[Morphological predictors of water-electrolyte disorders in patients with preventive ileostomy after rectal resection for cancer]. / Issledovanie morfologicheskikh prediktorov vodno-elektrolitnykh narushenii u patsientov so sformirovannoi preventivnoi ileostomoi pri rezektsii pryamoi kishki po povodu raka.

OBJECTIVE: To analyze morphological changes in wall of functioning and non-functioning small intestine in patients with preventive ileostomy and to determine histological predictors of water-electrolyte disorders. MATERIAL AND METHODS: We prospectively analyzed 57 patients >18 years old who underwent rectal resection with preventive ileostomy between January 2022 and November 2023. Anthropometric data included gender, age, body mass index, ECOG and ASA classes. Complications associated with large losses through ileostomy were water-electrolyte disorders, dehydration and acute renal failure with repeated hospitalization. Morphological analysis implied intraoperative full-layer biopsy of small intestine on anterior abdominal wall (ileostomy). Intraoperative biopsy of efferent and afferent loops was also carried out. Tissue samples were examined by light microscopy. We analyzed mean height of mucous membrane villi and depth of crypts, as well as their ratio. Fibrosis and swelling of submucosa were evaluated too. The results were analyzed in the SPSS Statistics 20 software. RESULTS: Mean height of intestinal villi <465 microns (p=0.028), ratio of their height to crypt depth <4.38 (p=0.034) and submucosal fibrosis (p=0.031) significantly affected malabsorption and readmission of patients. The risk of readmission was 11.5 and 5.5 times higher in univariate analysis. Multivariate analysis revealed in-hospital dehydration with resumption of infusion therapy as a predictor of readmission (p=0.046). CONCLUSION: Ileostomy is a certain stress for the patient's body. Not every patient is able for adaptation. One of the adaptation mechanisms is hypertrophy of mucous membrane villi involved in digestion. This mechanism is less pronounced in patients with repeated hospitalizations. Preoperative morphological examination of ileum mucosa may be an additional objective predictor of possible complications of preventive ileostomy.

[Application and control of intravenous fluids in German intensive care units : A national survey among critical care physicians]. / Die Applikation und Steuerung von intravenösen Flüssigkeiten auf deutschen Intensivstationen : Eine nationale Umfrage unter Intensivmediziner:innen.

BACKGROUND: The administration of intravenous fluids includes various indications, e.g., fluid replacement, nutritional therapy or as a solvent for drugs and is a common routine in the intensive care unit (ICU); however, overuse of intravenous fluids can lead to fluid overload, which can be associated with a poorer outcome in critically ill patients. OBJECTIVE: The aim of this survey was to find out the current status of the use and management of intravenous fluids as well as the interprofessional cooperation involving clinical pharmacists on German ICUs. METHODS: An online survey with 33 questions was developed. The answers of 62 participants from the Scientific Working Group on Intensive Care Medicine of the German Society for Anesthesiology and Intensive Care Medicine were evaluated. RESULTS: Fluid overload occurs "frequently" in 62.9% (39/62) and "very frequently" in 9.7% (6/62) of the ICUs of respondents. An established standard for an infusion management system is unknown to 71.0% (44/62) of participants and 45.2% of the respondents stated that they did not have a patient data management system. In addition, the participants indicated how they define fluid overload. This was defined by the presence of edema by 50.9% (28/55) and by positive fluid balance by 30.9% (17/55). According to the participants septic patients (38/60; 63.3%) and cardiological/cardiac surgical patients (26/60; 43.3%) are most susceptible to the occurrence of fluid overload. Interprofessional collaboration among intensive care physicians, critical care nurses, and clinical pharmacists to optimize fluid therapy was described as "relevant" by 38.7% (24/62) and "very relevant" by 45.2% (28/62). Participants with clinical pharmacists on the wards (24/62; 38.7%) answered this question more often as "very relevant" with 62.5% (15/24). CONCLUSION: Fluid overload is a frequent and relevant problem in German intensive care units. Yet there are few established standards in this area. There is also a lack of validated diagnostic parameters and a clear definition of fluid overload. These are required to ensure appropriate and effective treatment that is tailored to the patient and adapted to the respective situation. Intravenous fluids should be considered as drugs that may exert side effects or can be overdosed with severe adverse consequences for the patients. One approach to optimize fluid therapy could be achieved by a fluid stewardship corresponding to comparable established procedures of the antibiotic stewardship. In particular, fluid stewardship will contribute to drug safety of intravenous fluids profiting from joined expertise in a setting of interprofessional collaboration. An important principle of fluid stewardship is to consider intravenous fluids in the same way as medication in terms of their importance. Furthermore, more in-depth studies are needed to investigate the effects of interprofessional fluid stewardship in a prospective and controlled manner.

