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Introduction: Disturbances in plasma sodium levels are a major complication following recent resections of craniopharyngiomas in children. They must be properly managed to avoid neurological sequelae. We aimed to describe the variations and characteristics of postoperative natremia in children who had undergone a first craniopharyngioma resection with a particular focus on the frequency of triphasic syndrome in these patients., Methods: Paediatric patients with craniopharyngiomas who underwent a first surgical resection in the neurosurgery department of the Hôpital Femme Mère Enfant (Lyon, France) between January 2010 and September 2021 were included in the present study and the medical records were analysed retrospectively., Results: A total of 26 patients were included. Of these, 17 (65.4%) had a postoperative course characterised by the occurrence of both initial diabetes insipidus (DI) and hyponatremia a few days later. Eight patients (30.8%) presented then with isolated and persistent DI. Patients with the triphasic syndrome had a significantly higher grade of Puget classification on MRI (1 and 2), compared to the other patients., Conclusion: Dysnatremia is common after craniopharyngioma resections in children. This immediate postoperative complication is particularly difficult to manage and requires rapid diagnosis and prompt initiation of medical treatment to minimize fluctuations in sodium levels and avoid neurological sequelae., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Maintenance intravenous fluids are the most frequently ordered medications for hospitalized children. Since the American Association of Pediatrics published national guidelines, there has been an increased reflexive use of isotonic solutions, especially 0.9% saline, as a prophylaxis against hyponatremia. In this educational review, we discuss the potential deleterious effects of using 0.9% saline, including the development of hyperchloremia, metabolic acidosis, acute kidney injury, hyperkalemia, and a proinflammatory state. Balanced solutions with anion buffers cause relatively minimal harm when used in most children. While the literature supporting one fluid choice over the other is variable, we highlight the benefits of balanced solutions over saline and the importance of prescribing fluid therapy that is individualized for each patient., (© 2024. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Purpose: To investigate the clinical characteristics of the syndrome of inappropriate antidiuretic hormone (SIADH) associated with nasal and paranasal malignant tumors., Methods: Patients with locally advanced or recurrence/metastatic malignant tumors of the nasal and paranasal sinuses were included. The SIADH was diagnosed according to the diagnostic criteria. The clinical characteristics of SIADH patients were retrospectively analyzed., Results: Six patients (6/188, 3.2%) met the diagnostic criteria of SIADH, including four olfactory neuroblastoma (4/26, 15.4%), one neuroendocrine carcinoma (1/9, 11.1%), and one squamous cell carcinoma (1/63, 1.6%). Five patients (83.3%) had severe hyponatremia; however, the hyponatremia could be improved by fluid restriction or tolvaptan. Three patients' SIADH were recovered during the chemotherapy and the other three were recovered after the surgery., Conclusion: The incidence of SIADH associated with nasal and paranasal malignant tumors is relatively more common in olfactory neuroblastoma and neuroendocrine carcinoma. The hyponatremia caused by SIADH may be corrected by fluid restriction or tolvaptan, and the SIADH may be recovered through anti-tumor therapy., (© 2023. The Author(s).)

Background: Iatrogenic hyponatremia is a common complication following intravenous maintenance fluid therapy (IV-MFT) in hospitalized children. Despite the American Academy of Pediatrics' 2018 recommendations, IV-MFT prescribing practices still vary considerably., Objectives: This meta-analysis aimed to compare the safety and efficacy of isotonic versus hypotonic IV-MFT in hospitalized children., Data Sources: We searched PubMed, Scopus, Web of Science, and Cochrane Central from inception to October 1, 2022., Study Eligibility Criteria: We included randomized controlled trials (RCTs) comparing isotonic versus hypotonic IV-MFT in hospitalized children, either with medical or surgical conditions. Our primary outcome was hyponatremia following IV-MFT. Secondary outcomes included hypernatremia, serum sodium, serum potassium, serum osmolarity, blood pH, blood sugar, serum creatinine, serum chloride, urinary sodium, length of hospital stay, and adverse outcomes., Study Appraisal and Synthesis Methods: Random-effects models were used to pool the extracted data. We performed our analysis based on the duration of fluid administration (i.e., ≤ 24 and > 24 h). The Grades of Recommendations Assessment Development and Evaluation (GRADE) scale was used to evaluate the strength and level of evidence for recommendations., Results: A total of 33 RCTs, comprising 5049 patients were included. Isotonic IV-MFT significantly reduced the risk of mild hyponatremia at both ≤ 24 h (RR = 0.38, 95% CI [0.30, 0.48], P < 0.00001; high quality of evidence) and > 24 h (RR = 0.47, 95% CI [0.37, 0.62], P < 0.00001; high quality of evidence). This protective effect of isotonic fluid was maintained in most examined subgroups. Isotonic IV-MFT significantly increased the risk of hypernatremia in neonates (RR = 3.74, 95% CI [1.42, 9.85], P = 0.008). In addition, it significantly increased serum creatinine at ≤ 24 h (MD = 0.89, 95% CI [0.84, 0.94], P < 0.00001) and decreased blood pH (MD = -0.05, 95% CI [-0.08 to -0.02], P = 0.0006). Mean serum sodium, serum osmolarity, and serum chloride were lower in the hypotonic group at ≤ 24 h. The two fluids were comparable in terms of serum potassium, length of hospital stay, blood sugar, and the risk of adverse outcomes., Limitations: The main limitation of our study was the heterogeneity of the included studies., Conclusions and Implications of Key Findings: Isotonic IV-MFT was superior to the hypotonic one in reducing the risk of iatrogenic hyponatremia in hospitalized children. However, it increases the risk of hypernatremia in neonates and may lead to renal dysfunction. Given that the risk of hypernatremia is not important even in the neonates, we propose to use balanced isotonic IV-MFT in hospitalized children as it is better tolerated by the kidneys than 0.9% saline., Systematic Review Registration Number: CRD42022372359. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information., (© 2023. The Author(s).)

