The Corrected Serum Sodium Concentration in Hyperglycemic Crises: Computation and Clinical Applications

Quantifying the Deficits of Body Water and Monovalent Cations in Hyperglycemic Emergencies

Background/Objectives: Hyperglycemic emergencies cause significant losses of body water, sodium, and potassium. This report presents a method for computing the actual losses of water and monovalent cations in these emergencies. Methods: We developed formulas for computing the losses of water and monovalent cations as a function of the presenting serum sodium and glucose levels, the sum of the concentrations of sodium plus potassium in the lost fluids, and body water at the time of hyperglycemia presentation as measured by bioimpedance or in the initial euglycemic state as estimated by anthropometric formulas. The formulas for computing the losses from hyperglycemia were tested in examples of hyperglycemic episodes. Results: The formulas were tested in two patient groups, those with or without known weight loss during the development of hyperglycemia. In the first group, these formulas were applied to estimate the losses of body water and monovalent cations in (a) a previously published case of a boy with diabetic ketoacidosis and known weight loss who, during treatment not addressing his water deficit, developed severe hypernatremia and (b) a comparison of water loss computed by this new method with the reported average fluid gained during treatment of the hyperglycemic hyperosmolar state in a published study. In the second group, the formulas were applied in hypothetical subjects with varying levels of initial body water, serum sodium, and glucose at the time of hyperglycemia and sums of sodium and potassium concentrations in the lost fluids. Conclusions: Losses of body water and monovalent cations, which determine the severity of dehydration and hypovolemia, vary significantly between patients with hyperglycemic emergencies presenting with the same serum glucose and sodium concentrations. These losses can be calculated using estimated or measured body water values. Prospective studies are needed to test this proof-of-concept report.

Diagnostic and Therapeutic Strategies to Severe Hyponatremia in the Intensive Care Unit

Hyponatremia is the most common electrolyte abnormality encountered in critically ill patients and is linked to heightened morbidity, mortality, and healthcare resource utilization. However, its causal role in these poor outcomes and the impact of treatment remain unclear. Plasma sodium is the main determinant of plasma tonicity; consequently, hyponatremia commonly indicates hypotonicity but can also occur in conjunction with isotonicity and hypertonicity. Plasma sodium is a function of total body exchangeable sodium and potassium and total body water. Hypotonic hyponatremia arises when total body water is proportionally greater than the sum of total body exchangeable cations, that is, electrolyte-free water excess; the latter is the result of increased intake or decreased (kidney) excretion. Hypotonic hyponatremia leads to water movement into brain cells resulting in cerebral edema. Brain cells adapt by eliminating solutes, a process that is largely completed by 48 h. Clinical manifestations of hyponatremia depend on its biochemical severity and duration. Symptoms of hyponatremia are more pronounced with acute hyponatremia where brain adaptation is incomplete while they are less prominent in chronic hyponatremia. The authors recommend a physiological approach to determine if hyponatremia is hypotonic, if it is mediated by arginine vasopressin, and if arginine vasopressin secretion is physiologically appropriate. The treatment of hyponatremia depends on the presence and severity of symptoms. Brain herniation is a concern when severe symptoms are present, and current guidelines recommend immediate treatment with hypertonic saline. In the absence of significant symptoms, the concern is neurologic sequelae resulting from rapid correction of hyponatremia which is usually the result of a large water diuresis. Some studies have found desmopressin useful to effectively curtail the water diuresis responsible for rapid correction.

Sodium and Hematocrit Levels' Correlation and Clinical Impacts in Jordanian Hemodialysis Patients

AIM

Given cofounders, this retrospective study investigates the correlation between hyponatremia status and hematocrit (Hct) changes, as well as the clinical utility of these two prognosticators in relation to overall health status.

METHODS

The study was retrospectively conducted on adult hemodialysis (HD) patients at the King Hussein Medical Center in Amman, Jordan, from 2015 to 2022. It looked at how sodium (Na) levels, the hematocrit-to-hemoglobin ratio (HHR), and outcomes of interest were related. The study examined acute myocardial infarction, stroke, refractory hypertension, dialysis graft thrombosis, and all-cause mortality as the composite outcomes of interest (cOI). We conducted a series of receiver operating characteristics, binary logistic regression (BLgR), and sensitivity analyses between each tested prognosticator and the cOI. We constructed and illustrated a multiple logistic regression (MLgR) model to investigate the adjusted association of each prognosticator against the tested composite outcome probability.

