hyponatremia | definition

lower-than-normal levels of sodium in the blood


Betts, J. G., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D. H., … DeSaix, P. (n.d.). Anatomy and Physiology. Houston, Texas: OpenStax. Access for free at: https://openstax.org/details/books/anatomy-and-physiology

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Clinical application of 2.16% hypertonic saline solution to correct the blood sodium concentration in diarrheic calves with hyponatremia

Mitsuhide Nakagawa 1Kenji Tsukano 2Yoshiki Murakami 2Marina Otsuka 2Kazuyuki Suzuki 2Hiroetsu Suzuki 3Affiliations expand

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The aim of this study was to examine whether 2.16% hypertonic saline solution (HSS) is useful for the treatment of diarrheic calves with hyponatremia. Eleven of 13 female Holstein calves exhibiting moderate diarrhea and hyponatremia received 1,250 ml of 2.16% HSS over 15 min regardless of body weight. The remaining two calves that were unable to stand and had severe hyponatremia received 2,500 ml of 2.16% HSS intravenously over 30 min. As a result, hyponatremia in all diarrheic calves was significantly improved by the administration of 2.16% HSS from 122.2 ± 7.0 mEq/l at pre to 134.8 ± 3.7 mEq/l at post, which was above the threshold of 132 mEq/l for hyponatremia. Therefore, 2.16% HSS may be useful for hyponatremia in calves with diarrhea.

Diabetes prevalence and outcomes in hospitalized cardiorenal-syndrome patients with and without hyponatremia

Rainer U Pliquett 1 2Katrin Schlump 3Andreas Wienke 4Babett Bartling 5Michel Noutsias 6Alexander Tamm 6 7Matthias Girndt 3Affiliations expand

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Background: Hyponatremia is known to be associated with a worse patient outcome in heart failure. In cardiorenal syndrome (CRS), the prognostic role of concomitant hyponatremia is unclear. We sought to evaluate potential risk factors for hyponatremia in patients with CRS presenting with or without hyponatremia on hospital admission.

Methods: In a retrospective study, we investigated 262 CRS patients without sepsis admitted to the University Hospital Halle over a course of 4 years. CRS diagnosis was derived from an electronic search of concomitant diagnoses of acute or chronic (NYHA 3-4) heart failure and acute kidney injury (AKIN 1-3) or chronic kidney disease (KDIGO G3-G5nonD). A verification of CRS diagnosis was done based on patient records. Depending on the presence (Na < 135 mmol/L) or absence (Na ≥ 135 mmol/L) of hyponatremia on admission, the CRS patients were analyzed for comorbidities such as diabetes, presence of hypovolemia on admission, need for renal replacement therapy and prognostic factors such as in-hospital and one-year mortality.

Results: Two hundred sixty-two CRS patients were included in this study, thereof, 90 CRS patients (34.4%) with hyponatremia (Na < 135 mmol/L). The diabetes prevalence among CRS patients was high (> 65%) and not related to the serum sodium concentration on admission. In comparison to non-hyponatremic CRS patients, the hyponatremic patients had a lower serum osmolality, hypovolemia was more prevalent (41.1% versus 16.3%, p < 0.001). As possible causes of hypovolemia, diarrhea, a higher number of diuretic drug classes and higher diuretic dosages were found. Hyponatremic and non-hyponatremic CRS patients had a comparable need for renal-replacement therapy (36.7% versus 31.4%) during the hospital stay. However, after discharge, relatively more hyponatremic CRS patients on renal replacement therapy switched to a non-dialysis therapy regimen (50.0% versus 22.2%). Hyponatremic CRS patients showed a trend for a higher in-hospital mortality (15.6% versus 7.6%, p = 0.054), but no difference in the one-year mortality (43.3% versus 40.1%, p = 0.692).

Conclusions: All CRS patients showed a high prevalence of diabetes mellitus and a high one-year mortality. In comparison to non-hyponatremic CRS patients, hyponatremic ones were more likely to have hypovolemia, and had a higher likelihood for temporary renal replacement therapy.