Purpose: Distinguishing between perforated/gangrenous from uncomplicated appendicitis in children helps management. We evaluated hyponatremia as a new diagnostic marker for perforated/gangrenous appendicitis in children., Methods: A prospective study including all children with acute appendicitis who underwent appendectomy at our institution from May 2021 to May 2023. Medical history and clinical criteria were analyzed. All blood samples were taken upon admission including serum inflammatory markers and electrolytes. Patients were divided into two groups (Group I: uncomplicated and Group II: perforated/gangrenous), and data between both groups were compared., Results: The study included 153 patients [Group I: 111 (73%), Group II: 42 (27%)]. Mean serum sodium concentration in children with perforated/gangrenous appendicitis was significantly lower compared to children with uncomplicated appendicitis (131.8 mmol/L vs. 138.7 mmol/L; p < 0.001). The ROC curve of preoperative sodium level to differentiate between perforated/gangrenous and uncomplicated appendicitis revealed an AUC of 0.981. The cut-off-value of sodium level < 135 mmol/L identified perforated/gangrenous appendicitis with a sensitivity of 94% and a specificity of 91% (p < 0.001). Predictive factors of perforated/gangrenous appendicitis were: age less than 5 years (12% vs. 3%; p = 0.02), experiencing symptoms for more than 24 h (100% vs. 58%; p < 0.001), body temperature more than 38.5 °C (52% vs. 13%; p < 0.001), a serum sodium level less than 135 mmol/L (90% vs. 6%; p < 0.001), and a CRP serum level more than 50 mg/L (71% vs. 17%; p < 0.001)., Conclusions: Hyponatremia, upon admission, is a novel, objective biochemical marker that can identify perforated/gangrenous appendicitis in children. We advocate that the assessment of serum sodium level should be added to the diagnostic algorithm in children with suspected acute appendicitis. Surgical intervention in patients with hyponatremia should not be delayed, and non-operative management should be avoided., (© 2023. The Author(s).)

