Electrolyte disorders

Hyponatremia in babies: a 11-year single-center study

Introduction

Hyponatremia is one of the most prevalent water-electrolyte disturbances encountered in clinical practice in pediatrics and can arise from various conditions. However, there are limited reports on hyponatremia in hospitalized infants. The objective of this study was to provide an overview of the incidence, etiologies, and clinical characteristics of hyponatremia in hospitalized babies (from birth to 3 years old) at a tertiary hospital.

Method

Computer records of all hospitalized babies (from birth to 3 years old) with hyponatremia were extracted from the First Affiliated Hospital of Guangxi Medical University's clinical databases.

Results

801 patients from 39,019 hospital admissions were found to have hyponatremia and the overall prevalence of this condition was 2.05% in babies. Patients with hyponatremia due to aldosterone signaling abnormalities, neurological disorders, and liver diseases exhibited more severe outcomes than those with other etiologies.

Conclusions

Various conditions can result in hyponatremia in hospitalized babies. Aldosterone signaling abnormalities were not that uncommon and it could lead to severe hyponatremia in babies.

Fluid management in children with volume depletion

Volume depletion is a common condition and a frequent cause of hospitalization in children. Proper assessment of the patient includes a detailed history and a thorough physical examination. Biochemical tests may be useful in selected cases. Understanding the pathophysiology of fluid balance is necessary for appropriate management. A clinical dehydration scale assessing more physical findings may help to determine dehydration severity. Most dehydrated children can be treated orally; however, intravenous therapy may be indicated in patients with severe volume depletion, in those who have failed oral therapy, or in children with altered consciousness or significant metabolic abnormalities. Proper management consists of restoring circulatory volume and electrolyte balance. In this paper, we review clinical aspects, diagnosis, and management of children with volume depletion.

Tolvaptan and urea in paediatric hyponatraemia

BACKGROUND

The syndrome of inappropriate antidiuretic hormone (SIADH) is usually treated with fluid restriction. This can be challenging in patients with obligate fluid intake for nutrition or medication. Pharmaceutical treatment with tolvaptan and urea is available but minimal paediatric data are available. We review the efficacy and safety of tolvaptan and urea in paediatric patients with SIADH.

METHODS

Retrospective review of paediatric inpatients with clinical diagnosis of SIADH. Patients were identified from pharmacy records based on tolvaptan and urea prescriptions. Relevant information was extracted from patient electronic records. The main outcome measures included the number of days to sodium normalisation, the daily change in plasma sodium concentration, and the maximum increase of plasma sodium concentration in 24 h. Reported side effects were captured.

RESULTS

Thirteen patients received tolvaptan and six urea. Five patients had both agents (tolvaptan converted to urea). Tolvaptan led to plasma sodium normalisation in 10/13 (77%) within 6 days (median 2.5 days, range [1, 6]), with a median change of sodium concentration of 7 mmol/L (- 1, 14) within the first 24 h of treatment. Three patients experienced a change in plasma sodium > 10 mmol/l/day but had no apparent side effects. Urea led to sodium normalisation in 5/6 (83%) patients. The median number of days to normalisation with urea was 2 (1, 10) with a median change of plasma sodium concentration of 2 mmol/L (- 1, 6) within the first 24 h. All patients tolerated tolvaptan and/or urea without unexpected side effects.

CONCLUSIONS

Tolvaptan and urea appear to be safe and effective when fluid restriction is challenging in paediatric SIADH. A higher resolution version of the Graphical abstract is available as Supplementary information.

Temporal profile of adverse drug reactions and associated clinical factors: a prospective observational study in a neonatal intensive care unit

OBJECTIVE

Although adverse drug reactions (ADRs) are quite common in hospitalised neonates, pharmacovigilance activities in this public are still incipient. This study aims to characterise ADRs in neonates in a neonatal intensive care unit (NICU), identifying causative drugs, temporal profile and associated factors.

DESIGN

Prospective observational study.

SETTING

NICU of a public maternity hospital in Natal/Brazil.

