Hyponatremia in the emergency department

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

INTRODUCTION

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSION

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

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.

Current and Future Burdens of Heat-Related Hyponatremia: A Nationwide Register-Based Study

CONTEXT

A seasonal variation in hyponatremia, with higher incidence rates during hot summer days, has been demonstrated. Whether this applies to cool temperate regions is currently unknown.

OBJECTIVE

The aim of this study was to investigate the influence of ambient temperature on hyponatremia in the Swedish population under current and future climate scenarios.

METHODS

This nationwide cohort study identified all patients hospitalized with a first-ever principal diagnosis of hyponatremia between October 2005 and December 2014. Incidence rates for hyponatremia were calculated as number of hospitalizations divided by person-days at risk in the adult Swedish population at a given temperature, in increments of 1 °C.

RESULTS

The incidence of hyponatremia was stable at 0.3 per million person-days from -10 to 10 °C, but increased rapidly at 24-hour mean temperatures above 15 °C, with 2.26 hospitalizations per million days at the highest recorded temperature of 25 °C. Women and elderly carried the greatest risk, with an incidence of 35 hospitalizations per million days in individuals ≥ 80 years of age on the hottest days, corresponding to a 15-fold increase in incidence compared with cool days. A future 1 or 2 °C increase in mean temperature is expected to increase the incidence of hyponatremia by 6.3% and 13.9%, respectively.

CONCLUSION

The risk of hospitalization due to hyponatremia increases rapidly at temperatures above 15 °C, indicating a threshold effect. Over the next decades, rising global temperatures are expected to increase the inpatient burden of hyponatremia by approximately 10%. Strategies for protecting vulnerable groups are necessary to reduce this risk.

Risk factors and mortality in elderly patients with severe hyponatremia admitted to the emergency department

BACKGROUND

This study was aimed at determining the risk factors associated with mortality in elderly patients with severe hyponatremia admitted to the emergency department.

MATERIALS AND METHODS

The data of patients aged ≥ 65 years who were admitted to the emergency department and whose serum sodium levels were < 125 mEq/L were retrospectively collected.

RESULTS

Mortality was associated with chronic liver disease/cirrhosis (p = 0.036), metastatic tumor (p = 0.007) and solid tumor (p = 0.013) cancers, antiarrhythmic drug use (p = 0.003), potassium-sparing diuretic use (p = 0.044), antineoplastic drug use (p = 0.0029), and dialysis treatment (p = 0.015). The following cutoff values were determined to be predictive of mortality: urea > 63.6 (AUC: 0.771; p = 0.0001), creatinine > 1.39 (AUC: 0.675; p = 0.0003), potassium > 4.64 (AUC: 0.711; p = 0.0001), C-reactive protein > 44 (AUC: 0.765; p = 0.0001), white blood cell count > 12.21 (AUC: 0.688; p = 0.0001), hemoglobin < 11.2 (AUC: 0.611; p = 0.0103), and Charlson comorbidity index > 2 (AUC: 0.739; p = 0.0001). The use of antineoplastic drugs (OR: 4.502; p = 0.010) and increased values of the following were associated with an increased risk of mortality: urea (OR: 1.007; p = 0.024), C-reactive protein (OR: 1.005; p = 0.026), glucose (OR: 1.008; p = 0.001), and Charlson comorbidity index (OR: 1.198; p = 0.025).

CONCLUSION

Malignancy; liver cirrhosis; dialysis treatment; increased Charlson comorbidity index, urea, and C-reactive protein values and the use of antineoplastic drugs are associated with mortality.

High Incidence of Hyponatremia in Patients Operated for Nonsellar/Suprasellar Supratentorial Tumors—A Prospective Observational Study

Background The incidence of hyponatremia is high in supratentorial tumors. However, most studies of supratentorial tumors have included patients with sellar/suprasellar tumors. It is common knowledge that sellar tumors have higher incidence and severity of hyponatremia. Incidence of hyponatremia is not known if we exclude sellar/suprasellar tumors. Therefore, this study was designed to evaluate the incidence of hyponatremia in supratentorial tumors after excluding sellar/suprasellar tumors.

Methods After institutional ethics committee approval and written informed consent, adult patients with supratentorial tumors (nonsellar/suprasellar) were recruited, and data were collected prospectively. In all patients, serum electrolytes were measured every 2 to 3 days. Hyponatremia was defined as serum sodium of <135 mEq/L. All the patients were followed up till death or discharge from the hospital.

Results A total of 61 patients’ data were analyzed. There were 31 male and 30 female patients with an average age of 44 years. There were 23 meningiomas, 36 gliomas, and 2 other tumors. Forty patients (66%) developed hyponatremia during hospital stay. There were 29 mild cases (serum sodium 131–134 mEq/L), 7 were moderate (serum sodium 126–130 mEq/L), and 4 were severe (serum sodium <126 mEq/L). Three hyponatremic meningioma patients died, of which two had mild hyponatremia and one had severe hyponatremia. Duration of hospital stay was longer in hyponatremic patients.

Conclusion The incidence of hyponatremia is high in supratentorial tumor patients after excluding sellar/suprasellar lesions. In the majority of patients, the disturbance is mild. Hyponatremic patients has a longer hospital stay and higher mortality.

Artificial intelligence for detecting electrolyte imbalance using electrocardiography

Introduction

The detection and monitoring of electrolyte imbalance is essential for appropriate management of many metabolic diseases; however, there is no tool that detects such imbalances reliably and noninvasively. In this study, we developed a deep learning model (DLM) using electrocardiography (ECG) for detecting electrolyte imbalance and validated its performance in a multicenter study.

Methods and Results

This retrospective cohort study included two hospitals: 92,140 patients who underwent a laboratory electrolyte examination and an ECG within 30 min were included in this study. A DLM was developed using 83,449 ECGs of 48,356 patients; the internal validation included 12,091 ECGs of 12,091 patients. We conducted an external validation with 31,693 ECGs of 31,693 patients from another hospital, and the result was electrolyte imbalance detection. During internal, the area under the receiving operating characteristic curve (AUC) of a DLM using a 12‐lead ECG for detecting hyperkalemia, hypokalemia, hypernatremia, hyponatremia, hypercalcemia, and hypocalcemia were 0.945, 0.866, 0.944, 0.885, 0.905, and 0.901, respectively. The values during external validation of the AUC of hyperkalemia, hypokalemia, hypernatremia, hyponatremia, hypercalcemia, and hypocalcemia were 0.873, 0.857, 0.839, 0.856, 0.831, and 0.813 respectively. The DLM helped to visualize the important ECG region for detecting each electrolyte imbalance, and it showed how the P wave, QRS complex, or T wave differs in importance in detecting each electrolyte imbalance.

Conclusion

The proposed DLM demonstrated high performance in detecting electrolyte imbalance. These results suggest that a DLM can be used for detecting and monitoring electrolyte imbalance using ECG on a daily basis.

Transient seizure-induced sodium increase camouflaging a symptomatic hyponatremia

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

The prevalence of dysnatremia in the elderly patients without CKD

INTRODUCTION

Dysnatremia is one of the most commonly encountered electrolyte disorders in the emergency department (ED). Few studies have reported the prevalence of dysnatremia in elderly patients without chronic kidney disease (CKD). We investigated the prevalence of dysnatremia in elderly patients without CKD in an emergency department in Japan.

