Management of Hyponatremia in Heart Failure: Practical Considerations

Case report: Acute severe hyponatremia-induced seizures in a newborn: a community-acquired case and literature review

Severe neonatal hyponatremia represents a critical electrolyte imbalance with potentially severe neurological outcomes, a condition rarely documented in community-acquired, full-term newborns. This report underscores a unique case of a 23-day-old, previously healthy, full-term male neonate experiencing severe hyponatremia that precipitated seizures, underscoring the urgency of prompt recognition and intervention. The neonate presented with symptoms including vomiting, groaning, chills, fixed staring, and limb tremors. Critical findings upon admission encompassed hypothermia, hypotension, tachycardia, and tachypnea accompanied by significant weight loss. The clinical presentation was marked by dehydration, lethargy, weak crying, a fixed gaze, irregular breathing, and coarse lung sounds, yet a distended abdomen, hypertonic limb movements, and recurrent seizures were observed. Immediate interventions included establishing IV access, rewarming, mechanical ventilation, seizure management, volume expansion, dopamine for circulatory support, and initiation of empirical antibiotics. Diagnostic evaluations revealed a sodium ion concentration of 105.9 mmol/L, while amplitude-integrated electroencephalography (aEEG) detected pronounced seizure activity characterized by a lack of sleep-wake rhythmicity, noticeable elevation in both the lower and upper amplitude margins, and a sustained decrease in the lower margin voltage dropping below 5 μV, presenting as sharp or serrated waveforms. The management strategy entailed rapid electrolyte normalization using hypertonic saline and sodium bicarbonate, anticonvulsant therapy, and comprehensive supportive care, with continuous aEEG monitoring until the cessation of seizures. Remarkably, by the third day, the neonate's condition had stabilized, allowing for discharge in good health 10 days post-admission. At a 16-month follow-up, the child exhibited no adverse neurological outcomes and demonstrated favorable growth and development. Our extensive review on the etiology, clinical manifestations, aEEG monitoring, characteristics of seizures induced by severe neonatal hyponatremia, treatment approaches, and the prognosis for seizures triggered by severe hyponatremia aims to deepen the understanding and enhance clinical management of this complex condition. It stresses the importance of early detection, accurate diagnosis, and customized treatment protocols to improve outcomes for affected neonates. Additionally, this review accentuates the indispensable role of aEEG monitoring in managing neonates at elevated risk for seizures. Yet, the safety and efficacy of swiftly administering hypertonic saline for correcting severe hyponatremia-induced seizures necessitate further investigation through medical research.

Role of Vasoactive Hormone-Induced Signal Transduction in Cardiac Hypertrophy and Heart Failure

Heart failure is the common concluding pathway for a majority of cardiovascular diseases and is associated with cardiac dysfunction. Since heart failure is invariably preceded by adaptive or maladaptive cardiac hypertrophy, several biochemical mechanisms have been proposed to explain the development of cardiac hypertrophy and progression to heart failure. One of these includes the activation of different neuroendocrine systems for elevating the circulating levels of different vasoactive hormones such as catecholamines, angiotensin II, vasopressin, serotonin and endothelins. All these hormones are released in the circulation and stimulate different signal transduction systems by acting on their respective receptors on the cell membrane to promote protein synthesis in cardiomyocytes and induce cardiac hypertrophy. The elevated levels of these vasoactive hormones induce hemodynamic overload, increase ventricular wall tension, increase protein synthesis and the occurrence of cardiac remodeling. In addition, there occurs an increase in proinflammatory cytokines and collagen synthesis for the induction of myocardial fibrosis and the transition of adaptive to maladaptive hypertrophy. The prolonged exposure of the hypertrophied heart to these vasoactive hormones has been reported to result in the oxidation of catecholamines and serotonin via monoamine oxidase as well as the activation of NADPH oxidase via angiotensin II and endothelins to promote oxidative stress. The development of oxidative stress produces subcellular defects, Ca2+-handling abnormalities, mitochondrial Ca2+-overload and cardiac dysfunction by activating different proteases and depressing cardiac gene expression, in addition to destabilizing the extracellular matrix upon activating some metalloproteinases. These observations support the view that elevated levels of various vasoactive hormones, by producing hemodynamic overload and activating their respective receptor-mediated signal transduction mechanisms, induce cardiac hypertrophy. Furthermore, the occurrence of oxidative stress due to the prolonged exposure of the hypertrophied heart to these hormones plays a critical role in the progression of heart failure.

[Effectiveness of urea administration for the treatment of hyponatremia in heart failure]

OBJECTIVES

To assess the efficacy and safety of urea in patients with hyponatremia and heart failure (HF).