PARTICIPANTS

All neonates admitted to the NICU for more than 24 hours and using at least one medication were followed up during the time of hospitalisation.

PRIMARY OUTCOME MEASURES

Incidence rate and risk factors for ADRs. The ADRs were detected by an active search in electronic medical records and analysis of spontaneous reports in the hospital pharmacovigilance system.

RESULTS

Six hundred neonates were included in the study, where 118 neonates had a total of 186 ADRs. The prevalence of ADRs at the NICU was 19.7% (95% CI 16.7% to 23.0%). The most common ADRs were tachycardia (30.6%), polyuria (9.1%) and hypokalaemia (8.6%). Tachycardia (peak incidence rate: 57.1 ADR/1000 neonates) and hyperthermia (19.1 ADR/1000 neonates) predominated during the first 5 days of hospitalisation. The incidence rate of polyuria and hypokalaemia increased markedly after the 20th day, with both reaching a peak of 120.0 ADR/1000 neonates. Longer hospitalisation time (OR 0.018, 95% CI 0.007 to 0.029; p<0.01) and number of prescribed drugs (OR 0.127, 95% CI 0.075 to 0.178; p<0.01) were factors associated with ADRs.

CONCLUSION

ADRs are very common in NICU, with tachycardia and hyperthermia predominant in the first week of hospitalisation and polyuria and hypokalaemia from the third week onwards.

Clinical and pathophysiological aspects of impaired water and sodium metabolism in newborns and neurological complication

This literature review covers the pathophysiological features of water and sodium exchange in newborns. The main mechanisms regulating fluid and electrolyte balance in newborns are poorly studied. The volume and composition of the extracellular fluid are provided by the functional activity of the kidneys under the control of the neuroendocrine system. The antidiuretic hormone plays the main role in the regulation of water excretion by the kidneys. The volume of intracellular fluid depends on the passive water transport with the participation of aquaporins. Lability of water and electrolyte metabolism in newborns may be accompanied by hyponatremia. For various pathological conditions in the neonatal period, certain types of hyponatremias are characteristic. Correction of hyponatremia should be carried out taking into account its pathophysiological type. Hyponatremia is a common complication associated with severe neonatal brain damage. Hyponatremia contributes to brain damage as an independent factor. The study of indicators of water and electrolyte balance in the neonatal period has an important prognostic value for early detection of damage to the central nervous system.

Serum electrolyte abnormalities in pediatric patients presenting to an emergency department with various diseases: Age-related differences

BACKGROUND

This study evaluated the prevalence and frequency of serum electrolyte abnormalities (SEAs) in children presenting to a pediatric emergency department (PED) with various diseases.

METHODS

Pediatric patients (≤18 years) with blood electrolyte panels obtained in the PED of Lin-Kou Chang Gung Memorial Hospital, Taiwan, in the 5 years from January 1, 2016, to August 31, 2021, were enrolled in this retrospective observational study. Patients were divided into three age groups: Group A, < 4 years; Group B, 4-11 years; and Group C, 12-18 years. The associations between SEAs and clinical diseases in children and age-related differences were assessed.

RESULTS

This study included 182,058 pediatric patients visiting our PED over a 5-year period. A total of 250 (0.14%) patients with SEAs were included in the analysis. The study population consisted of 127 boys and 123 girls with a median (IQR) age of 9.0 (3.2-14.1) years. Hospital admission was required in 86.4% (n = 216) of the patients, and 32.4% (n = 81) of them were admitted to the pediatric intensive care unit (PICU). The median (IQR) hospital stay and PICU stay was 6.5 (4.0-11.0) and 4.0 (3.0-8.0) days, respectively. The PICU stay was longer in Group A (p < 0.05) and shorter in group C (p < 0.05). Hyponatremia was the most common SEA in group A (46.3%, n = 31), while hypokalemia was common in groups B (54.2%, n = 52) and C (32.2%, n = 28). Gastrointestinal, renal, and endocrine diseases were common clinical conditions associated with SEAs in pediatric patients in our PED.