Choosing fluids to reduce the risks of acute electrolyte disturbances in children after a kidney transplant.

Intravenous (i.v.) fluid therapy is critically important in pediatric kidney transplantation. Because of the high volumes given perioperatively, transplant recipients can develop significant electrolyte abnormalities depending on the types of fluids used. Current practices in pediatric transplantation aim to balance risks of hyponatremia from traditionally used hypotonic fluids, such as 0.45% sodium chloride, against hyperchloremia and acidosis associated with isotonic 0.9% sodium chloride. Using the balanced solution Plasma-Lyte 148 as an alternative might mitigate these risks.

Early repeat hospitalization for fluid overload in individuals with cardiovascular disease and risks: a retrospective cohort study.

AIMS: Fluid overload is a common manifestation of cardiovascular and kidney disease and a leading cause of hospitalizations. To identify patients at risk of recurrent severe fluid overload, we evaluated the incidence and risk factors associated with early repeat hospitalization for fluid overload among individuals with cardiovascular disease and risks. METHODS: Single-center retrospective cohort study of 3423 consecutive adults with an index hospitalization for fluid overload between January 2015 and December 2017 and had cardiovascular risks (older age, diabetes mellitus, hypertension, dyslipidemia, kidney disease, known cardiovascular disease), but excluded if lost to follow-up or eGFR < 15 ml/min/1.73 m2. The outcome was early repeat hospitalization for fluid overload within 30 days of discharge. RESULTS: The mean age was 73.9 ± 11.6 years and eGFR was 54.1 ± 24.6 ml/min/1.73 m2 at index hospitalization. Early repeat hospitalization for fluid overload occurred in 291 patients (8.5%). After adjusting for demographics, comorbidities, clinical parameters during index hospitalization and medications at discharge, cardiovascular disease (adjusted odds ratio, OR 1.66, 95% CI 1.27-2.17), prior hospitalization for fluid overload within 3 months (OR 2.52, 95% CI 1.17-5.44), prior hospitalization for any cause in within 6 months (OR 1.33, 95% CI 1.02-1.73) and intravenous furosemide use (OR 1.58, 95% CI 1.10-2.28) were associated with early repeat hospitalization for fluid overload. Higher systolic BP on admission (OR 0.992, 95% 0.986-0.998) and diuretic at discharge (OR 0.50, 95% CI 0.26-0.98) reduced early hospitalization for fluid overload. CONCLUSION: Patients at-risk of early repeat hospitalization for fluid overload may be identified using these risk factors for targeted interventions.

Peritoneal catheters in neonates undergoing complex cardiac surgery: a multi-centre descriptive study.