METHODS AND RESULTS

This is a retrospective observational analytical study of patients with HF and hyponatremia (Na+ <135mmol/L). Forty-nine patients treated with urea and 47 patients who did not receive urea, all under standard treatment (according to usual clinical practice) for HF, were included and followed up at Álvaro Cunqueiro Hospital in Vigo (Spain) between January 2013 and May 2022. The study evaluated the normalization of sodium levels (Na >135mmol/L). The initial natremia at the start of oral urea treatment was 127±5.22 mmol/L, at 24h the sodium level was 128±2.47 (P<.009), and the mean on the day of normalization was 135.19±4.23mmol/L (P<.005). The average number of days to achieve sodium normalization was 5.03±2.37 days. The initial uremia at the start of urea treatment was 73±46.93mg/dL, and the mean on the day of Na+ normalization was 116.05±63.64mg/dL (P<.002). The average oral urea dose was 22.5g/day. No relevant adverse effects were observed, nor were there significant changes in creatinine levels.

CONCLUSIONS

Oral urea treatment, when added to standard treatment for short periods of time, is safe and effective in correcting natremia in patients with hypervolemic HF with hyponatremia.

Association between hyponatremia and adverse clinical outcomes of heart failure: current evidence based on a systematic review and meta-analysis

Background

Heart failure (HF) is a global health challenge. The perturbations in fluid and electrolyte equilibrium, particularly the compromised sodium balance associated with HF lead to high mortality rates. Hence, elucidating the correlation between serum sodium levels and the prognosis of HF is of paramount importance. This study aimed to conduct a comprehensive meta-analysis to thoroughly investigate the interplay between hyponatremia and the prognostic outlook of individuals with HF.

Methods

A comprehensive search of bibliographic databases including PubMed, Embase, and the Cochrane Central Register of Controlled Trials was conducted to identify relevant observational studies examining the association between hyponatremia and prognosis of HF. Data extraction, synthesis, and assessment of risk of bias were conducted. Meta-analytic methods, sensitivity analyses, and heterogeneity test were employed as appropriate to synthesize the data.

Results

A total of 43,316 patients with HF were included spanning 25 selected studies. The pooled data revealed a notable association between hyponatremia and elevated risks across short and long-term mortality of HF. Specifically, hyponatremia was found to significantly increase the likelihood of all-cause mortality (Hazard ratio [HR] = 1.94, 95% confidence interval [CI]: 1.78-2.12); 1-year mortality (HR = 1.67, 95%CI: 1.46-1.90); 30-day mortality (HR = 2.03, 95%CI: 1.73-2.25); cardiac mortality (HR = 2.11, 95%CI: 1.81-2.46); and in-hospital mortality (HR = 1.64, 95%CI: 1.15-2.34).

Conclusion

Our meta-analysis emphasizes the significant impact of hyponatremia on mortality in the HF patient population, highlighting the critical importance of maintaining stable serum sodium levels in HF management.

Tolvaptan for water retention in heart failure: a systematic review

OBJECTIVE

The purpose of this systematic review is to collect, appraise, and synthesize existing evidence from systematic reviews and meta-analyses (SRs/MAs) on the effectiveness of tolvaptan for water retention in heart failure.

METHODS

A comprehensive literature search was performed on PubMed, EMBASE, web of science, Cochrane reviews for SRs/Mas published between the databases' establishment to November 17, 2021. All the records were managed with Endnote 20. Standardized forms were used to extract data. Revman 5.3 was used to make forest plots to show the characteristics of outcomes. The methodological and evidence quality were respectively evaluated by AMSTAR-2 (A MeaSurement Tool to Assess systematic Reviews 2) and GRADE (Grading of Recommendation of Assessment, Development, and Evaluation) system.

RESULTS

A total of 9 SRs/Mas between 2015 to 2020 met inclusion criteria. Serum sodium concentration and urine output were considered as primary outcomes and body weight change and all-cause mortality as second outcomes. Through conducting forest plots, it appeared that tolvaptan brought more positive effect than conventional therapies. It was pessimistic when it comes to the quality of the 9 studies. all the 9 articles were rated as low-quality because AMSTAR 2 evaluation showed that they each had at least one critical item (items 2, 4, 7, 9, 11, 13 and 15) defect. Besides, every article had a few non-critical item defects too. The result of GRADE assessment was not optimistic, so the overall quality of the evidences was low as well.

CONCLUSION

Tolvaptan can be recommended for water retention in HF patients, but more evidence is needed.