The management of acute and chronic hyponatraemia

Addressing Inpatient Hyponatremia Through Targeted Automatic E-consults: A Pilot Randomized Trial

BACKGROUND

Hyponatremia is the most common electrolyte abnormality in hospitalized patients. Treatment of hyponatremia is associated with improved outcomes, but more than one in three cases of new onset hyponatremia is not corrected by the time of hospital discharge. Nephrologist input may improve the diagnosis and treatment of hyponatremia, but specialist resources are limited. Targeted automatic electronic consultations (TACos) may be one approach to provide expert nephrologist guidance to the workup and management of hyponatremia using a scalable model.

OBJECTIVE

Evaluate the feasibility and acceptability of a TACo intervention for hospitalized patients with hyponatremia.

DESIGN

Single-site, parallel-group cluster randomized trial.

PARTICIPANTS

Adult inpatients with hyponatremia on the hospital medicine service.

INTERVENTIONS

A nephrologist conducted TACos on intervention patients, making diagnostic and therapeutic recommendations daily (if warranted) until discharge or resolution of hyponatremia.

MAIN MEASURES

Measures of feasibility included the number of eligible participants, percentage receiving TACos, number of TACos per participant, and percentage of formal nephrology consults. Acceptability was assessed by a post-intervention survey. Clinical outcomes, including the percentage of hyponatremia cases that resolved by discharge, were also assessed.

KEY RESULTS

We identified 62 patients who met inclusion criteria: 38 in the intervention group and 24 in the control group. A nephrologist determined that 26 of 38 intervention patients (68%) would likely benefit from diagnostic and management recommendations; 67 TACos were performed (mean 2.6 per patient). Fourteen of 18 primary team physicians (78%) reported that the e-consults changed their management, and 15 of 18 (83%) wanted TACOs to continue. Resolution of hyponatremia, length of stay, 30-day readmissions, and costs were similar in the intervention and control groups.

CONCLUSIONS

Inpatient TACos for hyponatremia were feasible and acceptable to primary teams, and frequently led to changes in diagnosis and management. Further studies are needed to determine the impact of the TACo model on clinical outcomes and cost-effectiveness.

Hyponatremia in Guillain-Barre Syndrome: A Review of Its Pathophysiology and Management

Guillain-Barre syndrome (GBS) is the commonest cause of acute polyradiculoneuropathy that requires hospitalization. Many of these patients experience systemic and disease-related complications during its course. Notable among them is hyponatremia. Though recognized for decades, the precise incidence, prevalence, and mechanism of hyponatremia in GBS are not well known. Hyponatremia in GBS patients is associated with more severe in-hospital disease course, prolonged hospitalization, higher mortality, increased costs, and a greater number of other complications in the hospital and worse functional status at 6 months and at 1 year. Though there are several reports of low sodium associated with GBS, many have not included the exact temporal relationship of sodium or its serial values during GBS thereby underestimating the exact incidence, prevalence, and magnitude of the problem. Early detection, close monitoring, and better understanding of the pathophysiology of hyponatremia have therapeutic implications. We review the complexities of the relationship between hyponatremia and GBS with regard to its pathophysiology and treatment.

Classifying Hypotonic Hyponatremia by Projected Treatment Effects - A Quantitative 3-Dimensional Framework

Introduction

The diagnostic algorithms currently used for hypotonic hyponatremia focus primarily on impaired urinary dilution and often neglect the influence of free water intake and solute excretion. We hypothesized that, in each case of hypotonic hyponatremia different pathophysiological mechanisms play a role simultaneously.

Methods

Using clinical data of the previous observational Co-Med study, we defined each case of hypotonic hyponatremia concurrently in 3 dimensions as follows: (i) high net free water intake (HNFWI), (ii) impaired dilution of the urine (IDU), and (iii) low nonelectrolyte solute excretion (LNESE). For each dimension, a "standard delta sodium" (sdna) was calculated reflecting the expected difference to the serum sodium concentration, that would result from changing a dimension to a specific and equivalent target level.

Results

Results from 279 patients were used for this analysis. With target levels of free water intake and urine osmolality at the fifth percentile, and nonelectrolyte solute excretion at the 95th percentile, median (interquartile range) sdna values were 7.1 (4.8-10.2) for HNFWI, 11.8 (7.0-18.6) for IDU and 2.6 (1.6-4.2) mmol/l per 24 hours for LNESE. Sdna results in individual patients were highest with IDU in 68.5%, HNFWI in 30.8% and 0.7% with LNESE. At an sdna-level of at least 4mmol/l per 24 hours, the prevalence of HNFWI was 78.9%, IDU 87.1%, and LNESE 26.5%. 77.5% of patients had 2 or all 3 mechanisms present. Hyponatremia was mostly multifactorial in subgroups according to classic categories of hyponatremia and typical comorbidities as well.

Conclusion

Hypotonic hyponatremia can be quantitatively defined by 3 dimensions. Most cases should be considered multifactorial.

Effect of protein supplementation on plasma sodium levels in the syndrome of inappropriate antidiuresis: a monocentric, open-label, proof-of-concept study-the TREASURE study

IMPORTANCE

The syndrome of inappropriate antidiuresis (SIAD) can be treated with oral urea; however, compliance is impaired by its poor palatability.