METHODS

We reviewed 10,558 patients presenting to the ED between July 2015 and December 2017. The adult group consisted of 4562 patients aged between 18 and 64 years old, and the elderly group consisted of 5996 patients aged over 65 years. Information collected included age, gender, serum sodium and serum creatinine. Hyponatremia was defined as serum sodium level < 135 mEq/L, and severe hyponatremia was defined as a serum sodium level < 125 mEq/L. Hypernatremia was defined as a serum sodium level > 145 mEq/L, and moderate to severe hypernatremia was defined as a serum sodium level ≧ 150 mEq/L.

RESULTS

In the adult group, the prevalence of hyponatremia was 2.8% in patients without CKD and 10.3% in patients with CKD (P < 0.001). On the other hand, in the elderly group, the prevalence of hyponatremia was 14.8% in patients without CKD and 12.9% in patients with CKD (P = 0.034). In the adult group, the prevalence of hypernatremia was 0.7% in patients without CKD and 2.0% in patients with CKD (P = 0.003). Similarly, in the elderly group, the prevalence of hypernatremia was 1.5% in patients without CKD and 3.5% in patients with CKD (P < 0.001).

CONCLUSION

In elderly patients, the prevalence of hyponatremia was higher in patients without CKD than in patients with CKD. Special attention should be paid to elderly patients without CKD in order to prevent severe hyponatremia.

Seasonal prevalence of hyponatremia in the emergency department: impact of age

Background

Hyponatremia is one of the most commonly encountered electrolyte disorders in emergency department (ED). Seasonal fluctuations of the prevalence of hyponatremia has been reported. We investigated the impact of age on the seasonal prevalence of hyponatremia in the emergency department in Japan.

Methods

Total of 8377 patients presented to the ED between January 2015 and December 2016 were reviewed. The adult group aged between 18 and 64 years old consisted of 3656 patients and the elderly group aged over 65 years consisted of 4721 patients. Information collected included age, sex, serum sodium, and serum creatinine. Hyponatremia was defined as a serum sodium leve1 < 135 mEq/L and severe hyponatremia was defined as a serum sodium level < 125 mEq/L.

Results

Prevalence of hyponatremia was significantly higher in the elderly group than in the adult group (17.0% vs. 5.7%, p < 0.001). Similarly, the prevalence of severe hyponatremia was significantly higher in the elderly group than in the adult group (1.9% vs. 0.3%, p < 0.001). Prevalence of hyponatremia and severe hyponatremia was significantly higher in the elderly group than in the adult group in all seasons. In the elderly group, there was a significant correlation between weather high temperature during summer and prevalence of hyponatremia (r = 0.510, p = 0.011).

Conclusion

There was a major impact of age on the seasonal prevalence of hyponatremia and severe hyponatremia. Strategies to prevent hyponatremia and severe hyponatremia should be taken especially in the elderly patients during summer.

Mortality rates are lower in SIAD, than in hypervolaemic or hypovolaemic hyponatraemia: Results of a prospective observational study

OBJECTIVE

Hyponatraemia is associated with increased mortality, but the mortality associated specifically with SIAD is not known. We hypothesized that mortality in SIAD was elevated, but that it was less than in hypervolaemic (HEN) or hypovolaemic (HON) hyponatraemia.

DESIGN

Mortality rates are presented as risk ratios (RR),with 95% confidence intervals (CI), and compared to normonatraemic controls (NN).

METHODS

Prospective, single centre, noninterventional study of all patients with hyponatraemia (≤130 mmol/L) admitted to hospital.

RESULTS

A total of 1323 admissions with hyponatraemia were prospectively evaluated and 1136 contemporaneous NN controls. 431(32.6%) hyponatraemic patients had HON, 573(43.3%) had SIAD and 275(20.8%) patients had HEN. In patient mortality was higher in hyponatraemia than NN (9.1% vs 3.3%, P<.0001). The RRs for in-hospital mortality compared to NN were: SIAD, 1.76 (95% CI 1.08-2.8, P=.02), HON 2.77 (95% CI 1.8-4.3, P<.0001) and HEN, 4.9 (95% CI 3.2-7.4, P<.0001). The mortality rate was higher in HEN (RR 2.85; 95% CI 1.86-4.37, P<.0001) and in HON, (RR 1.6; 95% CI 1.04-2.52; P=.03), when compared to SIAD. The Charlson Comorbidity Index was lower in SIAD than in eunatraemic patients (P<.0001). 9/121(7.4%) patients died with plasma sodium <125 mmol/L and 4(3.3%) with plasma sodium <120 mmol/L. However, 69/121(57%) patients died with a plasma sodium above 133 mmol/L.

CONCLUSIONS

We confirmed higher all-cause mortality in hyponatraemia than in NN. Mortality was higher in SIAD than in normonatraemia and was not explained on the basis of co-morbidities. Mortality was higher in HON and HEN than in SIAD. Mortality rates reported for all-cause hyponatraemia in the medical literature are not applicable to SIAD.

Predictors of Post-discharge Mortality Among Patients Hospitalized for Acute Heart Failure

Acute Heart Failure (AHF) is a " multi-event disease" and hospitalisation is a critical event in the clinical course of HF. Despite relatively rapid relief of symptoms, hospitalisation for AHF is followed by an increased risk of death and re-hospitalisation. In AHF, risk stratification from clinically available data is increasingly important in evaluating long-term prognosis. From the perspective of patients, information on the risk of mortality and re-hospitalisation would be helpful in providing patients with insight into their disease. From the perspective of care providers, it may facilitate management decisions, such as who needs to be admitted and to what level of care (i.e. floor, step-down, ICU). Furthermore, risk-stratification may help identify patients who need to be evaluated for advanced HF therapies (i.e. left-ventricle assistance device or transplant or palliative care), and patients who need early a post-discharge follow-up plan. Finally, risk stratification will allow for more robust efforts to identify among risk markers the true targets for therapies that may direct treatment strategies to selected high-risk patients. Further clinical research will be needed to evaluate if appropriate risk stratification of patients could improve clinical outcome and resources allocation.

When plenty is too much: water intoxication in a patient with a simple urinary tract infection

Healthcare professionals frequently advise patients with simple infective illness to drink more fluids. Here, a 59-year-old woman with a urinary tract infection followed such advice resulting in hospital admission with symptomatic acute hyponatraemia. Water intoxication is well recognised as a cause of symptomatic hyponatraemia in endurance sports, MDMA use and psychogenic polydipsia. It has rarely been described outside of these circumstances. With normal renal function, it is difficult to overwhelm the excretory capacity for water. However, in infective illness, increased levels of antidiuretic hormones (which may be secreted both appropriately to correct volume status and inappropriately as a feature of disease) reduce renal excretion of water. In this scenario, could increased administration of oral hypotonic fluids lead to hyponatraemia, with associated morbidity and mortality, than has previously been recognised? There is a need for more research to qualify our oft-given advise to drink more fluids.