CONCLUSION

The detection rate of SEAs in patients in the PED was 0.14%. Hyponatremia was a common SEA in pediatric patients aged <4 years, while the most common electrolyte disorder in those >4 years old was hypokalemia. In infants and young children, SEAs were associated with a longer PICU stay.

Fluid and Electrolyte Management in the Neonate: Potassium and Phosphorus

Maintenance of electrolyte balance in the neonate is challenging in the context of illness or prematurity. Imbalances in potassium and phosphorus can occur in neonates, ranging from benign and clinically insignificant to those that can be life-threatening. An individualized approach to fluid and electrolyte management is based on the neonate's gestational age, day of life, maintenance needs, deficits, and ongoing losses. This article reviews normal and abnormal potassium and phosphorus values along with management strategies. Using a case scenario, the reader can apply concepts outlined in this article to management of critically ill neonates with electrolyte disturbances.

Vasopressin associated hyponatremia in critically ill children: A cross-sectional study

Background

The association of hyponatremia with vasopressin therapy in children is controversial. We aimed to evaluate the incidence and severity of hyponatremia associated with the administration of vasopressin in critically ill pediatric patients.

Methods

This retrospective cross-sectional study included children younger than 14 years who were admitted to the pediatric or pediatric cardiac intensive care units and received vasopressin for at least 24 h.

Results

In total, 176 critically ill pediatric patients were enrolled, with a median age of 22 days (7.3–146). The mean sodium level was notably decreased from 143.5 mEq/L ± 7.15 at the baseline to 134.3 mEq/L ± 7.7 at the 72-hour measurement after the initiation of vasopressin and varied significantly at all intervals from the baseline measurement (P < 0.001). Twenty-four hours after the discontinuation of vasopressin, more than half of the patients had hyponatremia. The highest proportion had mild hyponatremia (32.8%), followed by moderate hyponatremia (13.1%), and profound hyponatremia (7.5%). The incidence of hyponatremia was independent of gender (P = 0.94) or age group (P = 0.087). However, more than two-thirds of the moderate-profound cases and more than one-third of mild cases were observed in the neonate group (P = 0.043). The vasopressin dose did not affect the incidence (P = 0.25) or the severity of the hyponatremia (P = 0.56). Notably, all laboratory and hemodynamic parameters varied significantly at the end of therapy, compared to the baseline.

Conclusions

Continuous monitoring for hyponatremia when children are placed on vasopressin is essential to protect against more severe complications.

Fluid and Electrolyte Management in the Neonate: Sodium and Chloride

Maintenance of electrolyte balance in the neonate is a challenge in the context of illness or prematurity. Neonatal providers' approach to fluid management changes and adapts based on the newborn's age, maintenance needs, deficits, and ongoing losses. Understanding the total body water content of the fetus and newborn is foundational to management of electrolyte disturbances. This article reviews common imbalances of sodium and chloride, identifies causes of imbalances, and discusses current evidence-based treatment options.

Diagnosis and management of hypernatraemia in children

Hypernatraemia is most commonly caused by excessive loss of solute-free water or decreased fluid intake; less often, the aetiology is salt intoxication. Especially infants, young children and individuals with a lack of access to water are at risk of developing hypernatraemia. Diagnosis is based on detailed history, physical examination and basic laboratory tests. Correction of hypernatraemia must be slow to prevent cerebral oedema and irreversible brain damage. This article reviews the aetiology, differential diagnosis and management of conditions associated with paediatric hypernatraemia. Distinguishing states with water deficiency from states with salt excess is important for proper management of hypernatraemic patients.

The invention of aldosterone, how the past resurfaces in pediatric endocrinology

Sodium and water homeostasis are drastically modified at birth, in mammals, by the transition from aquatic life to terrestrial life. Accumulating evidence during the past ten years underscores the central role for the mineralocorticoid signaling pathway, in the fine regulation of this equilibrium, at this critical period of development. Interestingly, regarding evolution, while the mineralocorticoid receptor is expressed in fish, the appearance of its related ligand, aldosterone, coincides with terrestrial life, as it is first detected in lungfish and amphibian. Thus, aldosterone is likely one of the main hormones regulating the transition from an aquatic environment to an air environment. This review will focus on the different actors of the mineralocorticoid signaling pathway from aldosterone secretion in the adrenal gland, to mineralocorticoid receptor expression in the kidney, summarizing their regulation and roles throughout fetal and neonatal development, in the light of evolution.