Background: Experience with nasogastric administration of oral DDAVP [desamino-D-arginine-8-vasopressin] lyophilisate (ODL) for central diabetes insipidus (CDI) in disabled children with swallowing coordination difficulties is limited., Objective: We aimed to assess the safety and efficacy of nasogastric use of ODL in disabled children with CDI. Time to serum sodium normalisation was compared with that of children with normal intellect and CDI treated with sublingual DDAVP., Methods: Clinical, laboratory and neuroimaging characteristics were evaluated for 12 disabled children with CDI treated with ODL through nasogastric tube at Dr Behcet Uz Children's Hospital, Turkey, between 2012 and 2022., Results: Six boys and six girls with a mean (±SD) age of 43 (± 40) months were evaluated. These children (mean [±SD] weight standard deviation score [SDS] - 1.2 ± 1.7; mean [±SD] height SDS - 1.3 ± 1.4) presented with failure to thrive, irritability, prolonged fever, polyuria and hypernatraemia (mean serum sodium 162 [±3.6] mEq/L). At diagnosis, mean serum and urine osmolality were 321 (± 14) mOsm/kg and 105 (± 7.8) mOsm/kg, respectively. Arginine vasopressin (AVP) levels were undetectable (< 0.5 pmol/L) at diagnosis in all patients. Nasogastric tube administration of DDAVP lyophilisate (120 µg/tablet) dissolved in water (10 mL) was commenced at a dose of 1-5 µg/kg/day in two divided doses together with controlled water intake to avoid hyponatraemia. The frequency and dose of DDAVP were titrated based on urine output and serum sodium concentration. Serum sodium declined at a rate of 0.11 ± 0.03 mEq/L/h and reached normal range in a mean duration of 174 ± 46.5 h. Serum sodium declined faster in children with normal intellect and CDI treated with sublingual DDAVP (1.28 ± 0.39 mEq/L/h; p = 0.0003). Three disabled children needed rehospitalisation because of hypernatraemia due to unintentional DDAVP omission by caregivers. No episode of hyponatraemia was observed. Weight gain and growth were normal during the median (± interquartile range) follow-up duration of 32 ± 67 months., Conclusions: Nasogastric administration of oral DDAVP lyophilised formulation was safe and effective in the treatment of CDI in disabled children in this small retrospective series., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Purpose: Hyponatremia after craniotomy can be associated with increased morbidity. However, the incidence of and factors associated with post-craniotomy hyponatremia in children are not known., Methods: We performed a retrospective cohort study of patients aged 0-21 years who underwent craniotomy in 2017-2019 at a single center to determine the incidence of and to identify risk factors for hyponatremia after craniotomy. Indications for craniotomy included tumors (excluding craniopharyngioma), epilepsy, intracranial infection, trauma, craniofacial, suboccipital decompression for the treatment of Chiari malformation, and cerebrovascular disease. Hyponatremia was defined as a serum sodium level ≤ 135 mEq/L any time during the postoperative hospital stay. Statistical significance was defined a priori at p < 0.05., Results: Postoperative hyponatremia occurred in 61 (25%) of 240 children. On univariate analysis, hyponatremia was associated with younger age (8.5 vs 6.3 years, p = 0.01), use of preoperative anti-epileptic drugs (p = 0.02), need for blood transfusion (p = 0.02), government/private insurance (p = 0.04), and pre-existing hydrocephalus, defined as the requirement for permanent cerebrospinal fluid (CSF) diversion (p = 0.04). On multivariate analysis, only hydrocephalus (OR 2.95, 95% CI 1.03-8.40) remained statistically significant. Hyponatremia most occurred on the first postoperative day, with normonatremia achieved in a median of 14 (IQR 9.8-24.3) h. Hyponatremia was significantly associated with longer length of stay (median 8 vs 3 days, p < 0.01)., Conclusion: Hyponatremia was present in 25% of children after craniotomy. Preoperative hydrocephalus as an independent risk factor for hyponatremia after craniotomy., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Hyponatremia is an independent prognostic factor for mortality; however, the reason for this remains unclear. An observed relationship between hyponatremia and the development of acute kidney injury (AKI) has been reported in certain disease states, but hyponatremia has not been evaluated as a predictor of AKI in critically ill patients or children., Methods: This is a single-center retrospective cohort study of critically ill children admitted to a tertiary care center. We performed regression analysis to assess the association between hyponatremia at ICU admission and the development of new or worsening stage 2 or 3 (severe) AKI on days 2-3 following ICU admission., Results: Among the 5057 children included in the study, early hyponatremia was present in 13.3% of children. Severe AKI occurred in 9.2% of children with hyponatremia compared to 4.5% of children with normonatremia. Following covariate adjustment, hyponatremia at ICU admission was associated with a 75% increase in the odds of developing severe AKI when compared to critically ill children with normonatremia (aOR 1.75, 95% CI 1.28-2.39). Evaluating sodium levels continuously, for every 1 mEq/L decrease in serum sodium level, there was a 0.05% increase in the odds of developing severe AKI (aOR 1.05, 95% CI 1.02-1.08). Hyponatremic children who developed severe AKI had a higher frequency of kidney replacement therapy, AKI or acute kidney disease at hospital discharge, and hospital mortality when compared to those without., Conclusions: Hyponatremia at ICU admission is associated with the development of new or worsening AKI in critically ill children. A higher resolution version of the Graphical abstract is available as Supplementary information., (© 2022. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Background: The use of hypotonic fluid, such as 0.45% saline, following kidney transplantation (KT) in children is associated with a high incidence of electrolyte imbalance, especially hyponatraemia. This can result in serious adverse events, such as cerebral oedema and seizures. The aim of this study was to investigate the incidence of electrolyte disturbance in children when 0.9% saline was the intravenous fluid used in the first 72 h following KT., Methods: This is a retrospective, observational study of 50 consecutive KT undertaken between January 2017 and January 2019 at a single centre., Results: The median age at KT was 9.2 years (IQR 4-14) and 16 (32%) were females. Thirty-two (64%) were living related donor (LRD) KT and 22 (44%) were carried out in children < 20 kg. The mean volume of fluid administered intra-operatively, and on Day 1, Day 2 and Day 3, were 73 ml/kg, 124 ml/kg, 97 ml/kg and 86 ml/kg, respectively. Hyponatraemia was noted in 4%, hypernatraemia in 18%, hyperkalaemia in 18%, hyperchloraemia in 68% and low bicarbonate was seen in 88%. Fifteen percent of the children had an episode of hyperglycaemia. None of the children developed symptomatic dyselectrolytaemia. There was delayed graft function (DGF) in 4 (8%) recipients - all deceased donor (DD) KT, including 2 who received donations after circulatory death., Conclusions: While the use of 0.9% saline is associated with a high incidence of electrolyte disturbances, including hyperkalaemia, it reduces the risk of hyponatraemia. None of the children developed a symptomatic electrolyte abnormality. A higher resolution version of the Graphical abstract is available as Supplementary information., (© 2021. Crown.)