Electrolyte and mineral disturbances in septic acute kidney injury patients undergoing continuous renal replacement therapy

Electrolyte and mineral disturbances remain a major concern in patients undergoing continuous renal replacement therapy (CRRT); however, it is not clear whether those imbalances are associated with adverse outcomes in patients with septic acute kidney injury (AKI) undergoing CRRT. We conducted a post-hoc analysis of data from a prospective randomized controlled trial. A total of 210 patients with a mean age of 62.2 years (136 [64.8%] males) in 2 hospitals were enrolled. Levels of sodium, potassium, calcium, and phosphate measured before (0 hour) and 24 hours after CRRT initiation. Before starting CRRT, at least 1 deficiency and excess in electrolytes or minerals were observed in 126 (60.0%) and 188 (67.6%) patients, respectively. The excess in these parameters was greatly improved, whereas hypokalemia and hypophosphatemia became more prevalent at 24 hours after CRRT. However, 1 and 2 or more deficiencies in those parameters at the 2 time points were not associated with mortality. However, during 28 days, 89 (71.2%) deaths occurred in patients with phosphate levels at 0 hour of ≥4.5 mg/dL as compared with 49 (57.6%) in patients with phosphate levels <4.5 mg/dL. The 90-day mortality was also significantly higher in patients with hyperphosphatemia. Similarly, in 184 patients who survived at 24 hours after CRRT, hyperphosphatemia conferred a 2.2-fold and 2.6-fold increased risk of 28- and 90-day mortality, respectively. The results remained unaltered when the serum phosphate level was analyzed as a continuous variable. Electrolyte and mineral disturbances are common, and hyperphosphatemia may predict poor prognosis in septic AKI patients undergoing CRRT.

Diseases associated with electrolyte imbalance in the ED: age-related differences

OBJECTIVE

The objective of the study is to investigate the prevalence of electrolyte imbalance (EI) in the emergency department (ED) with systemic diseases in different decades of life.

METHODS

We enrolled patients admitted to the ED. The population study included 7941 patients, subdivided in 3 groups: young group (Y), middle-aged group (MA), and elderly group (E).

RESULTS

We observed EI in 13.7% of the whole population. Hyponatremia (hNa⁺) is the most frequent EI (44%) followed by hypokalemia (hK⁺) (39%), hyperkalemia (HK⁺) (13%), and hypernatremia (HNa⁺) (4.4%). In the Y group, the EI occurred in 7.1% of all patients (P< .05 vs MA and E), whereas in the MA group, they were shown in 11.5% of patients and in the E group in 22% of all patients group (P< .05 vs MA and Y). In the Y group, gastrointestinal diseases are the most frequently associated disease (24.6%; P< .05 vs MA and E). In the MA group, the most frequently associated disease was a current cardiovascular disease (29.7%; P< .05 vs Y and E). In the E group, the frequently associated diseases are cardiovascular (22.8%; P< .05 vs Y) and lung diseases (16.7%; P< .05 vs MA and Y).

CONCLUSIONS

In our study, 13.7% of all patients showed an EI, and only 2% of cases were alone without any associated systemic disease. Most EIs are associated to other systemic diseases. The present data also depict different age-related and disease-associated prevalence patterns of EI, thus highlighting a complex clinical scenario.

The burden of illness in patients with hyponatraemia in Sweden: a population-based registry study

BACKGROUND

Hyponatraemia (HN; serum sodium level < 135 mmol/l) is the most common electrolyte disturbance seen in clinical practice, and is associated with varying spectrum of symptoms. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common aetiology in hospitalised patients, and can be caused by several different underlying conditions.

AIMS

The objectives of this study were to retrospectively examine the baseline characteristics, clinical outcomes and hospital resource utilisation of patients with HN and/or SIADH in Sweden over a 10-year period from 2001 to 2011. Additional analysis was performed on subpopulations of patients with hip fracture, pneumonia and small cell lung cancer (SCLC) to see if trends in outcomes were consistent across a broad range of aetiologies commonly associated with the condition.

METHODS

Patient information was taken from the Swedish National Patient Registry, the Swedish Cancer Registry, the Swedish Cause of Death Register and the Swedish Prescribed Drug Register. A total of 34,537 patients (4.38%) were identified with HN and/or SIADH, with the incidence and prevalence rising over the 10-year study period.

RESULTS

Of the 34,537 patients identified, 841 had hip fracture, 2635 had pneumonia and 106 had SCLC. Compared with matched control patients, those with HN and/or SIADH had a longer length of hospital stay, a higher re-admission rate and a shorter time to re-admission.

CONCLUSIONS

This study showed that HN and/or SIADH negatively impact patient outcomes and healthcare resources related to hospital stay irrespective of the underlying cause. The impact of HN is not confined to the initial hospitalisation, as re-admission rates are also affected.

Patterns of intensive care unit admissions in patients hospitalized for heart failure: insights from the RO-AHFS registry

AIM

The present study aims to describe the epidemiology, baseline clinical characteristics, in-hospital management, and outcome of patients hospitalized for heart failure admitted directly or transferred to the ICU.

METHODS AND RESULTS

The Romanian Acute Heart Failure Syndromes (RO-AHFS) registry prospectively enrolled 3224 consecutive patients between January 2008 and May 2009 admitted with a primary diagnosis of heart failure. Participants were classified by ICU admission status (i.e. ICU+/ICU-). Independent clinical predictors of ICU admission and in-hospital mortality were identified using multivariable logistic regression analysis. Overall, 10.7% of patients required ICU level care, 32% as a direct ICU admission, with 68% as an ICU transfer during hospitalization. Patients admitted to the ICU had a mean age of 68.1 ± 11.3 years, 61% were men, 67% had an ischemic cause, and 44% presented with de-novo heart failure. ICU+ patients more frequently presented with low SBP and pulse pressure and abnormal renal function. Mechanical ventilation was required in 32.7% and intravenous inotropes were administered to 56.7% of ICU+ patients. ICU+ patients had higher in-hospital mortality compared to ICU- patients (17.3 vs. 6.5%). Patients admitted directly to the ICU had a 15.3% mortality rate compared to 18.4% in those transferred after admission. Age, serum sodium, SBP below 110 mmHg, and left-ventricular ejection fraction less than 45% were predictive of ICU admission, whereas for ICU+ patients, age, vasopressor, and mechanical ventilation utilization were predictive of mortality.

CONCLUSIONS

Patients admitted directly or transferred to the ICU are at a high risk of in-hospital mortality. Clinical variables commonly measured at the time of admission may facilitate disposition decision-making including early triage to the ICU.

Incidence, Severity and Prognosis Associated with Hyponatremia in Dogs and Cats

Background

Hyponatremia is a common electrolyte abnormality in human patients and is associated with substantial morbidity and death. The incidence and importance of hyponatremia in dogs and cats has not been determined.

Hypothesis/Objectives

To describe the incidence of and prognosis associated with hyponatremia in dogs and cats at a university teaching hospital.

Animals

Of 16,691 dogs and 4,211 cats with measured blood or serum sodium concentration.

Methods

Retrospective study. Medical records of animals with a blood or serum sodium concentration measured during a 60‐month period were reviewed to determine the severity of hyponatremia and its associated fatality rate. Cases with moderate (11–15 mmol/L below the reference range) or severe hyponatremia (≥16 mmol/L below the reference range) were further reviewed.