Aldosterone signaling defect in young infants: single-center report and review

BACKGROUND

Aldosterone (Ald) is a crucial factor in maintaining electrolyte and water homeostasis. Defect in either its synthesis or function causes salt wasting (SW) manifestation. This disease group is rare, while most reported cases are sporadic. This study aimed to obtain an overview of the etiology and clinical picture of patients with the above condition and report our rare cases.

METHODS

A combination of retrospective review and case studies was conducted at the Pediatric Endocrine unit of The First Affiliated Hospital Sun Yat Sen University from September 1989 to June 2020.

RESULTS

A total of 187 patients with SW were enrolled, of which 90.4% (n = 169) were diagnosed with congenital adrenal hyperplasia (CAH). SW type 21-hydroxylase deficiency accounted for 98.8% (n = 167) of CAH diagnosis, while 1.2% (n = 2) was of lipoid CAH. Non-CAH comprised 9.6% (n = 18) of the total patients whose etiologies included SF-1 gene mutation (n = 1), X-linked adrenal hypoplasia congenita (n = 9), aldosterone synthase deficiency (ASD, n = 4), and pseudo-hypoaldosteronism type 1 (PHA1, n = 1). Etiologies were not identified in three patients. All of patients with ASD and PHA1 exhibited SW syndrome in their early neonatal period. DNA sequencing showed mutations of CYP11B2 for P1-P4 and NR3C2 for P5. P1 and P2 were sibling brothers affected by compound heterozygous mutations of c.1121G > A (p.R374Q) and c.1486delC p.(L496fs); likewise, P4 was identified with compound heterozygous mutations of c.1200 + 1G > A and c.240-1 G > T; meanwhile P3 demonstrated c.1303G > A p.(G435S) homozygous mutation in CYP11B2 gene. Lastly, P5 showed c.1768 C > T p.(R590*) heterozygous mutation in the NR3C2 gene.

CONCLUSION

Etiology of infant with aldosterone defect was mostly congenital. Renal and adrenal imaging are recommended to exclude renal causes. If clinical picture is suggestive, normal plasma Ald in early infancy cannot rule out aldosterone insufficiency.

Detection of hypokalemia disorder and its relation with hypercalcemia in blood serum using LIBS technique for patients of colorectal cancer grade I and grade II

Cancer continues to be the most dangerous disease around the world; it causes electrolyte imbalance as well as metabolic changes. There is a complicated relationship between electrolyte disorder and cancer. Cancer patients commonly pass with abnormalities in serum electrolyte levels such as hypokalemia, hyperkalemia, hyponatremia, and hypercalcemia. So, these electrolyte imbalances indicate the existence of paraneoplastic processes and help come to a more informed prognosis. Hypokalemia is defined as a serum potassium concentration below 3.5 mmol/L and it is the second common electrolyte imbalance seen in patients with malignant diseases. In this paper, the contribution of serum potassium concentration to tumor progression was studied by applying a promising and non-invasive technique called laser-induced breakdown spectroscopy (LIBS). It was found that there is a correlation between hypokalemia and the colorectal cancer problem. Also, significant serum potassium concentration differences were detected among two different stages of the same cancer and also between two groups of the same stage of a cancer held in common but one of them suffers from hypercalcemia. In addition, the optimum conditions of LIBS setup were arranged such that it will be suitable to work with serum samples on glass substrate.