Hyponatremia, especially if acute and severe, can be a life-threatening condition. Several conditions can trigger hyponatremia. In this review, we will discuss two conditions that can determine euvolemic hyponatremia: the cerebral/renal salt wasting (CRSW) syndrome and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), including the two subtypes: reset osmostat (RO) and nephrogenic syndrome of inappropriate antidiuresis (NSIAD) and their differential diagnoses. Despite the passage of over 70 years since its first description, to date, the true etiopathogenesis of CRSW syndrome, a rare cause of hypovolemic/euvolemic hyponatremia, is almost unknown. SIADH, including RO and NSIAD, is sometimes difficult to differentiate from CRSW syndrome; in its differential diagnosis, the clinical approach based on the evaluation of the extracellular volume (ECV) was proven insufficient. We therefore suggest a simple diagnostic algorithm based on the assessment of the degree of hyponatremia, urinary osmolality, and the assessment of the fraction of urate excretion (FEUa) in conditions of hyponatremia and after serum sodium correction, to be applied in children over 1 year of life., (© 2021. The Author(s).)

Background: Hypotonic fluids have been associated with hospital-acquired hyponatremia. The incidence of life-threatening severe hyponatremia associated with hypotonic fluids has not been evaluated., Methods: This was a population-based cohort study of 46,518 acutely ill children 15 years of age or under who visited the pediatric emergency department (ED) at Oulu University Hospital, Finland, between 2007 and 2017. We retrieved all electrolyte measurements from the comprehensive electronic laboratory system and reviewed medical records for all patients with severe hyponatremia., Results: The overall occurrence of severe hyponatremia (serum sodium < 125 mmol/L) was found in 27 out of 46,518 acutely ill children (0.06%, 95% confidence interval 0.04-0.08%). After admission, severe hyponatremia developed in seven of 6,984 children receiving moderately hypotonic fluid therapy (0.1%, 95% confidence interval 0.04-0.2%), usually within 8 h of admission. All children who developed severe hyponatremia during hospitalization were severely ill., Conclusion: In this register-based cohort study of children presenting to the ED, severe hyponatremia developed in one of 998 acutely ill children receiving moderately hypotonic fluid therapy. A higher resolution version of the Graphical abstract is available as Supplementary information., (© 2021. The Author(s).)

Background: Tolvaptan is a selective oral vasopressin V2-receptor antagonist. Some data have implicated stimulation of arginine vasopressin (AVP) as an important factor in oedema formation in a rodent model of nephrotic syndrome (NS) and adult NS patients. We report case of pediatric NS with severe hyponatremia efficiently treated by tolvaptan., Case/diagnosis - Treatment: A 22-month-old girl presented first with NS. She remained nephrotic after a 30-day course of oral steroids. Tacrolimus was inefficient and there was no response to plasma exchanges (15 sessions on a daily basis). She had severe oedema and ascites. Thus, in addition to immunosuppressive therapy, she received diuretics, furosemide 5 mg/kg/day, and amiloride 1 mg/kg/day, and required water restriction. She was hypertensive and was treated with a full dose of calcium inhibitor (amlodipine 0.5 mg/kg/day). After2 months of treatment, serum sodium reached 116 mmol/L and urinary osmolarity 547 mosmol/L, suggesting an inappropriate AVP secretion. Tolvaptan was introduced at 0.3 mg/kg/day and progressively increased to 3 mg/kg/day on day 4, leading to a partial correction of serum sodium (130 mmol/l) and a urinary osmolarity decrease to 90 mosmol/L. Tolvaptan was then continued at the dose of 3 mg/kg/day with unchanged serum sodium, without hypernatremia or dehydration. Her weight decreased from 14.8 k to 14 k, but oedema still persisted., Conclusion: Tolvaptan was very efficient in this case of hyponatremia associated with steroid-resistant NS. Tolvaptan should be considered in the management of therapy-resistant hyponatremia in patients with NS.