Hypothyroidism-induced Acute Kidney Injury and Hyponatremia

Muhammad Tariq Shakoor 1Kaelo Moahi 2Douglas Shemin 1Affiliations expand

  • PMID: 32872693

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Thyroid hormones affect every organ system in the body including renal development and physiology, and electrolyte and water homeostasis. These effects happen as a consequence of the combination of direct effects of thyroid hormones on renal tubules and hemodynamic effects of thyroid hormones. As a consequence, both hypothyroidism and hyperthyroidism significantly affect renal function. This case describes a patient with hypothyroidism-related acute kidney injury without rhabdomyolysis, and no additional precipitating factor. While there are many case reports describing hypothyroidism-related rhabdomyolysis leading to acute kidney injury, there are only a handful of case reports on hypothyroidism-related acute kidney injury without rhabdomyolysis.

Tolvaptan treatment in hyponatremia due to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH): effects on survival in patients with cancer

Irem Bilgetekin 1Ismail Erturk 2Fatma Bugdayci Basal 1Cengiz Karacin 3Nuri Karadurmus 2Berna Oksuzoglu 1Umut Demirci 4Affiliations expand

Purpose: To investigate the clinical outcomes of patients with hyponatremia who received supportive treatment or tolvaptan plus supportive treatment and the effects of treatment and other variables on overall survival METHODS: This study included oncology patients who were hospitalized at two oncology centers between January 1, 2016 and December 31, 2019 for hyponatremia (sodium levels < 135 mEq/L) and who received tolvaptan plus supportive treatment (n = 22) or supportive treatment only (n = 42).

Results: The median age of all the patients was 59 years (range 26-85) and 64.1% of the patients were male. There was no statistically significant difference between patients in the tolvaptan plus supportive treatment (TpST) group and the supportive treatment only (ST) group in terms of gender and age (p > 0.05). In the TpST group, recovery days of the hyponatremia after treatment and the length of hospital stay was shorter and hyponatremia symptoms and hospital complications were less frequent compared to the ST group (p < 0.05). There was no significant difference between the TpST group and the ST group in terms of overall survival (OS). OS was shorter in men who were non-responders to hyponatremia treatment and had recurrent hyponatremia. Multivariable analysis showed that normal sodium levels after treatment decreased the risk of death.

Conclusion: In the treatment of hyponatremia in cancer patients, TpST was found to have more positive effects on blood sodium levels, length of hospital stay, hospital complications, and hyponatremia symptoms compared to ST. A decreased risk of death was observed in patients with normal sodium levels after treatment.

Redefined hyponatremia as a marker to exclude the diagnosis of anastomotic leakage after colorectal cancer surgery

Guochao Zhang 1Rui Lian 2Lichao Sun 2Haibin Liu 1Yan Wang 1Lei Zhou 1Affiliations expand

Objective: Our objective was to investigate the association between anastomotic leakage (AL) and hyponatremia after colorectal cancer surgery.

Methods: All anastomoses in colorectal cancer surgery performed in our hospital between January 2015 and December 2017 were retrospectively identified. According to the diagnostic criteria of AL, the patients were divided into an AL group and a no anastomotic leakage (NAL) group.

Results: We reviewed records of 498 consecutive colorectal cancer patients. The total incidence of AL was 5.4%. Postoperative serum sodium levels differed significantly: 137.63 ± 4.29 and 139.81 ± 3.41 mmol/L in the AL and NAL groups, respectively. By using area under the receiver-operating characteristic (auROC) curves, we determined the optimum postoperative serum sodium cut-off to be 139.5 mmol/L and redefined hyponatremia as postoperative serum sodium <139.5 mmol/L. Redefined hyponatremia had an auROC of 0.65, corresponding to a 97.2% negative predictive value. The negative predictive value reached 99.1% when serum sodium level was combined with leukocytosis. Multivariable analysis found that redefined hyponatremia (odds ratio, 1.176) was an independent predictive factor for AL.

Conclusions: Redefined hyponatremia has good negative predictive value for AL diagnosis after colorectal cancer surgery and could be used as a marker to exclude the diagnosis.

Keywords: Hyponatremia; anastomotic leakage; biomarker; colorectal cancer; leukocytosis; postoperative serum sodium level.