BACKGROUND: The use of peritoneal catheters for prophylactic dialysis or drainage to prevent fluid overload after neonatal cardiac surgery is common in some centres; however, the multi-centre variability and details of peritoneal catheter use are not well described. METHODS: Twenty-two-centre NEonatal and Pediatric Heart Renal Outcomes Network (NEPHRON) study to describe multi-centre peritoneal catheter use after STAT category 3-5 neonatal cardiac surgery using cardiopulmonary bypass. Patient characteristics and acute kidney injury/fluid outcomes for six post-operative days are described among three cohorts: peritoneal catheter with dialysis, peritoneal catheter with passive drainage, and no peritoneal catheter. RESULTS: Of 1490 neonates, 471 (32%) had an intraoperative peritoneal catheter placed; 177 (12%) received prophylactic dialysis and 294 (20%) received passive drainage. Sixteen (73%) centres used peritoneal catheter at some frequency, including six centres in >50% of neonates. Four centres utilised prophylactic peritoneal dialysis. Time to post-operative dialysis initiation was 3 hours [1, 5] with the duration of 56 hours [37, 90]; passive drainage cohort drained for 92 hours [64, 163]. Peritoneal catheter were more common among patients receiving pre-operative mechanical ventilation, single ventricle physiology, and higher complexity surgery. There was no association with adverse events. Serum creatinine and daily fluid balance were not clinically different on any post-operative day. Mortality was similar. CONCLUSIONS: In neonates undergoing complex cardiac surgery, peritoneal catheter use is not rare, with substantial variability among centres. Peritoneal catheters are used more commonly with higher surgical complexity. Adverse event rates, including mortality, are not different with peritoneal catheter use. Fluid overload and creatinine-based acute kidney injury rates are not different in peritoneal catheter cohorts.

Neonatal Chylothorax and Early Fluid Overload After Cardiac Surgery: Retrospective Analysis of the Neonatal and Pediatric Heart and Renal Outcomes Network Registry (2015-2018).

OBJECTIVES: To evaluate the association between postoperative cumulative fluid balance (FB) and development of chylothorax in neonates after cardiac surgery. DESIGN: Multicenter, retrospective cohort identified within the Neonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) Registry. SETTING: Twenty-two hospitals were involved with NEPHRON, from September 2015 to January 2018. PATIENTS: Neonates (< 30 d old) undergoing index cardiac operation with or without cardiopulmonary bypass (CPB) entered into the NEPHRON Registry. Postoperative chylothorax was defined in the Pediatric Cardiac Critical Care Consortium as lymphatic fluid in the pleural space secondary to a leak from the thoracic duct or its branches. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 2240 NEPHRON patients, 4% ( n = 89) were treated for chylothorax during postoperative day (POD) 2-21. Median (interquartile range [IQR]) time to diagnosis was 8 (IQR 6, 12) days. Of patients treated for chylothorax, 81 of 89 (91%) had CPB and 68 of 89 (76%) had Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery Congenital Heart Surgery 4-5 operations. On bivariate analysis, chylothorax patients had higher POD 1 FB (3.2 vs. 1.1%, p = 0.014), higher cumulative POD 2 FB (1.5 vs. -1.5%, p < 0.001), achieved negative daily FB by POD 1 less often (69% vs. 79%, p = 0.039), and had lower POD 1 urine output (1.9 vs. 3. 2 mL/kg/day, p ≤ 0.001) than those without chylothorax. We failed to identify an association between presence or absence of chylothorax and peak FB (5.2 vs. 4.9%, p = 0.9). Multivariable analysis shows that higher cumulative FB on POD 2 was associated with greater odds (odds ratio [OR], 95% CI) of chylothorax development (OR 1.5 [95% CI, 1.1-2.2]). Further multivariable analysis shows that chylothorax was independently associated with greater odds of longer durations of mechanical ventilation (OR 5.5 [95% CI, 3.7-8.0]), respiratory support (OR 4.3 [95% CI, 2.9-6.2]), use of inotropic support (OR 2.9 [95% CI, 2.0-4.3]), and longer hospital length of stay (OR 3.7 [95% CI, 2.5-5.4]). CONCLUSIONS: Chylothorax after neonatal cardiac surgery for congenital heart disease (CHD) is independently associated with greater odds of longer duration of cardiorespiratory support and hospitalization. Higher early (POD 2) cumulative FB is associated with greater odds of chylothorax. Contemporary, prospective studies are needed to assess whether early fluid mitigation strategies decrease postoperative chylothorax development.