Nephrogenic syndrome of inappropriate antidiuresis (NSIAD), first described in 2005, is a rare genetic X-linked disease, presenting with hyponatremia, hyposmolarity, euvolemia, inappropriately concentrated urine, increased natriuresis, and undetectable or very low arginine-vasopressine (AVP) circulating levels. It can occur in neonates, infants, or later in life. NSIAD must be early recognized and treated to prevent severe hyponatremia, which can show a dangerous impact on neonatal outcome. In fact, it potentially leads to death or, in case of survival, neurologic sequelae. This review is an update of NSIAD 12 years after the first description, focusing on reported cases of neonatal and infantile onset. The different molecular patterns affecting the AVP receptor 2 (V2R) and determining its gain of function are reported in detail; moreover, we also provide a comparison between the different triggers involved in the development of hyponatremia, the evolution of the symptoms, and modality and efficacy of the different treatments available.

Purpose: Hyponatremia and bone metastasis (BMs) are known as negative prognostic factors in patients affected by metastatic non-small cell lung cancer (NSCLC). Hyponatremia is associated with higher risk of osteoporosis and bone fracture, but no data are available about the relationship between hyponatremia and bone metastasis. This study aims to analyze the prognostic impact of hyponatremia in NSCLC patients with bone metastases., Methods: We retrospectively collected data about advanced NSCLC patients. Survival curves were estimated using Kaplan-Meier method, and comparisons were made using chi-square test., Results: Six hundred forty-seven patients were enrolled into the study. BMs were present in 264 patients (41%) at diagnosis, while hyponatremia appeared in 237 (37%) patients during the first-line treatment. Patients without BMs had a median overall survival (mOS) of 15.9 months (95% CI 14.1-17.9) versus 11.4 months (95% CI 9.4-13.4) for patients with BMs (p = 0.001). Eunatremic patients had a better outcome (mOS 16.3 months, 95% CI 14.6-18.0 vs 10.3 months, 95% I 7.6-12.8, p = 0.003). Considering the two variables, patients with BMs and hyponatremia had a mOS of 10.1 months (95% CI 4.3-15.9), patients with hyponatremia without BMs 11.9 months (95% CI 11.4-12.4), while mOS was 13.1 months (95% CI 12.0-14.2) for eunatremic patients with BMs versus 17.1 months (95% CI 15.2-19.1) in eunatremic patients without BMs (p = 0.0020). Hyponatremic patients developed metachronous BMs significantly earlier (3.73 vs 5.76 months, p = 0.0187)., Conclusions: Our study showed that hyponatremia is an important prognostic factor and it should be necessarily considered to enhance the management of NSCLC patients with BMs.

Objectives: (1) Evaluate mortality rate in patients with Shiga toxin-producing Escherichia coli hemolytic uremic syndrome, (2) determine the leading causes of death, and (3) identify predictors of mortality at hospital admission., Methods: We conducted a multicentric, observational, retrospective, cross-sectional study. It included patients under 18 years old with Shiga toxin-producing Escherichia coli hemolytic uremic syndrome hospitalized between January 2005 and June 2016. Clinical and laboratory data were obtained from the Argentine National Epidemiological Surveillance System of Hemolytic Uremic Syndrome. Clinical and laboratory variables were compared between deceased and non-deceased patients. Univariate and multivariate analyses were performed. ROC curves and area under the curve were obtained., Results: Seventeen (3.65%) out of the 466 patients died, being central nervous system involvement the main cause of death. Predictors of death were central nervous system involvement, the number of days since the beginning of diarrhea to hospitalization, hyponatremia, high hemoglobin, high leukocyte counts, and low bicarbonate concentration on admission. In the multivariate analysis, central nervous system involvement, sodium concentration, and hemoglobin were independent predictors. The best cut off for sodium was ≤ 128 meq/l and for hemoglobin ≥ 10.8 g/dl., Conclusions: Mortality was low in children with Shiga toxin-producing Escherichia coli hemolytic uremic syndrome, being central nervous system involvement the main cause of death. The best mortality predictors found were central nervous system involvement, hemoglobin, and sodium concentration. Hyponatremia may be a new Shiga toxin-producing Escherichia coli hemolytic uremic syndrome mortality predictor.