Results

Of 4,254 dogs (25.5%) and 2,081 cats (49.4%) were diagnosed with hyponatremia. Case fatality rates of dogs and cats with hyponatremia were 13.7% and 11.9%, respectively, compared to 4.4% and 4.5% with a normal blood or serum sodium concentration (P < 0.0001). The magnitude of hyponatremia was linearly associated with a higher case fatality rate (P < 0.0001). Hyponatremia was associated with a lower case fatality rate than hypernatremia in the same population. Among the animals with moderate or severe hyponatremia, 92.1% of dogs and 90.6% of cats presented with community‐acquired hyponatremia, and 7.9% of dogs and 9.4% of cats developed hospital‐acquired hyponatremia.

Conclusions and clinical importance

Hyponatremia was found commonly in this population and was associated with increased case fatality rate. Presence and severity of hyponatremia might be useful as a prognostic indicator.

General characteristics of patients with electrolyte imbalance admitted to emergency department

BACKGROUND:

Fluid and electrolyte balance is a key concept to understand for maintaining homeostasis, and for a successful treatment of many metabolic disorders. There are various regulating mechanisms for the equilibrium of electrolytes in organisms. Disorders of these mechanisms result in electrolyte imbalances that may be life-threatening clinical conditions. In this study we defined the electrolyte imbalance characteristics of patients admitted to our emergency department.

METHODS:

This study was conducted in the Emergency Department (ED) of Uludag University Faculty of Medicine, and included 996 patients over 18 years of age. All patients had electrolyte imbalance, with various etiologies other than traumatic origin. Demographic and clinical parameters were collected after obtaining informed consent from the patients. The ethical committee of the university approved this study.

RESULTS:

The mean age of the patients was 59.28±16.79, and 55% of the patients were male. The common symptoms of the patients were dyspnea (14.7%), fever (13.7%), and systemic deterioration (11.9%); but the most and least frequent electrolyte imbalances were hyponatremia and hypermagnesemia, respectively. Most frequent findings in physical examination were confusion (14%), edema (10%) and rales (9%); and most frequent pathological findings in ECG were tachycardia in 24%, and atrial fibrillation in 7% of the patients. Most frequent comorbidity was malignancy (39%). Most frequent diagnoses in the patients were sepsis (11%), pneumonia (9%), and acute renal failure (7%).

CONCLUSIONS:

Electrolyte imbalances are of particular importance in the treatment of ED patients. Therefore, ED physicians must be acknowledged of their fluid-electrolyte balance dynamics and general characteristics.

Recurrent hospitalizations with moderate to severe hyponatremia in older adults and its associated mortality

BACKGROUND

Recurrent hospitalizations with hyponatremia are commonly encountered in older adults admitted to Internal Medicine wards. However, the incidence and the prognostic implication of this phenomenon have never been studied.

METHODS

Medical charts of all older adults (≥75 years) admitted to Internal Medicine wards at a tertiary medical center during 2009-2010 with symptomatic moderate to severe hyponatremia (blood sodium ≤130 meq/l) upon admission were reviewed. The study group included patients with one or more hospitalizations with hyponatremia in the year following the first hospitalization with hyponatremia. The control group included patients with a single hospitalization with hyponatremia. Mortality rates were studied one year following the second hospitalization with hyponatremia in the study group and one year following the single hospitalization with hyponatremia in the control group. Regression analysis was used to study the association between recurrent hospitalizations with hyponatremia and 1-year mortality while controlling for demographics, chronic co-morbidities, albumin serum levels, and the number of hospitalizations.

RESULTS

The cohort included 431 older adults: 301 (69.8%) women; mean age of 84.6±5.6 years. Overall, 120 (27.8%) patients had recurrent hospitalizations with hyponatremia and 125 (29.0%) patients died within a year. 1-Year mortality rates were higher in patients with recurrent hospitalizations with hyponatremia than in patients with a single hospitalization with hyponatremia (42.5% vs. 23.8%; p<0.0001). Regression analysis showed that recurrent hospitalizations with hyponatremia were independently associated with 1-year mortality (odds ratio 1.9; 95% confidence interval 1.1-3.2; p=0.018).

CONCLUSIONS

Recurrent hospitalizations with hyponatremia in older adults are common and associated with 1-year mortality.

Hyponatraemia is an independent predictor of in-hospital mortality

BACKGROUND

Hyponatraemia increases morbidity and mortality, but the extent to which this condition influences mortality independently of other contributing factors is unclear.

MATERIALS AND METHODS

All hyponatremic patients admitted to the internal medicine department during a six month period were included. Medical records were reviewed and patients' demographics, underlying disease, cause of hyponatremia and in-hospital deaths were noted. Control group consisted of patients with normonatremia admitted to the same department during the same period matched 1:1 by sex, age and underlying disease. Difference in in-hospital mortality rate between the study and control groups was tested by chi-square test. Baseline demographics, underlying diseases, cause of hyponatremia and state of hyponatremia correction as possible risk factors for mortality were tested in a multivariate analysis.

RESULTS

The baseline cohort of all admitted patients consisted of 2,171 patients. Hyponatraemia was found in 278 (13%) patients (160 females and 118 males). The three most common causes of hyponatremia included gastrointestinal loss (52 patients), decreased oral intake (47 patients), and dilution hyponatremia (45 patients). The in-hospital mortality rate in the hyponatremic group was significantly higher compared with the control group (22% vs 7%, respectively; OR 3.75, 95% CI 2.17-6.48, p<0.0001). In a multivariate analysis age above 65 years, dilution hyponatremia, decreased oral intake as etiologic factors of hyponatremia, and unsuccessful hyponatremia correction were independent factors associated with increased mortality.

CONCLUSION

Hyponatraemia represents independent factor associated with in-hospital mortality. Age above 65 years, failure to correct hyponatremia and some specific etiologic factors of hyponatremia are related to increased mortality.

Disorders of sodium and water balance

Dysnatremias occur simultaneously with disorders in water balance. The first priority is to correct dehydration; once the patient is euvolemic, the sodium level can be reassessed. In unstable patients with hyponatremia, the clinician should rapidly administer hypertonic saline. In unstable patients with hypernatremia, the clinician should administer isotonic intravenous fluid. In stable patients with either hyponatremia or hypernatremia, the clinician should aim for correction over 24 to 48 hours, with the maximal change in serum sodium between 8 to 12 mEq/L over the first 24 hours. This rate of correction decreases the chances of cerebral edema or osmotic demyelination syndrome.

Randomized, double-blind trial of the effect of fluid composition on electrolyte, acid-base, and fluid homeostasis in patients early after subarachnoid hemorrhage

BACKGROUND

Hyper- and hyponatremia are frequently observed in patients after subarachnoidal hemorrhage, and are potentially related to worse outcome. We hypothesized that the fluid regimen in these patients is associated with distinct changes in serum electrolytes, acid-base disturbances, and fluid balance.

METHODS

Thirty-six consecutive patients with SAH were randomized double-blinded to either normal saline and hydroxyethyl starch dissolved in normal saline (Voluven(®); saline) or balanced crystalloid and colloid solutions (Ringerfundin(®) and Tetraspan(®); balanced, n = 18, each) for 48 h. Laboratory samples and fluid balance were evaluated at baseline and at 24 and 48 h.