OBJECTIVE

To investigate whether dietary proteins could increase plasma sodium levels through urea-induced osmotic diuresis.

DESIGN

An open-label, proof-of-concept trial.

SETTING

University Hospital of Basel, Switzerland, between October 2021 and February 2023.

PARTICIPANTS

Outpatients with chronic SIAD.

INTERVENTIONS OR EXPOSURES

Ninety grams of protein daily for 7 days in the form of protein powder, followed by 30 g of oral urea daily for 7 days after a wash-out period of ≥1 week.

MAIN OUTCOMES AND MEASURES

The increase in sodium levels from baseline to the end of the 7-day protein supplementation.

RESULTS

Seventeen patients were included. After 7 days of 90 g daily protein supplementation (n = 17), plasma sodium levels increased from 131 (129-133) to 133 (132-137), that is, by a median of 3 mmol L-1 (0-5) (P = .01). Plasma urea levels increased by 3 mmol L-1 (1.7-4.9) (P < .01), and urine urea to creatinine ratio increased by 21.2 mmol mmol-1 (6.2-29.1) (P < .01). After 7 days of 30 g oral urea (n = 10), plasma sodium levels increased from 132 (130-133) to 134 (131-136), that is, by a median of 2 mmol L-1 (1-3) (P = .06). Plasma urea levels increased by 5.8 mmol L-1 (2.7-9.2) (P < .01), and urine urea to creatinine ratio increased by 31.0 mmol mmol-1 (18.7-45.1) (P < .01).

CONCLUSIONS AND RELEVANCE

Our findings suggest that protein powder increases plasma sodium levels in patients with chronic SIAD through protein-induced ureagenesis and osmotic diuresis. The effects are comparable with oral urea.

Incidence trends and risk factors for hyponatremia in epilepsy patients: A large-scale real-world data study

OBJECTIVE

This study aimed to evaluate the annual incidence and risk factors of hyponatremia in pediatric, adult, and older adult patients with epilepsy.

METHODS

We enrolled 26,179 patients: 8598 pediatric patients (aged 0-15 years), 16,476 adults (aged 16-64 years), and 1105 older adults (aged ≥65 years). Patients were included if their serum sodium levels were measured between January 2006 and December 2020. Moderate-severe hyponatremia was defined as a serum sodium level of less than 130 mEq/L.

RESULTS

From 2006 to 2020, 677 patients (2.6%) developed moderate-severe hyponatremia. The incidence of hyponatremia per 1000 person-years was 3.1 in the pediatric group, 19.8 in the adult group, and 50.4 in the older adult group. The incidence increased markedly from 36.8 in 2007 to 58.5 in 2020 in the older adult group but remained unchanged in the adult group and tended to decrease in the pediatric group. In the multiple logistic regression model, use of carbamazepine, valproate, phenytoin, phenobarbital, benzodiazepines, and antipsychotics was found to be a significant risk factor for hyponatremia. In adult patients, carbamazepine, benzodiazepine, and antipsychotics induced hyponatremia in a dose-dependent manner. Concomitant use of zonisamide reduced the risk of hyponatremia.

SIGNIFICANCE

Hyponatremia will become an increasingly important concern in clinical settings because the population of epilepsy patients is aging. Serum sodium levels should be monitored carefully when patients are receiving first-generation antiseizure medications or antipsychotics or combinations of these drugs. Our findings may help to minimize the risk of hyponatremia in epilepsy patients.

The role of tolvaptan in pulmonary hypertension: A retrospective study

Pulmonary hypertension (PH) is a severe form of pulmonary vascular disease that can lead to right heart failure (RHF). Nearly 2-thirds of patients with PH die within 5 years. Studies suggest that a new diuretic medication, called tolvaptan (TLV), can be used to treat PH. However, there is still insufficient evidence to confirm its effectiveness. Therefore, we investigated the role of TLV in patients with PH. This retrospective study included 73 patients with PH hospitalized in Shanghai Pulmonary Hospital between November 2019 and March 2022. All patients received 7.5 to 15.0 mg of TLV for 3 to 21 days starting at admission, in addition to targeted drugs and traditional diuretic therapy. The outcomes included the blood pressure, urine and water intake volumes, electrolyte concentrations, and renal, liver, and cardiac function indexes before and after TLV treatment. In addition, we assessed the clinical symptoms and adverse reactions during the treatment. After TLV treatment, the water intake and urine volumes significantly increased, and body weight, diastolic blood pressure (DBP) and mean arterial pressure significantly decreased. Total bilirubin, direct bilirubin, N-terminal pro-brain natriuretic peptide, and serum uric acid (UA) levels after TLV treatment were significantly lower than before treatment. After TLV treatment, dyspnea significantly improved in 71 of 73 patients, and lower limb edema disappeared in 42 of 53 patients. No obvious adverse reactions occurred during the TLV treatment period. These results suggest that adding TLV to targeted drug and traditional diuretic therapies is effective for patients with PH. However, more data are required to support these findings.