Hyponatremia is associated with bone demineralization. We hypothesized that, during hyponatremia, calciuria and calcium balance depend on volemic status. We evaluated calciuria in patients with hyponatremia, secondary to SIAD or hypovolemia. Patients with SIAD exhibited a volemic expansion that was associated with hypercalciuria. Calciuria was proportional to markers of volemia., Introduction: Chronic mild hyponatremia has been associated with bone demineralization of unknown mechanisms. During chronic hyponatremia, arginine-vasopressin secretion can result from hypovolemia or from syndrome of inappropriate anti-diuresis (SIAD) that leads to a slightly volemic expansion. Since volemia determines renal calcium excretion and balance, we evaluated calcium homeostasis in patients with chronic hyponatremia, related to SIAD or to hypovolemia., Methods: We retrospectively included all patients referred to our Department between May 2006 and May 2014 for hyponatremia, resulting from SIAD or chronic hypovolemia. None had edema, cirrhosis, cardiac, or renal insufficiency. Exploration included estimation of volemia, extracellular fluid volume (ECFV) measurement with inulin, and calcium homeostasis., Results: In total, the SIAD and hypovolemic groups included 22 and 7 patients, respectively. The SIAD group exhibited signs of increased volemia: higher glomerular filtration rate, higher fractional excretion of uric acid, and lower plasma renin. ECFV exceeded that of the hypovolemic group and was above usual values. There was no difference between the two groups regarding plasma calcium, PTH, and vitamin D. However, in the SIAD group, calciuria was higher than in the hypovolemic group, reaching levels of hypercalciuria. Furthermore, there was a positive correlation between calciuria and markers of volemia., Conclusions: Our results show that SIAD results in a volemic expansion tendency that is associated with a decrease in renal calcium reabsorption and thus hypercalciuria, whereas in the hypovolemic group, calciuria was not increased. Therefore, renal loss of calcium and bone demineralization in SIAD patients could be partly induced by volemic expansion.

Intravenous (IV) fluids are used ubiquitously when children undergo surgical procedures. Until recently, Holliday and Segar's guidelines for calculating maintenance fluids dictated fluid management strategies in postoperative pediatric patients. An increased recognition of hospital-acquired hyponatremia and its associated morbidity has led to a critical re-examination of IV fluid management in this population. Postsurgical patients are at high risk of developing hyponatremia due to the presence of non-osmotic stimuli for antidiuretic hormone release. Recent studies have established that, as they are administered in current practice, hypotonic maintenance fluids are associated with increased rates of hyponatremia. The best available data demonstrate that administration of isotonic fluid reduces hyponatremic risk. In this review, we discuss the collective data available on the subject and offer guidelines for fluid management and therapeutic monitoring.

Hyponatremia (Na ˂ 135 mmol/l) is the most frequent electrolyte disorder in clinical practice, and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the commonest cause of hyponatremia in cancer patients. Correcting hyponatremia in these patients can reduce morbidity and mortality, increase the response to anti-cancer agents, and help reduce hospital length of stay and costs. Tolvaptan is an oral medication used to treat SIADH-related hyponatremia patients that needs to be initiated at hospital so patients can have their serum sodium monitored. If tolvaptan could be initiated in hospital day care units (DCUs), performing the same tests, hospitalization could be avoided, quality of life improved, and costs reduced. This is the first publication where a panel of oncologists are sharing their experience and making some recommendations with the use of tolvaptan to treat SIADH-related hyponatremia in DCU after collecting and examining 35 clinical cases with these type of patients. The conclusion from this retrospective observational analysis is that the use of tolvaptan in DCU is safe and effective in the therapeutic management of SIADH-related hyponatremia.

Background: Hyponatremic hypertensive syndrome (HHS) is characterized by unilateral renal artery stenosis with secondary hypertension and glomerular and tubular dysfunction due to hyperfiltration and activation of the renin-angiotensin system (RAS)., Case-Diagnosis/treatment: We describe four children with HHS. All presented with polyuria and polydipsia, electrolyte disturbances, metabolic alkalosis, variable tubular dysfunction, and nephrotic range proteinuria along with hypertension. Interestingly, in one patient, glomerular and tubular abnormalities preceded the development of hypertension. All symptoms resolved after the underlying renal ischemia was corrected by percutaneous angioplasty., Conclusion: Hyponatremic hypertensive syndrome may be more common in children than previously thought. Clinicians should be alert of the signs and symptoms because cure is possible with timely diagnosis and treatment.