Prevalence and Impact of Hyponatremia in Patients With Coronavirus Disease 2019 in New York City

Jennifer A Frontera 1Eduard Valdes 1Joshua Huang 2Ariane Lewis 1Aaron S Lord 1Ting Zhou 1D Ethan Kahn 1Kara Melmed 1Barry M Czeisler 1Shadi Yaghi 1Erica Scher 1Thomas Wisniewski 1 3 4Laura Balcer 1Elizabeth Hammer 5Affiliations expand

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Objectives: Hyponatremia occurs in up to 30% of patients with pneumonia and is associated with increased morbidity and mortality. The prevalence of hyponatremia associated with coronavirus disease 2019 and the impact on outcome is unknown. We aimed to identify the prevalence, predictors, and impact on outcome of mild, moderate, and severe admission hyponatremia compared with normonatremia among coronavirus disease 2019 patients.

Design: Retrospective, multicenter, observational cohort study.

Setting: Four New York City hospitals that are part of the same health network.

Patients: Hospitalized, laboratory-confirmed adult coronavirus disease 2019 patients admitted between March 1, 2020, and May 13, 2020.

Interventions: None.

Measurements and main results: Hyponatremia was categorized as mild (sodium: 130-134 mmol/L), moderate (sodium: 121-129 mmol/L), or severe (sodium: ≤ 120 mmol/L) versus normonatremia (135-145 mmol/L). The primary outcome was the association of increasing severity of hyponatremia and in-hospital mortality assessed using multivariable logistic regression analysis. Secondary outcomes included encephalopathy, acute renal failure, mechanical ventilation, and discharge home compared across sodium levels using Kruskal-Wallis and chi-square tests. In exploratory analysis, the association of sodium levels and interleukin-6 levels (which has been linked to nonosmotic release of vasopressin) was assessed. Among 4,645 patient encounters, hyponatremia (sodium < 135 mmol/L) occurred in 1,373 (30%) and 374 of 1,373 (27%) required invasive mechanical ventilation. Mild, moderate, and severe hyponatremia occurred in 1,032 (22%), 305 (7%), and 36 (1%) patients, respectively. Each level of worsening hyponatremia conferred 43% increased odds of in-hospital death after adjusting for age, gender, race, body mass index, past medical history, admission laboratory abnormalities, admission Sequential Organ Failure Assessment score, renal failure, encephalopathy, and mechanical ventilation (adjusted odds ratio, 1.43; 95% CI, 1.08-1.88; p = 0.012). Increasing severity of hyponatremia was associated with encephalopathy, mechanical ventilation, and decreased probability of discharge home (all p < 0.001). Higher interleukin-6 levels correlated with lower sodium levels (p = 0.017).

Conclusions: Hyponatremia occurred in nearly a third of coronavirus disease 2019 patients, was an independent predictor of in-hospital mortality, and was associated with increased risk of encephalopathy and mechanical ventilation.

Severe Hyponatremia Precipitated by Acute Urinary Retention in a Patient with Psychogenic Polydipsia

C M H Hilton 1 2L Boesby 1K E Nelveg-Kristensen 1Affiliations expand

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A woman in her late sixties presented with severe hyponatremia and acute kidney injury (AKI) as consequence of psychogenic polydipsia and acute urinary retention due to urinary tract infection. Urinary catheterization promptly drained 5.5 L of urine with resulting polyuria, leading to an initial swift raise in plasma (P) sodium concentration, disregarding the course of fluid resuscitation. After the polyuric phase, normal range P-sodium levels were reestablished by oral water restriction. Treatment with psychoactive drugs, e.g., zuclopentixol, may have contributed to the severity of the condition. There are few published reports regarding water intoxication and urinary retention, but none reflecting severe hyponatremia precipitated by acute urinary retention in a patient with polydipsia. By this report, we illustrate the detrimental consequences on water and electrolyte homeostasis of urinary retention and polydipsia resulting in acute water intoxication. The purpose of presenting this case is firstly to draw attention to the potentially fatal combination of polydipsia and postrenal acute kidney injury, where the kidneys are unable to correct the enormous excess water, then to focus on the difficulty in correcting hypervolemic hyponatraemia in the context of polyuria after relief of urinary retention, and finally, to point out that patients in treatment with antipsychotics may have further worsening of electrolyte derangement.