RESULTS

The majority of HD patients were hemolyzed for a period of four to seven years. The constructed binary regression modeling for each prognosticator was [e (109.36 - 0.849 × Na)/[1 + e (109.36 - 0.849 × Na)] and [e (16.033 - 6.388 × HHR)/[1 + e (16.033 - 6.388 ×HHR)], with a 35.57% probability of cOI at the optimal Na of 129.51 mEq/l and a 42.8% at optimal HHR of 2.555:1. When the length of hemodialysis (LOD) was introduced into the MLgR modeling all the investigated independent variables were significant except the HHR (p-value = 0.908).

CONCLUSION

A higher LOD, lower Na, and lower HHR all support a positive cOI probability status. Regular inspection of Na and HHR and ensuring their closet to their optimal thresholds are mandatory to mitigate the risk of higher cOI probability.

Diazoxide-related Hyperglycemic Hyperosmolar State in a Child With Kabuki Syndrome

Diazoxide is a commonly used first-line medication for the treatment of hyperinsulinism. Hyperglycemia may occur with diazoxide use. However, hyperglycemic hyperosmolar state (HHS) secondary to diazoxide is an exceedingly rare but potentially life-threatening adverse effect. We present a case of a 2-year-old with Kabuki syndrome and hyperinsulinism on diazoxide. She presented with 4 days of fever, respiratory symptoms, and lethargy. She was influenza B positive. Initial workup indicated HHS, with an elevated serum glucose (47.1 mmol/L [847.8 mg/dL]; reference range 3.9-6.0 mmol/L; 70-108 mg/dL), serum osmolality (357 mmol/kg H2O; reference 282-300 mmol/kg H2O) but absent urine ketones and no metabolic acidosis (venous pH 7.34). Her course was complicated by an acute kidney injury. Management in the hospital included discontinuation of diazoxide and intravenous fluid resuscitation, following which hyperglycemia and hyperosmolarity resolved. No insulin therapy was required. She remained normoglycemic without diazoxide for 2 weeks but subsequently required restarting of diazoxide for hypoglycemia. This case highlights the need for early recognition and prompt management of diazoxide-related HHS to reduce negative outcomes. We present the first case report of a child with Kabuki syndrome and hyperinsulinism with diazoxide-induced HHS.

Hypernatremia in Hyperglycemia: Clinical Features and Relationship to Fractional Changes in Body Water and Monovalent Cations during Its Development

In hyperglycemia, the serum sodium concentration ([Na]S) receives influences from (a) the fluid exit from the intracellular compartment and thirst, which cause [Na]S decreases; (b) osmotic diuresis with sums of the urinary sodium plus potassium concentration lower than the baseline euglycemic [Na]S, which results in a [Na]S increase; and (c), in some cases, gains or losses of fluid, sodium, and potassium through the gastrointestinal tract, the respiratory tract, and the skin. Hyperglycemic patients with hypernatremia have large deficits of body water and usually hypovolemia and develop severe clinical manifestations and significant mortality. To assist with the correction of both the severe dehydration and the hypovolemia, we developed formulas computing the fractional losses of the body water and monovalent cations in hyperglycemia. The formulas estimate varying losses between patients with the same serum glucose concentration ([Glu]S) and [Na]S but with different sums of monovalent cation concentrations in the lost fluids. Among subjects with the same [Glu]S and [Na]S, those with higher monovalent cation concentrations in the fluids lost have higher fractional losses of body water. The sum of the monovalent cation concentrations in the lost fluids should be considered when computing the volume and composition of the fluid replacement for hyperglycemic syndromes.

Prevalence, Risk Factors, and Mortality of Patients Presenting with Moderate and Severe Hyponatremia in Emergency Departments

Background

Hyponatremia is among the most common electrolyte disturbances encountered in clinical practice and is associated with a high rate of morbidity and mortality. However, there are very limited data on adult cases presenting to emergency departments with hyponatremia.

Objectives

This study aimed to evaluate the frequency, clinical characteristics, and outcomes in hyponatremic patients presenting to emergency departments.

Methods

This retrospective study analyzed all patients older than 18 years who visited our institution's emergency department between October 2018 and October 2019 and has a serum sodium (Na) level <130 mmol/L.