Molecular and physical technologies for monitoring fluid and electrolyte imbalance: A focus on cancer population

Several clinical examinations have shown the essential impact of monitoring (de)hydration (fluid and electrolyte imbalance) in cancer patients. There are multiple risk factors associated with (de)hydration, including aging, excessive or lack of fluid consumption in sports, alcohol consumption, hot weather, diabetes insipidus, vomiting, diarrhea, cancer, radiation, chemotherapy, and use of diuretics. Fluid and electrolyte imbalance mainly involves alterations in the levels of sodium, potassium, calcium, and magnesium in extracellular fluids. Hyponatremia is a common condition among individuals with cancer (62% of cases), along with hypokalemia (40%), hypophosphatemia (32%), hypomagnesemia (17%), hypocalcemia (12%), and hypernatremia (1-5%). Lack of hydration and monitoring of hydration status can lead to severe complications, such as nausea/vomiting, diarrhea, fatigue, seizures, cell swelling or shrinking, kidney failure, shock, coma, and even death. This article aims to review the current (de)hydration (fluid and electrolyte imbalance) monitoring technologies focusing on cancer. First, we discuss the physiological and pathophysiological implications of fluid and electrolyte imbalance in cancer patients. Second, we explore the different molecular and physical monitoring methods used to measure fluid and electrolyte imbalance and the measurement challenges in diverse populations. Hydration status is assessed in various indices; plasma, sweat, tear, saliva, urine, body mass, interstitial fluid, and skin-integration techniques have been extensively investigated. No unified (de)hydration (fluid and electrolyte imbalance) monitoring technology exists for different populations (including sports, elderly, children, and cancer). Establishing novel methods and technologies to facilitate and unify measurements of hydration status represents an excellent opportunity to develop impactful new approaches for patient care.

Hyponatraemia despite isotonic maintenance fluid therapy: a time series intervention study

OBJECTIVE

To examine the prevalence of dysnatraemias among children admitted for paediatric surgery before and after a change from hypotonic to isotonic intravenous maintenance fluid therapy.

DESIGN

Retrospective consecutive time series intervention study.

SETTING

Paediatric surgery ward at the Children's Hospital in Lund, during a 7-year period, 2010-2017.

PATIENTS

All children with a blood sodium concentration measurement during the study period were included. Hypotonic maintenance fluid (40 mmol/L NaCl and 20 mmol/L KCl) was used during the first 3 years of the study (646 patients), and isotonic solution (140 mmol/L NaCl and 20 mmol/L KCl) was used during the following period (807 patients).

MAIN OUTCOME MEASURES

Primary outcomes were sodium concentration and occurrence of hyponatraemia (<135 mmol/L) or hypernatraemia (>145 mmol/L).

RESULTS

Overall, the change from hypotonic to isotonic intravenous maintenance fluid therapy was associated with a decreased prevalence of hyponatraemia from 29% to 22% (adjusted OR 0.65 (0.51-0.82)) without a significantly increased odds for hypernatraemia (from 3.4% to 4.3%, adjusted OR 1.2 (0.71-2.1)). Hyponatraemia <130 mmol/L decreased from 6.2% to 2.6%, and hyponatraemia <125 mmol/L decreased from 2.0% to 0.5%.

CONCLUSIONS

Routine use of intravenous isotonic maintenance fluids was associated with lower prevalence of hyponatraemia, although hyponatraemia still occurred in over 20% of patients. We propose that the composition and the volume of administered fluid need to be addressed.

ELBW infants receive inadvertent sodium load above the recommended intake

BACKGROUND

To determine total sodium load, including inadvertent load, during the first 2 postnatal weeks, and its influence on serum sodium, morbidity, and mortality in extremely low birth weight (ELBW, birth weight <1000 g) infants and to calculate sodium replacement models.

METHODS

Retrospective data analysis on ELBW infants with a gestational age <28 + 0/7 weeks.

RESULTS

Ninety patients with a median birth weight of 718 g and a median gestational age of 24 + 6/7 weeks were included. Median sodium intake during the first 2 postnatal weeks was 10.2 mmol/kg/day, which was significantly higher than recommended (2-5 mmol/kg/day). Sodium intake did not affect the risk for hypernatremia. Each mmol of sodium intake during the first postnatal week was associated with an increased risk of bronchopulmonary dysplasia (45%) and higher-grade intraventricular hemorrhage (31%), during the second postnatal week for necrotizing enterocolitis (19%), and during both postnatal weeks of mortality (13%). Calculations of two sodium replacement models resulted in a decrease in sodium intake during the first postnatal week of 3.2 and 4.0 mmol/kg/day, respectively.