RESULTS

Age [57 ± 13 years (mean ± SD; saline) vs. 56 ± 12 years (balanced)], SAPS II (38 ± 16 vs. 34 ± 17), Hunt and Hess [3 (1-4) (median, range) vs. 2 (1-4)], and Fischer scores [3.5 (1-4) vs. 3.5 (1-4)] were similar. Serum sodium, chloride, and osmolality increased in saline only (p ≤ 0.010, time-group interaction). More patients in saline had Cl >108 mmol/L [16 (89 %) vs. 8 (44 %); p = 0.006], serum osmolality >300 mosmol/L [10 (56 %) vs. 2 (11 %); p = 0.012], a base excess <-2 [12 (67 %) vs. 2 (11 %); p = 0.001], and fluid balance >1,500 mL during the first 24 h [11 (61 %) vs. 5 (28 %); p = 0.046]. Hyponatremia and hypo-osmolality were not more frequent in the balanced group.

CONCLUSIONS

Treatment with saline-based fluids resulted in a greater number of patients with hyperchloremia, hyperosmolality, and positive fluid balance >1,500 mL early after SAH, while administration of balanced solutions did not cause more frequent hyponatremia or hypo-osmolality. These results should be confirmed in larger studies.

Acute kidney injury, sodium disorders, and hypercalcemia in the aging kidney: diagnostic and therapeutic management strategies in emergency medicine

This article summarizes the current literature regarding the structural and functional changes of the aging kidney and describes how these changes make the older patient more susceptible to acute kidney injury and fluid and electrolyte disorders. It discusses the clinical manifestations, evaluation, and management of hyponatremia and shows how the management of hypernatremia in geriatric patients involves addressing the underlying cause and safely correcting the hypernatremia. The current literature regarding evaluation and management of hypercalcemia in older patients is summarized. The management of severe hypercalcemia is discussed in detail. The evaluation and management of acute kidney injury is described.

Epidemiology and characteristics of hyponatremia in the emergency department

BACKGROUND

Hyponatremia is the most common electrolyte abnormality and it is associated with increased morbidity and mortality. The aim of the study was to investigate the underlying causes and management of hyponatremia in an unselected population presenting with hyponatremia to the emergency department.

METHODS

A descriptive, retrospective hospital record study was performed. A database search was conducted for all patients presenting to the emergency departments in Lund and Malmo and patients with a P-Na-value<135mmol/L were identified. Patients were divided into four groups based on the severity of hyponatremia (Group 1: P-Na<120mM, Group 2: Na 120-124mM, Group 3: Na 125-129mM, Group 4: Na 130-134mM) and 100 patients from each group were included. Groups 2-4 were matched to Group 1 for age, gender and month for ER visit.

RESULTS

The prevalence of hyponatremia (P-Na<135mmol/L) was 3% in the entire emergency population. A single underlying cause was identified in 45% of patients in Group 1. The leading aetiologies were thiazide diuretics (17%), SIADH (17%) and other diuretics (14%). The likelihood of being on thiazide diuretics increased with hyponatremia severity (p<0.0001) and patients in Group 1 were 3.6 times (CI95%:1.9-6.8) more likely to be on thiazide diuretics compared to Group 4. The in-hospital mortality ranged between 2 and 7% between the groups (NS). One patient developed osmotic demyelinisation syndrome but survived. Only 31% of patients in Group 1 were evaluated with a basic laboratory investigation.

CONCLUSIONS

Thiazide diuretics and SIADH were dominating underlying causes of hyponatremia, however, the frequency of adequate diagnostic testing was low. The majority of patients were treated with sodium chloride infusion.

Prevalence of hyponatremia on geriatric wards compared to other settings over four decades: a systematic review

Aim of the study was to analyze temporal trends in prevalence of hyponatremia over four decades in different settings. A systematic review of the literature from 1966 to 2009 yielded prevalences of hyponatremia, with standard errors (SE) and pooled estimated means (PEM), calculated by year and setting (geriatric, ICU, other hospital wards, psychiatric hospitals, nursing homes, outpatients). 53 studies were included. Prevalence of hyponatremia was stable from 1976 to 2006, and higher on geriatric wards accept for ICU: e.g. PEM prevalence of mild hyponatremia (serum sodium <135 mM) was 22.2% (95%CI 20.2-24.3) on geriatric wards, 6.0% (95%CI 5.9-6.1) on other hospital wards and 17.2% (SE 7.0) in one ICU-study; for severe hyponatremia (serum sodium<125 mM) these figures were 4.5% (95%CI 3.0-6.1), 0.8% (95%CI 0.7-0.8) and 10.3% (SE 5.6). In nursing homes PEM prevalence of mild hyponatremia was 18.8% (95%CI 15.6-22.2). The higher prevalence on geriatric wards could partly be explained by age-related changes in the regulation of serum sodium. Other underlying factors can be the presence of multiple diagnoses and the use of polypharmacy.

Characteristics, symptoms, and outcome of severe dysnatremias present on hospital admission

OBJECTIVE

Dysnatremias are common in critically ill patients and associated with adverse outcomes, but their incidence, nature, and treatment rarely have been studied systematically in the population presenting to the emergency department. We conducted a study in patients presenting to the emergency department of the University of Bern.

METHODS

In this retrospective case series at a university hospital in Switzerland, 77,847 patients admitted to the emergency department between April 1, 2008, and March 31, 2011, were included. Serum sodium was measured in 43,911 of these patients. Severe hyponatremia was defined as less than 121 mmol/L, and severe hypernatremia was defined as less than 149 mmol/L.

RESULTS

Hypernatremia (sodium>145 mmol/L) was present in 2% of patients, and hyponatremia (sodium<135 mmol/L) was present in 10% of patients. A total of 74 patients had severe hypernatremia, and 168 patients had severe hyponatremia. Some 38% of patients with severe hypernatremia and 64% of patients with hyponatremia had neurologic symptoms. The occurrence of symptoms was related to the absolute elevation of serum sodium. Somnolence and disorientation were the leading symptoms in hypernatremic patients, and nausea, falls, and weakness were the leading symptoms in hyponatremic patients. The rate of correction did not differ between symptomatic and asymptomatic patients. Patients with symptomatic hypernatremia showed a further increase in serum sodium concentration during the first 24 hours after admission. Corrective measures were not taken in 18% of hypernatremic patients and 4% of hyponatremic patients.

CONCLUSIONS

Dysnatremias are common in the emergency department. Hyponatremia and hypernatremia have different symptoms. Contrary to recommendations, serum sodium is not corrected more rapidly in symptomatic patients.

Significance of hypo- and hypernatremia in chronic kidney disease

Both hypo- and hypernatremia are common conditions, especially in hospitalized patients and in patients with various comorbid conditions such as congestive heart failure or liver cirrhosis. Abnormal serum sodium levels have been associated with increased mortality in numerous observational studies. Patients with chronic kidney disease (CKD) represent a group with a high prevalence of comorbid conditions that could predispose to dysnatremias. In addition, the failing kidney is also characterized by a gradual development of hyposthenuria, and even isosthenuria, which results in further predisposition to the development of hypo- and hypernatremia in those with advancing stages of CKD. To date, there has been a paucity of population-wide assessments of the incidence and prevalence of dysnatremias, their clinical characteristics and the outcomes associated with them in patients with various stages of CKD. We review the physiology and pathophysiology of water homeostasis with special emphasis on changes occurring in CKD, the outcomes associated with abnormal serum sodium in patients with normal kidney function and the results of recent studies in patients with various stages of CKD, which indicate a substantial incidence and prevalence and significant adverse outcomes associated with dysnatremias in this patient population.

