Osmotic demyelination syndrome and thoughts on its prevention

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

Background

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

Methods

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

Results

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

Conclusions

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

Safety and efficacy of proactive versus reactive administration of desmopressin in severe symptomatic hyponatremia: a randomized controlled trial

This randomized controlled trial aimed to evaluate the safety and efficacy of proactive versus reactive desmopressin (DDAVP) strategies in treating severe symptomatic hyponatremia. Conducted from June 20, 2022, to February 20, 2023, it involved 49 patients with serum sodium levels below 125 mmol/L. Patients were assigned to either the proactive group, receiving DDAVP immediately upon diagnosis, or the reactive group, receiving DDAVP only if the serum sodium level tended to be overcorrected. The primary outcome was the incidence of overcorrection. The study revealed no significant difference in the overcorrection incidence between the proactive (16.7%) and reactive (28%) groups (p = 0.54). The change in serum sodium levels at 1, 6, 12, and 24 h were not different, however, at 48 h, the proactive group exhibited a higher but still safe change in serum sodium levels compared to the reactive group (10.3 ± 3.6 mmol/L vs. 7.7 ± 3.6 mmol/L, p = 0.013). Other parameters including time to symptom improvement, total intravenous fluid administered, DDAVP dose, urine volume, hospital stay duration, osmotic demyelination syndrome incidence, and 28-day mortality did not significantly differ between the groups. In conclusion, our findings suggest that there was no significant disparity in overcorrection rates between proactive and reactive DDAVP strategies for treating severe symptomatic hyponatremia. However, further large-scale studies are warranted to validate these results.

Predictive correction of serum sodium concentration with formulas derived from the Edelman equation in patients with severe hyponatremia

Severe hyponatremia can cause life-threatening cerebral edema. Treatment comprises rapid elevation of serum sodium concentration; however, overcorrection can result in osmotic demyelination. This study investigated potential factors, including predictive correction based on the Edelman equation, associated with appropriate correction in 221 patients with a serum sodium concentration ≤ 120 mEq/L who were admitted to a hospital in Nagoya, Japan. Appropriate correction was defined as an elevation in serum sodium concentration in the range of 4-10 mEq/L in the first 24 h and within 18 mEq/L in the first 48 h after the start of the correction. Appropriate corrections were made in 132 (59.7%) of the 221 patients. Multivariate analysis revealed that predictive correction with an infusate and fluid loss formula derived from the Edelman equation was associated with appropriate correction of serum sodium concentration (adjusted odds ratio, 7.84; 95% confidence interval, 2.97-20.64). Relative without its use, the predictive equation results in a lower proportion of undercorrection (14.3% vs. 48.0%, respectively) and overcorrection (1.0% vs. 12.2%, respectively). These results suggest that predictive correction of serum sodium concentrations using the formula derived from the Edelman equation can play an essential role in the appropriate management of patients with severe hyponatremia.

Hyponatremia in the emergency department

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