is a rare but severe disease that often occurs in alcohol-dependent and malnourished patients. One pathological mechanism is the rapid correction of chronic hyponatremia, even though the disease can occur independently of decreased serum sodium levels. Here, we present a patient suffering from malnutrition, alcohol dependency, and a severe depressive disorder, who presented himself to our clinic wishing for qualified withdrawal treatment. Because the patient reported significant weight loss and nocturnal sweating without fever, we performed different diagnostic investigations and examinations. Cranial MRI revealed the presence of a central pontine myelinolysis. In the clinical neurological examination, the patient only showed slight gait ataxia. The depressive symptoms had improved while the patient now showed problems in his short-term memory. At presentation, only slight hyponatremia was present, while no rapid correction occurred throughout treatment. The presented case reveals the importance of considering osmotic demyelination disorders as a differential diagnosis in patients suffering from neurological symptoms during alcohol withdrawal therapy. This is important independently of hyponatremia.

The Changing Face of Osmotic Demyelination Syndrome: A Retrospective, Observational Cohort Study

Objective

To describe the long-term outcomes of osmotic demyelination syndrome (ODS) in an updated cohort.

Methods

We performed a retrospective medical records review of cases of ODS at the Massachusetts General and Brigham and Women's Hospitals using International Classification of Diseases-9th edition codes and a text-based search for central pontine myelinolysis, extrapontine myelinolysis, and osmotic demyelination syndrome (1999-2018). Cases were individually selected based on patients having neuroimaging and symptoms consistent with ODS and no other potentially explanatory etiology. Modified Rankin scale (mRS) scores were extracted at prehospitalization, hospital discharge, 6 months post discharge, and the most recently available clinical visit.

Results

We identified 45 cases of ODS (mean age 48.4 years, range 0.07-75 years; 58% female patients). Common comorbidities included liver disease (27%, n = 12), alcoholism (44%, n = 20), and kidney failure (20%, n = 9). Twenty-nine percent of patients had a rapid correction of hyponatremia. Twenty-nine percent had other electrolyte abnormalities. Only 59% (24/41) of patients with complete electrolyte data had abnormalities that could explain their ODS. At the 6-month follow-up, 16% of the patients were dead and 60% of patients had minimal-to-no disability (mRS 0-2).

Conclusions

ODS has a diverse range of clinical presentations. Not all patients have electrolyte abnormalities. The prognosis is generally favorable, although 1 in 6 patients had died at 6 months, likely because of underlying disease states.

Hypertonic saline, isotonic saline, water restriction, long loops diuretics, urea or vaptans to treat hyponatremia

Introduction: Hyponatremia is the most common fluid and electrolyte abnormality. It is associated with much higher morbidity and mortality rates than found in non hyponatremic patients.Areas covered: When the physician is faced to a hyponatremic patient he first has to confirm that hyponatremia is associated with hypoosmolality. Then he must answer to a series of questions: What is its origin? Is it acute or chronic? Which treatment is the most appropriate? We will discuss the various options for the treatment of hypotonic hyponatremia. For a better comprehensive approach of the treatment we will also discuss some pathophysiological data. The use of urea in euvolemic and hypervolemic hyponatremia will be particularly discussed. Literature was reviewed from Jan 1970 to Dec 2019.Expert opinion: Prospective studies showing the benefit in decreasing morbidity by increasing SNa in patients with chronic hyponatremia should be done. These studies should also compare the efficacy and side effects of urea therapy compare to vaptans.