Evaluation of prognostic value of selected biochemical markers in surgically treated patients with acute mediastinitis

BACKGROUND

Monitoring of biochemical markers of inflammation in acute mediastinitis (AM) can be useful in the modification of treatment. This study was a retrospective evaluation of selected biochemical parameters with negative impact on the prognosis in surgically treated patients.

MATERIAL/METHODS

There were 44 consecutive patients treated surgically due to AM of differentiated etiology. Selected biochemical markers (WBC, RBC, HGB, HCT, PLT, CRP, PCT, ionogram, protein and albumins) were assessed before surgery and on the 3rd day after surgery. ANOVA was applied to find factors influencing observations. Numerical data [laboratory parameters] were compared by means of medians.

RESULTS

The overall hospital mortality rate was 31.82%. In the group of dead patients, there were observed statistically significant lower mean preoperative values of RBC [p=0.0090], HGB [p=0.0286], HCT [p=0.0354], protein [p= 0.0037], albumins [p=0.0003] and sodium [p<0.0001] and elevated values of CRP [P=0.0107] and PCT p<0.0001]. High level of inflammatory markers on day 3 after surgery was found to increase the risk of death - for WBC (by 67%), for CRP (by 88%) and for PCT (by 100%).

CONCLUSIONS

Poor prognosis was more frequent in patients with preoperative high levels of CRP, PCT, anemia, hypoproteinemia and hyponatremia. The risk of death increases significantly if in the immediate postoperative period no distinct decrease in WBC count and of the CRP and PCT level is observed. In such a situation the patients should be qualified earlier for broadened diagnostic workup and for reoperation.

Hyponatremia, hypernatremia, and mortality in patients with chronic kidney disease with and without congestive heart failure

BACKGROUND

Hyponatremia is common in patients with conditions such as congestive heart failure and is associated with increased mortality in hospitalized patients. Congestive heart failure is common in patients with chronic kidney disease, but the association of serum sodium concentration with mortality in such patients is not well characterized.

METHODS AND RESULTS

We examined the association of serum sodium concentration with all-cause mortality in a nationally representative cohort of 655 493 US veterans with non-dialysis-dependent chronic kidney disease (95 961 [15%] of them with congestive heart failure). Associations were examined in time-dependent Cox models with adjustment for potential confounders. During a median follow-up of 5.5 years, a total of 193 956 patients died (mortality rate, 62.5/1000 patient-years; 95% confidence interval, 62.2-62.8). The association of serum sodium level with mortality was U-shaped, with the lowest mortality seen in patients with sodium level of 140 mEq/L and with both lower and higher levels showing significant associations with increased mortality. Patients with serum sodium levels of <130, 130 to 135.9, 145.1 to 150, and ≥150 mEq/L compared with 136 to 145 mEq/L had multivariable-adjusted mortality hazard ratios (95% confidence interval) of 1.93 (1.83-2.03), 1.28 (1.26-1.30), 1.33 (1.28-1.38), and 1.56 (1.33-1.83) (P<0.001 for all). The associations remained consistent in subgroups of patients with and without congestive heart failure.

CONCLUSIONS

Both lower and higher serum sodium levels are independently associated with higher mortality in patients with non-dialysis-dependent chronic kidney disease, irrespective of the presence or absence of congestive heart failure.

Dysnatraemias in the emergency room: Undetected, untreated, unknown?

BACKGROUND

Hypo- and hypernatraemia are the most common electrolyte disorders in hospitalized patients and have been associated with increased mortality. However, data on the prevalence of dysnatraemias in the emergency room and the characteristics of patients presenting with them are rare.

METHODS

In this retrospective study, we analyzed data from patients who presented to the emergency department of a large tertiary university hospital between September 1st 2010 and November 30th 2010 and who received measurement of serum sodium.

RESULTS

3,182 patients received measurement of serum sodium during the three-month study period. 124 patients (4%) presented with hyponatraemia on admission to the emergency department while 400 patients (13%) presented with hypernatraemia. While there was no difference in age between patients with hypernatraemia and those who were normonatraemic, patients with hyponatraemia were significantly older.

CONCLUSION

Dysnatraemias are present in almost 1 in 5 patients who presented to the emergency department. Contrarily to patients who are already hospitalized, hypernatraemia was by far more common than hyponatraemia in patients at the emergency department. Surprisingly, patients with hyponatraemia were significantly older than normonatraemic patients while there was no age difference in hypernatraemic patients. Dysnatraemias are common in the emergency room and further studies are indicated to evaluate the causes and the impact on outcome of patients.

Conivaptan: a step forward in the treatment of hyponatremia?

Hyponatremia is one of the most common electrolyte abnormalities linked to adverse outcomes and increased mortality in hospitalized patients. While the differential diagnosis for hyponatremia is diverse, most cases stem from arginine vasopressin (AVP) dysregulation, where hypoosmolality fails to suppress AVP synthesis and release. The physiological effects of AVP are currently known to depend on its interaction with any of 3 receptor subtypes V1A, V2, and V1B. Activation of V2 by AVP is the key in renal water regulation and maintenance of total body volume and plasma tonicity. Despite the long-recognized problem with excess AVP in euvolemic and hypervolemic hyponatremia, traditional therapeutic options have relied on nonspecific and potentially problematic strategies. More recently, a new class of drugs, introduced as “aquaretics,” has gained great attention among clinicians because of its ability to correct hyponatremia via direct competitive inhibition of AVP at V2 receptors to induce renal electrolyte-free water excretion. In this paper, we aim to review available clinical data on the only FDA-approved aquaretic, dual V1A/V2 receptor antagonist conivaptan, discuss its clinical indications, efficacy, safety profile, and comment on its clinical limitations.

Study of outcomes associated with hyponatremia and hypernatremia in children

Sodium is usually included in hospitals' critical values lists; however, the values at which sodium is considered to be life threatening (critical) vary among hospitals. Studies of outcomes associated with hyponatremia and hypernatremia in pediatric patients have not been published. We performed a retrospective chart review of sodium values of <124 mmol/L and >155 mmol/L that occurred during a 6-month period. Univariate and multivariate analyses for mortality risk were performed with the different variables. A total of 702 (1.32%) sodium tests fell in the study reference range, with 166 being <124 mmol/L and 536 being >155 mmol/L. Although not statistically significant, mortality was higher (38.5%) in patients with sodium values ≤ 120 mmol/L than in those with values ≥ 170 mmol/L (25%) or in patients with other values (<14%). Underlying conditions prevented assessment of morbidity associated with hyponatremia or hypernatremia. Treatment was instituted within 4 hours in 80% of cases (50% within 1 hour). Multivariate analysis showed increased risk of death for hyponatremic patients if they were premature or had heart abnormalities, while for hypernatremic patients the risk increased when other critical values were present. In conclusion, sodium levels of ≤ 120 mmol/L and ≥ 170 mmol/L have increased mortality in children; however, the risk of death is not statistically different when compared to risk in patients with milder hyponatremia and hypernatremia. Risk factors for death in hyponatremic and hypernatremic patients may primarily reflect the severity of the underlying conditions present in these children, such as prematurity and heart abnormalities, rather than the sodium derangement.