Hypotonic hyponatremia, a serious and recognized complication of any intracranial disorder, results from extra-cellular fluid volume depletion, inappropriate anti-diuresis or renal salt-wasting. The putative mechanisms by which intracranial disorders might lead to renal salt-wasting are either a disrupted neural input to the kidney or the elaboration of a circulating natriuretic factor. The key to diagnosis of renal salt-wasting lies in the assessment of extra-cellular volume status: the central venous pressure is currently considered the yardstick for measuring fluid volume status in subjects with intracranial disorders and hyponatremia. Approximately 110 cases have been reported so far in subjects ≤18 years of age (male: 63%; female: 37%): intracranial surgery, meningo-encephalitis (most frequently tuberculous) or head injury were the most common underlying disorders. Volume and sodium repletion are the goals of treatment, and this can be performed using some combination of isotonic saline, hypertonic saline, and mineralocorticoids (fludrocortisone). It is worthy of a mention, however, that some authorities contend that cerebral salt wasting syndrome does not exist, since this diagnosis requires evidence of a reduced arterial blood volume, a concept but not a measurable variable.

Post-operative hyponatremia is a common complication in children which results from hypotonic fluid administration in the presence of arginine vasopressin (AVP) excess. We evaluated the relationship between the change in serum sodium and AVP levels following percutaneous renal biopsy in children receiving either hypotonic or isotonic fluids. This study was prompted after we encountered a patient who developed near-fatal hyponatremic encephalopathy following a renal biopsy while receiving hypotonic fluids. The relationship between the change in serum sodium and AVP levels was evaluated prior to (T0) and at 5 h (T5) following a percutaneous renal biopsy in 60 children receiving either hypotonic (0.6% NaCl, 90 mEq/L) or isotonic fluids (0.9% NaCl, 154 mEq/L). The proportion of patients with elevated AVP levels post-procedure was similar between those receiving 0.6 or 0.9% NaCl (30 vs. 26%). Patients receiving 0.6% NaCl with elevated AVP levels experienced a fall in serum sodium of 1.9 ± 1.5 mEq/L, whereas those receiving 0.9% NaCl had a rise in serum sodium of 0.85 ± 0.34 mEq/L with no patients developing hyponatremia. There were no significant changes in serum sodium levels in patients with normal AVP concentrations post-procedure in either group. In conclusion, elevated AVP levels were common among our patients following a percutaneous renal biopsy. Isotonic fluids prevented a fall in serum sodium and hyponatremia, while hypotonic fluids did not.

The aim of this study was to compare the effect of three different intravenous (i.v.) fluid regimes on the incidence of hyponatraemia in hospitalized children ranging in age from 3 months to 12 years. Children who required the administration of i.v. maintenance fluid for at least 24 h following hospitalization were eligible for inclusion. The children were randomized to three i.v. fluid groups: Group A, 0.9% saline in 5% dextrose at the standard maintenance rate; Group B, 0.18% saline in 5% dextrose at the standard maintenance rate; Group C, 0.18% saline in 5% dextrose at two-thirds of the standard maintenance rate. The primary outcome measure was incidence of hyponatraemia (plasma sodium < 130 mEq/L). Of the 167 patients enrolled, 58, 56 and 53 patients were randomized to Group A, B and C, respectively. We observed that 14.3% (8/56) of the children administered 0.18% saline in 5% dextrose at the standard maintenance rate (Group B) developed hyponatraemia compared with 1.72% of the children in Group A and 3.8% of those in Group C. Based on these results, we conclude that the administration of 0.9% saline in 5% dextrose as i.v. maintenance fluid helps in reducing the incidence of hospital-acquired hyponatraemia among children.

Several case reports have presented various neurological complications caused by lightning. However, there was no report related to cerebral salt wasting caused by lightning injury. We described a patient with lightning strike, who was subsequently diagnosed with cerebral salt wasting.