Results

Among 24,982 patients who visited the emergency department and had a documented serum sodium level, 284 were included. Patients' median age was 67.13 ± 14.8 years. Younger patients are less likely to develop severe hyponatremia compared to older patients (adjusted odds ratio (AOR): 0.415; 95% confidence interval (CI): 0.231-0.743; p=0.003). Asymptomatic hyponatremia and gastrointestinal manifestations were the most common presenting hyponatremia symptoms (33.7% and 24.2%, respectively). Proton pump inhibitor (PPI) use, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACE/ARB) use, and spironolactone use (OR = 2.6 and 3.9, 2.3 with a p=0.02, 0.03, and 0.05, respectively) were associated with increased odds of severe hyponatremia. There is no difference in the overall mortality rate within 6 months of presentation between severe and moderate hyponatremia groups (11.1% versus 16.2%, p=0.163).

Conclusion

Moderate and severe hyponatremia are not uncommon among patients presenting to emergency departments. Moderate hyponatremia can be asymptomatic with clinical significance. Older patients, use of PPI, use of ACEi/ARBs, and spironolactone use were associated with an increased risk of severe hyponatremia compared to moderate. Further prospective analysis of a larger population is needed to confirm our findings.

Pseudohyponatremia: Mechanism, Diagnosis, Clinical Associations and Management

Pseudohyponatremia remains a problem for clinical laboratories. In this study, we analyzed the mechanisms, diagnosis, clinical consequences, and conditions associated with pseudohyponatremia, and future developments for its elimination. The two methods involved assess the serum sodium concentration ([Na]_S) using sodium ion-specific electrodes: (a) a direct ion-specific electrode (ISE), and (b) an indirect ISE. A direct ISE does not require dilution of a sample prior to its measurement, whereas an indirect ISE needs pre-measurement sample dilution. [Na]_S measurements using an indirect ISE are influenced by abnormal concentrations of serum proteins or lipids. Pseudohyponatremia occurs when the [Na]_S is measured with an indirect ISE and the serum solid content concentrations are elevated, resulting in reciprocal depressions in serum water and [Na]_S values. Pseudonormonatremia or pseudohypernatremia are encountered in hypoproteinemic patients who have a decreased plasma solids content. Three mechanisms are responsible for pseudohyponatremia: (a) a reduction in the [Na]_S due to lower serum water and sodium concentrations, the electrolyte exclusion effect; (b) an increase in the measured sample's water concentration post-dilution to a greater extent when compared to normal serum, lowering the [Na] in this sample; (c) when serum hyperviscosity reduces serum delivery to the device that apportions serum and diluent. Patients with pseudohyponatremia and a normal [Na]_S do not develop water movement across cell membranes and clinical manifestations of hypotonic hyponatremia. Pseudohyponatremia does not require treatment to address the [Na]_S, making any inadvertent correction treatment potentially detrimental.

Hyponatremia Demystified: Integrating Physiology to Shape Clinical Practice

Hyponatremia is one of the most common problems encountered in clinical practice and one of the least-understood because accurate diagnosis and management require some familiarity with water homeostasis physiology, making the topic seemingly complex. The prevalence of hyponatremia depends on the nature of the population studied and the criteria used to define it. Hyponatremia is associated with poor outcomes including increased mortality and morbidity. The pathogenesis of hypotonic hyponatremia involves the accumulation of electrolyte-free water caused by either increased intake and/or decrease in kidney excretion. Plasma osmolality, urine osmolality, and urine sodium can help to differentiate among the different etiologies. Brain adaptation to plasma hypotonicity consisting of solute extrusion to mitigate further water influx into brain cells best explains the clinical manifestations of hyponatremia. Acute hyponatremia has an onset within 48 hours, commonly resulting in severe symptoms, while chronic hyponatremia develops over 48 hours and usually is pauci-symptomatic. However, the latter increases the risk of osmotic demyelination syndrome if hyponatremia is corrected rapidly; therefore, extreme caution must be exercised when correcting plasma sodium. Management strategies depend on the presence of symptoms and the cause of hyponatremia and are discussed in this review.

Hyponatremia in peritoneal dialysis patients

Hyponatremia is the most common disorder of body fluid and electrolyte balance encountered in clinical practice, and also in peritoneal dialysis (PD) population. Depending on the severity and the speed of drop in sodium concentration, the symptoms can vary from asymptomatic hyponatremia to mild and non-specific symptoms or severe and life-threatening situations. Hyponatremia is associated with high morbidity and mortality. Its pathophysiology is complex, specifically in patients undergoing PD. The etiological workup can be cumbersome but is of paramount importance for early and appropriate treatment. In this article, we review the clinical manifestations as well as the pathophysiology and the specific etiologies of hyponatremia in peritoneal dialysis patients, and we propose a diagnostic algorithm.   