Continuous renal replacement therapy in neonates and children: what does the pediatrician need to know? An overview from the Critical Care Nephrology Section of the European Society of Paediatric and Neonatal Intensive Care (ESPNIC).

Continuous renal replacement therapy (CRRT) is the preferred method for renal support in critically ill and hemodynamically unstable children in the pediatric intensive care unit (PICU) as it allows for gentle removal of fluids and solutes. The most frequent indications for CRRT include acute kidney injury (AKI) and fluid overload (FO) as well as non-renal indications such as removal of toxic metabolites in acute liver failure, inborn errors of metabolism, and intoxications and removal of inflammatory mediators in sepsis. AKI and/or FO are common in critically ill children and their presence is associated with worse outcomes. Therefore, early recognition of AKI and FO is important and timely transfer of patients who might require CRRT to a center with institutional expertise should be considered. Although CRRT has been increasingly used in the critical care setting, due to the lack of standardized recommendations, wide practice variations exist regarding the main aspects of CRRT application in critically ill children.     Conclusion: In this review, from the Critical Care Nephrology section of the European Society of Paediatric and Neonatal Intensive Care (ESPNIC), we summarize the key aspects of CRRT delivery and highlight the importance of adequate follow up among AKI survivors which might be of relevance for the general pediatric community. What is Known: • CRRT is the preferred method of renal support in critically ill and hemodynamically unstable children in the PICU as it allows for gentle removal of fluids and solutes. • Although CRRT has become an important and integral part of modern pediatric critical care, wide practice variations exist in all aspects of CRRT. What is New: • Given the lack of literature on guidance for a general pediatrician on when to refer a child for CRRT, we recommend timely transfer to a center with institutional expertise in CRRT, as both worsening AKI and FO have been associated with increased mortality. • Adequate follow-up of PICU patients with AKI and CRRT is highlighted as recent findings demonstrate that these children are at increased risk for adverse long-term outcomes.

The effect of dehydration, hyperchloremia and volume of fluid resuscitation on acute kidney injury in children admitted to hospital with diabetic ketoacidosis.

BACKGROUND: Acute kidney injury (AKI) is a recognized comorbidity in pediatric diabetic ketoacidosis (DKA), although the exact etiology is unclear. The unique physiology of DKA makes dehydration assessments challenging, and these patients potentially receive excessive amounts of intravenous fluids (IVF). We hypothesized that dehydration is over-estimated in pediatric DKA, leading to over-administration of IVF and hyperchloremia that worsens AKI. METHODS: Retrospective cohort of all DKA inpatients at a tertiary pediatric hospital from 2014 to 2019. A total of 145 children were included; reasons for exclusion were pre-existing kidney disease or incomplete medical records. AKI was determined by change in creatinine during admission, and comparison to a calculated baseline value. Linear regression multivariable analysis was used to identify factors associated with AKI. True dehydration was calculated from patients' change in weight, as previously validated. Fluid over-resuscitation was defined as total fluids given above the true dehydration. RESULTS: A total of 19% of patients met KDIGO serum creatinine criteria for AKI on admission. Only 2% had AKI on hospital discharge. True dehydration and high serum urea levels were associated with high serum creatinine levels on admission (p = 0.042; p < 0.001, respectively). Fluid over-resuscitation and hyperchloremia were associated with delayed kidney recovery (p < 0.001). Severity of initial AKI was associated with cerebral edema (p = 0.018). CONCLUSIONS: Dehydration was associated with initial AKI in children with DKA. Persistent AKI and delay to recovery was associated with hyperchloremia and over-resuscitation with IVF, potentially modifiable clinical variables for earlier AKI recovery and reduction in long-term morbidity. This highlights the need to re-address fluid protocols in pediatric DKA.