Hypotonic saline solutions have been used for over five decades to treat children with diarrheal dehydration. However, concern has recently been raised about the potential for iatrogenic hyponatremia as a result of this therapy. We reviewed the medical records of 531 otherwise healthy children with gastroenteritis who had been admitted to the hospital for intravenous fluid therapy. We retrospectively collected data on 141 of these children who had received two serum electrolytes (one upon admission and the other 4-24 h thereafter). The remaining 390 children were excluded because their charts lacked the required data. We analyzed data in 124 of these 141 patients whose initial serum sodium (Na) level was between 130-150 mEq/l and excluded 17 patients whose admission serum sodium fell outside this range. All patients were treated with intravenous hypotonic fluids (5% dextrose in 0.2% saline, n = 4; 5% dextrose in 0.3% saline, n = 102; 5% dextrose in 0.45% saline, n = 18 patients) as maintenance fluid therapy or maintenance fluid plus deficit therapy; 100 of these children had received an initial saline bolus of 21.05 +/- 8.5 ml/kg upon admission. The serum Na level decreased by 1.7 +/- 4.3 mEq/l in the whole group. Of the 97 children with isonatremia (Na 139.5 +/- 2.7 mEq/l) on admission, 18 (18.5%) developed mild hyponatremia (Na 133.4 +/- 0.9 mEq/l, range 131-134), with a decrease in serum Na of 5.7 +/- 3.1 mEq/l, and 79 remained isonatremic (Na 138.3 +/- 2.7 mEq/l), with a decrease in serum Na of 1.8 +/- 3.4 mEq/l (p < 0.0005). There was no significant difference in type, rate, or amount of intravenous fluid or saline bolus (26.1 +/- 10.4 vs. 20.2 +/- 8.6 ml/kg, respectively) administered in these two groups. Children who became hyponatremic were older (5.8 +/- 2.7 years) than those who remained isonatremic (2.8 +/- 3.1 years) (p < 0.0005), but there was no statistical difference in gender, degree of dehydration, and severity of metabolic acidosis between the two groups. Although serum Na increased by 3.9 +/- 2.5 mEq/l in 19 patients with mild hyponatremia upon admission (Na 132.8 +/- 1.3 to 136.7 +/- 2.6 mEq/l) and 73% of these became isonatremic, hypotonic saline solutions have the potential to cause hyponatremia in children with gastroenteritis and isonatremic dehydration.

Hyponatremic hypertensive syndrome (HHS) is rare and is characterized with hypertension together with hyponatremia, hypokalemia and low plasma osmolarity and considered to be based on renal ischemia. It can rarely develop due to antiphospholipid syndrome (APS). We reported a case of 43-year-old man with unilateral renal artery stenosis due to primary APS. He presented with a hypertensive hyponatremic episode. First, he was treated with antihypertensive drugs. Further, radiological imaging showed enlargement of bilaterally adrenal glands that mimic adrenal masses. Unilateral nephrectomy and adrenalectomy were performed. Pathological examination revealed necrosis in the adrenal tissue and thrombosis in its artery. After operation, acute adrenal insufficiency developed in the patient because of hemorrhagic infarction of bilaterally adrenal glands. He improved after intravenous hydrocortisone treatment. His therapy was maintained with oral prednisolone and fludrocortisone. This patient with HHS, due to primary APS, is the first case in literature and acute adrenal insufficiency is a rare complication of APS.

Hypotonic fluids are commonly used for treating hospitalized children. However, an excess of arginine vasopressin (AVP) with impaired free water excretion is thought to contribute to the development of hyponatremia in febrile children. The aim of this two-part study was to define the clinical relationship between hyponatremia and excess AVP. In a retrospective study carried out between 2001 and 2005, we found that approximately 17% of the hospitalized patients had hyponatremia [serum sodium (Na) < 135 mEq/l] upon admission and that the ratio of patients with hyponatremia was significantly higher among febrile patients than among afebrile patients. In a subsequent prospective study, we examined 73 hospitalized patients who presented with acute febrile diseases accompanied by hyponatremia (serum Na <134 mEq/l). Almost all of these patients demonstrated excess AVP, defined as high plasma AVP levels (>1 pg/ml). There were no significant relationships between the levels of AVP and other laboratory variables, including serum sodium, serum osmolality, atrial natriuretic peptide, and brain natriuretic peptide. About 30% (22/73) of the patients fulfilled the criteria of the syndrome of inappropriate secretion of antidiuretic hormone. These findings suggest that fever and other nonosmotic stimuli lead directly to excess AVP and hyponatremia. We therefore recommend that isotonic fluids should be used for patients with prolonged fever and hyponatremia.

The available treatment options for hyponatremia secondary to SIADH are limited and not completely effective. Conivaptan is a vasopressin 1a and 2 receptor antagonist recently approved by the US Food and Drug Administration (FDA) for treating euvolemic and hypervolemic hyponatremia in adult patients. However, data on efficacy and safety of conivaptan in pediatrics are limited. We report a case of a 13-year-old boy with extensively metastasized anaplastic large-cell lymphoma. He also developed hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion (SIADH) prior to chemotherapy initiation. SIADH management in this case was complicated when fluid restriction was not safely attainable. Conivaptan played a significant role in this situation by allowing provision of a large amount of intravenous fluid prior to and during induction chemotherapy. It proved to be an important component in preventing uric acid nephropathy/tumor lysis syndrome. Conivaptan induced free-water clearance as indicated by increased urine output and decreased urine osmolality. The patient responded to conivaptan without any adverse effects.