CONCLUSIONS

Sodium load during the first 2 postnatal weeks of ELBW infants was significantly higher than recommended owing to inadvertent sodium intake and was associated with a higher risk of subsequent morbidity and mortality, although the study design does not allow conclusions on causality. Replacement of 0.9% saline with alternative carrier solutions might reduce sodium intake.

IMPACT

Sodium intake in ELBW infants during the first 2 postnatal weeks was twofold to threefold higher than recommended; this was mainly caused by inadvertent sodium components. High sodium intake is not related to severe hypernatremia but might be associated with a higher morbidity in terms of BPD, IVH, and NEC. Inadvertent sodium load can be reduced by replacing high sodium-containing carrier solutions with high levels of sodium with alternative hypotonic and/or balanced fluids, model based.

Extreme Neonatal Hypernatremia and Acute Kidney Injury Associated with Failure of Lactation

Hypoalimentation is an important cause of hypernatremic dehydration in neonates; however, extreme values of plasma sodium make it necessary to investigate the differential diagnosis. We report the case of a 20-day-old newborn who was admitted with severe hypernatremic dehydration, with plasma sodium of 213 mEq/L and oliguric acute renal failure. The patient was treated with intravenous fluids for correction of dehydration and peritoneal dialysis for adequate sodium correction. During the etiological study, a 10-fold increase in the concentration of sodium in breast milk was detected. Peritoneal dialysis was an effective therapy in the management of the extreme hypernatremia with sodium correction within the recommended rate. At the 1-year follow-up appointment, the child had normal renal function, normal for age psychomotor development, and neurological physical was unremarkable. In conclusion, we report a case of an unusual extreme hypernatremia with discussion of the underlying pathophysiology and, more importantly, the effective treatment with a mixed approach with intravenous fluids and peritoneal dialysis.

Clinical Approach to Sodium Homeostasis Disorders in Children with Pituitary-Suprasellar Tumors

Children with pituitary-suprasellar tumors are at high risk of developing sodium metabolism disorders since the tumoral mass itself or surgical and medical treatment can damage AVP release circuits. Additional risk factors are represented by the use of hypotonic fluids, the young age, total parenteral nutrition, and obstructive hydrocephalus secondary to tumor pathology. The most frequent hyponatremic disorders related to AVP in these patients are the syndrome of inappropriate ADH secretion and the cerebral/renal salt wasting syndrome, while hypernatremic conditions include central diabetes insipidus (CDI) and adipsic CDI. The main challenge in the management of these patients is to promptly distinguish the AVP release disorder at the base of the sodium imbalance and treat it correctly by avoiding rapid sodium fluctuations. These disorders can coexist or follow each other in a few hours or days; therefore, careful clinical and biochemical monitoring is necessary, especially during surgery, the use of chemotherapeutic agents, or radiotherapy. This monitoring should be performed by experienced healthcare professionals and should be multidisciplinary, including pediatric endocrinologists, neurosurgeons, and oncologists since maintaining sodium homeostasis also plays a prognostic role in terms of disease survival, therapeutic response, hospitalization rate, and mortality. In this review, we analyze the management of sodium homeostasis disorders in children with pituitary-suprasellar tumors and discuss the main challenges in the diagnosis and treatment of these conditions based on literature data and over 30 years of clinical experience at our Department of Pediatric Endocrinology.