Fluid assessment, fluid balance, and fluid overload in sick children: a report from the Pediatric Acute Disease Quality Initiative (ADQI) conference.

BACKGROUND: The impact of disorders of fluid balance, including the pathologic state of fluid overload in sick children has become increasingly apparent. With this understanding, there has been a shift from application of absolute thresholds of fluid accumulation to an appreciation of the intricacies of fluid balance, including the impact of timing, trajectory, and disease pathophysiology. METHODS: The 26th Acute Disease Quality Initiative was the first to be exclusively dedicated to pediatric and neonatal acute kidney injury (pADQI). As part of the consensus panel, a multidisciplinary working group dedicated to fluid balance, fluid accumulation, and fluid overload was created. Through a search, review, and appraisal of the literature, summative consensus statements, along with identification of knowledge gaps and recommendations for clinical practice and research were developed. CONCLUSIONS: The 26th pADQI conference proposed harmonized terminology for fluid balance and for describing a pathologic state of fluid overload for clinical practice and research. Recommendations include that the terms daily fluid balance, cumulative fluid balance, and percent cumulative fluid balance be utilized to describe the fluid status of sick children. The term fluid overload is to be preserved for describing a pathologic state of positive fluid balance associated with adverse events. Several recommendations for research were proposed including focused validation of the definition of fluid balance, fluid overload, and proposed methodologic approaches and endpoints for clinical trials.

A pragmatic, open-label, randomized controlled trial of Plasma-Lyte-148 versus standard intravenous fluids in children receiving kidney transplants (PLUTO).

Acute electrolyte and acid-base imbalance is experienced by many children following kidney transplant. This is partly because doctors give very large volumes of artificial fluids to keep the new kidney working. When severe, fluid imbalance can lead to seizures, cerebral edema and death. In this pragmatic, open-label, randomized controlled trial, we randomly assigned (1:1) pediatric kidney transplant recipients to Plasma-Lyte-148 or standard of care perioperative intravenous fluids (predominantly 0.45% sodium chloride and 0.9% sodium chloride solutions). We then compared clinically significant electrolyte and acid-base abnormalities in the first 72 hours post-transplant. The primary outcome, acute hyponatremia, was experienced by 53% of 68 participants in the Plasma-Lyte-148 group and 58% of 69 participants in the standard fluids group (odds ratio 0·77 (0·34 - 1·75)). Five of 16 secondary outcomes differed with Plasma-Lyte-148: hypernatremia was significantly more frequent (odds ratio 3·5 (1·1 - 10·8)), significantly fewer changes to fluid prescriptions were made (rate ratio 0·52 (0·40-0·67)), and significantly fewer participants experienced hyperchloremia (odds ratio 0·17 (0·07 - 0·40)), acidosis (odds ratio 0·09 (0·04 - 0·22)) and hypomagnesemia (odds ratio 0·21 (0·08 - 0·50)). No other secondary outcomes differed between groups. Serious adverse events were reported in 9% of participants randomized to Plasma-Lyte-148 and 7% of participants randomized to standard fluids. Thus, perioperative Plasma-Lyte-148 did not change the proportion of children who experienced acute hyponatremia compared to standard fluids. However fewer fluid prescription changes were made with Plasma-Lyte-148, while hyperchloremia and acidosis were less common.

Reporte de caso: síndrome de absorción intravascular en histeroscopia, intoxicación por glicina / Case report: Intravascular absorption syndrome in hysteroscopy, glycine intoxication