What Is the Optimal Speed of correction of the Hyperosmolar Hyperglycemic State in Diabetic Ketoacidosis? An Observational Cohort Study of U.S. Intensive Care Patients

OBJECTIVE

The international guidelines for the treatment of diabetic ketoacidosis (DKA) advise against rapid changes in osmolarity and glucose; however, the optimal rates of correction are unknown. We aimed to evaluate the rates of change in tonicity and glucose level in intensive care patients with DKA and their relationship with mortality and altered mental status.

METHODS

This is an observational cohort study using 2 publicly available databases of U.S. intensive care patients (Medical Information Mart for Intensive Care-IV and Electronic Intensive Care Unit), evaluating adults with DKA and associated hyperosmolarity (baseline Osm ≥300 mOsm/L). The primary outcome was hospital mortality. The secondary neurologic outcome used a composite of diagnosed cerebral edema or Glasgow Coma Scale score of ≤12. Multivariable regression models were used to control for confounding factors.

RESULTS

On adjusted analysis, patients who underwent the most rapid correction of up to approximately 3 mmol/L/hour in tonicity had reduced mortality (n = 2307; odds ratio [OR], 0.21; overall P < .001) and adverse neurologic outcomes (OR, 0.44; P < .001). Faster correction of glucose levels up to 5 mmol/L/hour (90 mg/dL/hour) was associated with improvements in mortality (n = 2361; OR, 0.24; P = .020) and adverse neurologic events (OR, 0.52; P = .046). The number of patients corrected significantly faster than these rates was low. A maximal hourly rate of correction between 2 and 5 mmol/L for tonicity was associated with the lowest mortality rate on adjusted analysis.

CONCLUSION

Based on large-volume observational data, relatively rapid correction of tonicity and glucose level was associated with lower mortality and more favorable neurologic outcomes. Avoiding a maximum hourly rate of correction of tonicity >5 mmol/L may be advisable.

Edelman Revisited: Concepts, Achievements, and Challenges

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

Dysnatremias in Chronic Kidney Disease: Pathophysiology, Manifestations, and Treatment

The decreased ability of the kidney to regulate water and monovalent cation excretion predisposes patients with chronic kidney disease (CKD) to dysnatremias. In this report, we describe the clinical associations and methods of management of dysnatremias in this patient population by reviewing publications on hyponatremia and hypernatremia in patients with CKD not on dialysis, and those on maintenance hemodialysis or peritoneal dialysis. The prevalence of both hyponatremia and hypernatremia has been reported to be higher in patients with CKD than in the general population. Certain features of the studies analyzed, such as variation in the cut-off values of serum sodium concentration ([Na]) that define hyponatremia or hypernatremia, create comparison difficulties. Dysnatremias in patients with CKD are associated with adverse clinical conditions and mortality. Currently, investigation and treatment of dysnatremias in patients with CKD should follow clinical judgment and the guidelines for the general population. Whether azotemia allows different rates of correction of [Na] in patients with hyponatremic CKD and the methodology and outcomes of treatment of dysnatremias by renal replacement methods require further investigation. In conclusion, dysnatremias occur frequently and are associated with various comorbidities and mortality in patients with CKD. Knowledge gaps in their treatment and prevention call for further studies.

Case Series: Management of Hypernatremia in DKA in a Tertiary Healthcare Setting in a Developing Country

Diabetic ketoacidosis (DKA) commonly presents with hyponatremia, but hypernatremia is a rare case. We report two cases of hypernatremia, a 54-year-old woman (case 1) admitted with altered sensorium with blood glucose unrecordably high, serum sodium 134 mmol/L and an 18-year-old girl (case 2) admitted with reduced levels of consciousness, a random blood sugar of 21.2 mmol/L and serum sodium of 121 mmol/L. Case 1 was hydrated with isotonic saline and serum sodium values then escalated to 154 mmol/L on day 2, reaching 166 mmol/L on day 4. Case 2 was hydrated with isotonic saline and also given hypertonic saline for treatment of hyponatremia, and the sodium levels for this patient rose to 153 mmol/L on day 2 reaching a maximum of 176 mmol/L on day 3. On day 2, both patients were switched to half strength Darrow’s for correction of the hypernatremia along with insulin therapy. The patients recovered fully and were discharged without any sequelae. These reports exhibit a learning point in the choice of intravenous fluids for the treatment of DKA. They also show the need to delay the correction of hyponatremia in patients with high blood glucose levels.