Hyponatremia and risk of seizures: a retrospective cross-sectional study

This retrospective cross-sectional study was carried out to study the association between different levels of hyponatremia and the occurrence of epileptic seizures in patients without a prior epilepsy diagnosis. We identified from the hospital database, 363 inpatients of a Swedish County hospital who between March 2003 and August 2006 were found to have serum sodium levels <125 mM. Medical records were reviewed and we identified 11 patients with seizures in conjunction with their hyponatremia. Seizures were the only neurologic manifestation of hyponatremia in patients with serum sodium levels >115 mM. Of 150 patients reviewed with serum sodium levels of 120-124 mM, one had a seizure. Using 120-124 mM as reference, odds ratios (95% confidence interval) for having seizures at serum sodium levels of 115-119 mM was 3.85 (0.40-37.53), 8.43 (0.859-82.85) at 110-114 mM, and 18.06 (1.96-166.86) at <110 mM.

Epidemiology of hyponatremia

Hyponatremia is the most common electrolyte abnormality encountered in clinical practice with wide-ranging prognostic implications in a variety of conditions. This review summarizes the available literature on the epidemiology of hyponatremia in both hospitalized and ambulatory-based patients. Particular attention is given to hyponatremia in the geriatric population, drug-induced hyponatremia, exercise-associated hyponatremia, and the medical costs of hyponatremia. The frequency and outcomes of hyponatremia in congestive heart failure, cirrhosis, pneumonia, and human immunodeficiency virus infection also are reviewed. Although the knowledge on hyponatremia has expanded in the past few decades, the disorder largely remains an underdiagnosed condition. Substantial additional work is needed to improve the awareness of hyponatremia among medical professionals. The advent of vasopressin-receptor antagonists as a plausible treatment option for some forms of euvolemic and hypervolemic hyponatremia now offers the opportunity to gain further insights into the prognostic impact of hyponatremia and its management in various clinical settings.

Electrolyte complications of malignancy

A thorough working knowledge of the diagnosis and treatment of life-threatening electrolyte abnormalities in cancer patients, especially hyponatremia, hypoglycemia, and hypercalcemia, is essential to the successful practice of emergency medicine. Although most minor abnormalities have no specific treatment, severe clinical manifestations of several notable electrolytes occur with significant frequency in the setting of malignancy. The treatment of life-threatening electrolyte abnormalities is reviewed here. Promising future treatments directed at the underlying physiology are also introduced.

The diseases we cause: Iatrogenic illness in a department of internal medicine

BACKGROUND

The aim of this study was to estimate the incidence, main causes, and risk factors of iatrogenic disease occurring in a department of internal medicine.

METHODS

Over a 1-year period, physicians systematically filled out a 2-page questionnaire for all patients admitted to the ward. A database was created and the data were statistically analyzed. Patients undergoing immunosuppressive, chemo-, or radiation therapy were excluded. Missing data were completed by reviewing the patients' charts. The patients were then divided into two groups: those with and those without iatrogenic disease. The groups were compared using several parameters including gender, age, social features, days of hospitalization, associated illness, functional status, medical impression, prognosis, associated renal or liver function impairment, drugs taken daily, and outcome. In the group with iatrogenic disease, the type, severity, and predictability were also analyzed.

RESULTS

Of the 879 patients admitted to the ward, 445 completed questionnaires and were included in the study. A total of 102 patients (22.9%) developed 121 iatrogenic events. Forty-four patients (43.1%) were admitted for iatrogenic illness, 10 (9.8%) developed life-threatening events, and in 3 (6.8%) it was the cause of death. Fifty-eight patients (56.8%) registered 77 episodes of iatrogenic disease during their hospital stay, 20 (19.6%) developed life-threatening events, and 9 (11.7%) died, 4 (5.2%) of an iatrogenic cause (nosocomial infections). Significant differences were found in 20 out of 26 parameters studied (p<0.005 for all cases; 95% confidence interval). Eighteen percent of all iatrogenic disease was severe, 61.9% predictable, 54.5% avoidable, and 59% drug-related, 80% of which was due to side effects or adverse reactions. Infection and metabolic and electrolyte disorders were the most frequent effects.

CONCLUSIONS

It is possible to identify risk factors for iatrogenic events. Chronically ill elderly inpatients are the main target of iatrogenic events.

Assessment of the efficacy and safety of intravenous conivaptan in euvolemic and hypervolemic hyponatremia

BACKGROUND

Most cases of hyponatremia--serum sodium concentration ([Na+]) < 135 mEq/l (< 135 mM)--are associated with an elevated plasma arginine vasopressin level. This study investigated the efficacy and tolerability of intravenous conivaptan (YM087), a vasopressin V1A/V2-receptor antagonist, in treating euvolemic and hypervolemic hyponatremia.

METHODS

Eighty-four hospitalized patients with euvolemic or hypervolemic hyponatremia (serum [Na+] 115 to < 130 mEq/l) were randomly assigned to receive intravenous placebo or conivaptan administered as a 30-min, 20-mg loading dose followed by a 96-hour infusion of either 40 or 80 mg/day. The primary efficacy measure was change in serum [Na+], measured by the baseline-adjusted area under the [Na+]-time curve. The secondary measures included time from first dose to a confirmed > or = 4 mEq/l serum [Na+] increase, total time patients had serum [Na+] > or = 4 mEq/l higher than baseline, change in serum [Na+] from baseline to the end of treatment, and number of patients with a confirmed > or = 6 mEq/l increase in serum [Na+] or normal [Na+] (> or = 135 mEq/l).

RESULTS

Both conivaptan doses increased area under the [Na+]-time curve during the 4-day treatment (p < 0.0001 vs. placebo). From baseline to the end of treatment, the least-squares mean +/- standard error serum [Na+] increase associated with placebo was 0.8 +/- 0.8 mEq/l; with conivaptan 40 mg/day, 6.3 +/- 0.7 mEq/l; and with conivaptan 80 mg/day, 9.4 +/- 0.8 mEq/l. Conivaptan significantly improved all secondary efficacy measures (p < 0.001 vs. placebo, both doses). Conivaptan was generally well tolerated, although infusion-site reactions led to the withdrawal of 1 (3%) and 4 (15%) of patients given conivaptan 40 and 80 mg/day, respectively.

CONCLUSION

Among patients with euvolemic or hypervolemic hyponatremia, 4-day intravenous infusion of conivaptan 40 mg/day significantly increased serum [Na+] and was well tolerated.

Validation of a clinical prognostic model to identify low-risk patients with pulmonary embolism

OBJECTIVE

To validate the Pulmonary Embolism Severity Index (PESI), a clinical prognostic model which identifies low-risk patients with pulmonary embolism (PE).

DESIGN

Validation study using prospectively collected data.

SETTING

A total of 119 European hospitals.

SUBJECTS

A total of 899 patients diagnosed with PE.

INTERVENTION

The PESI uses 11 clinical factors to stratify patients with PE into five classes (I-V) of increasing risk of mortality. We calculated the PESI risk class for each patient and the proportion of patients classified as low-risk (classes I and II). The outcomes were overall and PE-specific mortality for low-risk patients at 3 months after presentation. We calculated the sensitivity, specificity and predictive values to predict overall and PE-specific mortality and the discriminatory power using the area under the receiver operating characteristic curve.