Renoprotective Effect of Laminaria japonica Polysaccharide in Adenine-Induced Chronic Renal Failure

Chronic renal failure (CRF) is a major public health problem worldwide. In this work, we investigated the effects of a purified Laminaria japonica polysaccharide (LJP61A) on renal function using an adenine-induced CRF mice model. Results exhibited that adenine treatment caused serious renal pathological damages and elevation of serum creatinine and blood urea nitrogen of mice. However, these changes could be significantly reversed by the administration of LJP61A in a dose-dependent manner. Additionally, LJP61A could dramatically reduce weight loss, improve the urine biochemical index, and regulate the electrolyte disturbance of CRF mice. These results suggest that the renal function of adenine-induced CRF mice can be improved by LJP61A, which might be developed into a potential therapeutic agent for CRF patients.

Blood potassium and urine aldosterone after doxapram therapy for preterm infants

OBJECTIVE

We often encounter infants who developed hypokalaemia following low-dose doxapram for apnea of prematurity (AOP).

AIMS

To determine changes in blood potassium (K+) levels after doxapram administration.

STUDY DESIGN

We studied infants born before 30 weeks gestation. Doxapram (0.1-0.3 mg/kg/h) in addition to methylxanthines was used to treat AOP refractory to methylxanthines.

RESULTS

Twenty-five infants received doxapram were studied. Fifty-two percent developed hypokalemia (<3.0 mEq/L) during doxapram administration. Time after starting doxapram to nadir blood K+ (<3.0 mEq/L) level was 11 days. Blood K+ levels normalized after 5 days of stopping doxapram administration. Data at 10 days before and after and at the time of doxapram administration were, respectively: lowest blood K+ level: 3.9, 3.0, and 3.6 mEq/L; urine aldosterone: 90, 206, and 146 pg/μg creatinine. Blood pH, blood pressure and urine volume were similar.

CONCLUSIONS

Doxapram-induced hypokalemia may be due to an inappropriate increase in aldosterone levels.

Metabolic changes during brief periods of ewe–lamb separation at different ages

The present study evaluated metabolic changes in lambs during three brief periods of ewe–lamb separation, namely 1 min (T1), 10 min (T10) and 60 min (T60). The lambs were divided by age into the following three groups: 15 days (G1 = 40 lambs), 30 days (G2 = 40 lambs) and 60 days (G3 = 40 lambs). The hypothesis to be tested was that breaking the ewe–lamb bond at different ages and for these brief time periods will cause significant metabolic changes in the lambs. To this end, blood samples were taken from the three test groups 24 h before separation to establish reference values (RVs), and again at the end of the three separation times. The following blood variables were analysed for all three study groups: glucose (mg/dL), lactate (mg/dL), calcium (Ca2+, mmol/L), sodium (Na+, mmol/L), potassium (K+, mmol/L), haematocrit (HTC, %), pCO2 (mmHg), pO2 (mmHg), HCO3– (mmol/L) and pH. Results showed that the G1 lambs suffered the greatest metabolic changes for the variables pO2, pCO2, glucose, lactate, pH, HCO3–, Ca2+, Na+, K+ and HCT. With respect to time, the first 10 min of separation from the mother induced marked metabolic changes in the 15-, 30- and 60-day-old lambs, but, at 60 min, the G2 and G3 lambs tended to recover their physiological RVs, while the G1 lambs did not. These findings showed that breaking the ewe–lamb bond immediately generated metabolic changes in the lambs even though they remained in a familiar, habitual environment. They also indicated that the age of the lambs at separation was a significant factor, as the older animals tended to re-establish their RVs after the metabolic changes, likely because their physiological compensating mechanisms are more efficient, or perhaps because the intensity of attachment to the mother decreases with greater age.

Water Balance and 'Salt Wasting' in the First Year of Life: The Role of Aldosterone-Signaling Defects

In newborns and infants, dehydration and salt wasting represent a relatively common cause of admission to hospital and may result in life-threatening complications. Kidneys are responsible for electrolyte homoeostasis, but neonatal kidneys show low glomerular filtration rate and immaturity of the distal nephron, leading to reduced ability to concentrate urine. High extrarenal fluid losses often contribute to the increased occurrence of electrolyte disorders. Aldosterone is essential for sodium retention in the kidney, salivary glands, sweat glands and colon. A partial and transient aldosterone resistance is present in newborns and infants, thus reducing the capability of maintaining sodium balance in specific pathological conditions. The present review examines the mechanisms making infants more susceptible to salt wasting. Peculiar aspects of renal physiology in the first year of life and management of electrolyte disorders (i.e. sodium and potassium) are considered. Finally, inherited disorders associated with neonatal salt wasting are examined in detail. © 2016 S. Karger AG, Basel.