RESULTS

Overall and PE-specific mortality was 6.5% (58/899) and 2.3% (21/899) respectively. Forty-seven per cent of patients (426/899) were classified as low-risk. Low-risk patients had an overall mortality of only 1.2% (5/426) and a PE-specific mortality of 0.7% (3/426). The sensitivity was 91 [95% confidence interval (CI): 81-97%] and the negative predictive value was 99% (95% CI: 97-100%) for overall mortality. The sensitivity was 86% (95% CI: 64-97%) and the negative predictive value was 99% (95% CI: 98-100%) for PE-specific mortality. The areas under the receiver operating characteristic curve for overall and PE-specific mortality were 0.80 (95% CI: 0.75-0.86) and 0.77 (95% CI: 0.68-0.86) respectively.

CONCLUSIONS

This validation study confirms that the PESI reliably identifies low-risk patients with PE who are potential candidates for less costly outpatient treatment.

Hyponatremia: current treatment strategies and the role of vasopressin antagonists

OBJECTIVE

Hyponatremia is a complex electrolyte disorder that results mainly from dysregulation of arginine vasopressin (AVP) by osmotic and nonosmotic mechanisms. Several populations, including the elderly, are at risk for the development of hyponatremia, and awareness of such risk factors can lead to an overall improvement in patient care. AVP receptor antagonists are promising new therapeutic options whose safety and efficacy have been clinically established for some forms of hyponatremia.

DATA SOURCES

A search of MEDLINE (1967-March 2007) was conducted, using the search terms aquaporins, AVP, AVP receptor antagonists, conivaptan, hyponatremia, lixivaptan, and tolvaptan. Additionally, data were obtained from manufacturers' prescribing information.

STUDY SELECTION AND DATA EXTRACTION

All articles identified from the reference search and data sources were evaluated. Material was included in this review if it was relevant to the pathophysiology and management of euvolemic and hypervolemic hyponatremia in hospitalized patients.

DATA SYNTHESIS

A large percentage of hospitalized patients are found to have symptomatic or asymptomatic hyponatremia. One study reported that 24.5% of intensive care patients admitted over a 3 month period experienced hyponatremia at some time during their hospitalization. Conventional management techniques include water restriction, demeclocycline, lithium, and urea, which have demonstrated variable efficacy and toxicity. AVP receptor antagonists, whose safety and efficacy have been established in clinical trials, are providing new therapeutic options.

CONCLUSIONS

AVP receptor antagonists appear to be safe and effective for the treatment of patients with hyponatremia. With conivaptan recently approved by the Food and Drug Administration for use in treating euvolemic and hypervolemic hyponatremia in hospitalized patients and lixivaptan and tolvaptan in the late stages of development, prudent use of these agents requires a thorough understanding of the clinical manifestations of hyponatremia to optimize therapeutic outcomes.

Prévalence et description des hyponatrémies dans les services de médecine interne de l'ouest de la France. Une enquête descriptive multicentrique type « jour donné »

PURPOSE

Few data are available on the prevalence and causes of hyponatremia in medical setting and to our knowledge, no recent descriptive study has been performed about hyponatremias in the French Departments of internal medicine.

METHOD

A "one day" descriptive multicentric study was performed in the medicine departments of the France West area. A questionnaire was mailed to physicians who had to take part in a annual regional meeting about "hyponatremias", one month later. Hyponatremia was defined by a blood sodium level under the normal value of the local laboratory. Each internist had to precise for all hyponatremias in course at the study day, the exact value, the discovery circumstances, the mechanisms and etiologies, the associated diseases, the course and treatments.

RESULTS

Seventy-four hyponatremias were identified. The overall prevalence was 12,1%. The prevalence of severe hyponatremias (under 120 mmol/l) was 1,1%. These latter represented 9,4% of the whole hyponatremias (7/74). Associated symptoms and diseases, the mechanisms, the suspected etiologies, the course and treatments are described in detail.

CONCLUSION

This multicentric study reports for the first time the prevalence, the clinical and etiological characteristics of hyponatremias coming from Internal Medecine Departments of the West area from France. The overall prevalence is lower in comparison with values usually reported in hospitalized patients, but the frequency of severe and moderate hyponatremias, the mechanisms and the suspected etiologies are identical to those reported in others countries.

Hyponatremia, arginine vasopressin dysregulation, and vasopressin receptor antagonism

Hyponatremia is often associated with arginine vasopressin (AVP) dysregulation that is regulated by the hypothalamo-neurohypophyseal tract in response to changes in plasma osmolality, commonly in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Potentially lethal complications of hyponatremia most frequently involve the central nervous system and include anorexia, fatigue, lethargy, delirium, seizures, hypothermia and coma, and require prompt treatment. Chronic hyponatremia also complicates patient care and is associated with increased morbidity and mortality, particularly among patients with congestive heart failure. Conventional treatments for hyponatremia (e.g. fluid restriction, diuretic treatment, and sodium replacement) may not be effective in all patients and can lead to significant adverse events. Preclinical and clinical trial results have shown that AVP receptor antagonism is a promising approach to the treatment of hyponatremia that directly addresses the effects of increased AVP and consequent decreased aquaresis, the electrolyte-sparing excretion of free water. Agents that antagonize V(2) receptors promote aquaresis and can lead to increased serum sodium. Dual-receptor antagonism, in which both V(2) and V(1A) receptors are blocked, may provide additional benefits in patients with hyponatremia.

Incidence and prevalence of hyponatremia

Hyponatremia is the most common electrolyte abnormality encountered in clinical practice. The reported frequency of the disorder is determined by a number of factors, including the definition of hyponatremia, the frequency of testing, the healthcare setting, and the patient population. This review focuses on the incidence and prevalence of hyponatremia. In acute hospital care, particular attention is given to admission versus hospital-acquired hyponatremia. Although less well studied, the epidemiology of hyponatremia in the ambulatory-based setting and the geriatric/nursing home population is also summarized. Finally, the frequency of hyponatremia occurring in special clinical conditions--including congestive heart failure, cirrhosis, pneumonia, and acquired immunodeficiency syndrome--as well as in marathon runners will be reviewed. Substantial additional work is still required to determine the true occurrence of hyponatremia in the various clinical settings. Beyond the phenomenologic value, advances in the epidemiology of hyponatremia should also provide insights in the prognostic implications as well as the preventive and management strategies of the disorder in various clinical settings.

Vasopressin excess and hyponatremia

Hyponatremia is a common electrolyte disorder that frequently is overlooked and undertreated. Although the pathophysiological process of hyponatremia is complex, arginine vasopressin (AVP) is a common etiologic factor. Excess AVP release by osmotic or nonosmotic stimuli or both can lead to sodium and water imbalance. Conventional treatment options for hyponatremia, including water restriction and administration of sodium chloride with or without loop diuretics, do not directly address the underlying water retention induced by excess AVP in many cases. Clinical trials showed that AVP-receptor antagonists, including lixivaptan, tolvaptan, and conivaptan, produce aquaresis, the electrolyte-sparing excretion of free water, to correct serum sodium concentration. We review results from recent clinical trials involving AVP-receptor antagonists in the treatment of hyponatremia associated with AVP excess.