Pathophysiology of Hyponatremia in Children

Hyponatremia is a common electrolyte disorder in children. It is generally defined as plasma sodium of less than 135 mmol/l. Sodium homeostasis is essential for maintaining intravascular volume and is tightly linked to water balance. Plasma water volume is regulated mainly by the secretion of an antidiuretic hormone (ADH) and by the thirst mechanism. ADH is synthesized in the hypothalamus and stored in the posterior hypophysis. It binds to V2 receptors in the distal nephron and induces translocation of aquaporin water channels in the plasma membrane to retain water. There are two main types of receptors involved in the control of the body water balance-osmoreceptors and baroreceptors. Osmoreceptors reside in hypothalamus and respond to changes of extracellular fluid (ECF) osmolality. Baroreceptors are mechanoreceptors that sense blood pressure in the vessel wall. Response reflexes from baroreceptors influence sympathetic outflow, vessel tonus, and cardiac output. An increase of 1% of plasma osmolality may cause an increase in ADH levels, while the threshold of volume receptors for ADH secretion is higher. However, significant hypotension is a more potent stimulus for ADH secretion than increased osmolality. The main cause of pediatric hyponatremia is an abundance of free water. This may occur in hypovolemic children with low ECF volume, normovolemic patients with inappropriately increased ADH secretion, and also in hypervolemic individuals with decreased effective circulating volume and appropriately increased ADH levels. Proper understanding of the pathophysiology of hyponatremic states is essential for establishing the correct diagnosis and appropriate therapy.

Tolvaptan is successful in treating inappropriate antidiuretic hormone secretion in infants

AIM

Using fluid restriction to treat the syndrome of inappropriate antidiuretic hormone secretion (SIADH) in infants is potentially hazardous, as fluid intake and caloric intake are connected. Antagonists for the type 2 vasopressin receptor have demonstrated efficacy in adult patients with SIADH, but evidence in children is lacking. We reviewed our experience from two cases in the UK.

METHODS

This was a retrospective review of the clinical data on two patients diagnosed with SIADH in infancy and treated with tolvaptan, an oral vasopressin receptor antagonist.

RESULTS

Persistent hyponatraemia was noted in both patients in the first month of life and eventually led to SIADH diagnoses. Initial salt supplementation in one patient resulted in severe hypertension, treated with four antihypertensive drugs. Tolvaptan was commenced at two and four months of age, respectively, and was associated with normalisation of plasma sodium values and blood pressure without the need for antihypertensive treatment. There was transient hypernatraemia in one patient, which was normalised with a dose reduction. Tolvaptan was administered by crushing the tablet and mixing it with water.

CONCLUSION

Tolvaptan provided effective treatment for SIADH in both infants and could be administered orally.

Current views on the diagnosis and management of hypokalaemia in children

Hypokalaemia is a common electrolyte disorder in children, caused by decreased potassium intake, increased gastrointestinal and urinary losses or transcellular shift. Patients with severe hypokalaemia may suffer from symptoms such as life-threatening cardiac arrhythmias. The aim of our study was to review the aetiology of hypokalaemia, suggest a diagnostic algorithm and discuss the management of patients with various aetiologies of hypokalaemia.

CONCLUSION

Understanding the pathophysiology of hypokalaemic states, along with a detailed medical history, physical examination and specific laboratory tests are required for proper diagnosis and appropriate treatment.

Hypo and Hyper: Common Pediatric Endocrine and Metabolic Emergencies

The presentation of endocrine and metabolic emergencies represents one of the more challenging clinical scenarios faced by pediatricians and emergency providers. In this review, the authors attempt to describe some of the more common entities that a provider may see and provide a guide for the recognition and management of these difficult-to-assess and often very ill children.