El síndrome de absorción intravascular en histeroscopia se origina por la rápida absorción vascular de soluciones isotónicas e hipotónicas utilizadas en irrigación intrauterina, ocasionando hipervolemia y dilución de electrolitos, especialmente hiponatremia. Cuando este síndrome es debido a intoxicación por glicina al 1,5% causa acidosis severa y neurotoxicidad. La incidencia de este síndrome es baja pero puede aumentar por factores como: falta de control de altura de bolsas de irrigación, ausencia de equilibrio de fluidos de soluciones de irrigación, tejidos altamente vascularizados como miomas uterinos y uso de sistema de electrocirugía monopolar. Se reporta el caso de una paciente con miomas uterinos, programada para resección mediante histeroscopia que cursa con síndrome de absorción intravascular por glicina, el temprano diagnóstico y rápido tratamiento intraoperatorio y postoperatorio permitió una evolución favorable. El manejo se basó en el uso de diuréticos, restricción de fluidos y soluciones hipertónicas de sodio.

Intravascular absorption syndrome in hysteroscopy is caused by rapid vascular absorption of isotonic and hypotonic solutions used in intrauterine irrigation, causing hypervolemia and electrolyte dilution, especially hyponatremia. When this syndrome is due to 1.5% glycine toxicity, it causes severe acidosis and neurotoxicity. The incidence of this syndrome is low but may increase due to factors such as: lack of control of the height of irrigation bags, lack of fluid balance in irrigation solutions, highly vascularized tissues such as uterine myomas and use of a monopolar electrosurgery system. The case of a patient with uterine myomas, scheduled for resection by hysteroscopy, who presents with intravascular glycine absorption syndrome, is reported. Early diagnosis and rapid intraoperative and postoperative treatment allowed a favorable evolution. Management was based on the use of diuretics, fluid restriction, and hypertonic sodium solutions.

[Hyponatremia and Electrolyte Disorders in Cancer Patients].

Onconephrology is a rising and rapidly expanding field of medicine in which nephrology and oncology meet each other. Besides multidisciplinary meetings, oncologists and nephrologists often discuss on timing of the treatment, dosage, and side effects management. Cancer patients often encounter different electrolyte disorders. They are mostly secondary to the tumor itself or consequences of its treatment. In the last years, the great efforts to find new therapies like targeted, immune, and cell-based led us to many new side effects. Hyponatremia, hypokalemia, hyperkalemia, hypercalcemia, and hypomagnesemia are among the most common electrolyte disorders. Data have shown a worse prognosis in patients with electrolytic imbalances. Additionally, they cause a delay in chemotherapy or even an interruption. It is important to diagnose promptly these complications and treat them. In this review, we provide a special focus on hyponatremia and its treatment as the most common electrolytes disorder in cancer patients, but also on newly described cases of hypo- and hyperkalemia and metabolic acidosis.

Refeeding Syndrome in Pediatric Age, An Unknown Disease: A Narrative Review.

Refeeding syndrome (RS) is characterized by electrolyte imbalances that can occur in malnourished and abruptly refed patients. Typical features of RS are hypophosphatemia, hypokalemia, hypomagnesemia, and thiamine deficiency. It is a potentially life-threatening condition that can affect both adults and children, although there is scarce evidence in the pediatric literature. The sudden increase in food intake causes a shift in the body's metabolism and electrolyte balance, leading to symptoms such as weakness, seizures, and even heart failure. A proper management with progressive increase in nutrients is essential to prevent the onset of this condition and ensure the best possible outcomes. Moreover, an estimated incidence of up to 7.4% has been observed in pediatric intensive care unit patients receiving nutritional support, alone or as an adjunct. To prevent RS, it is important to carefully monitor feeding resumption, particularly in severely malnourished individuals. A proper strategy should start with small amounts of low-calorie fluids and gradually increasing the calorie content and amount of food over several days. Close monitoring of electrolyte levels is critical and prophylactic use of dietary supplements such as thiamine may be required to correct any imbalances that may occur. In this narrative review, we aim to provide a comprehensive understanding of RS in pediatric clinical practice and provide a possible management algorithm.

Nonresuscitation Fluid Accumulation and Outcomes After Pediatric Cardiac Surgery: Single-Center Retrospective Cohort Study.

OBJECTIVES: Postoperative patients after congenital cardiac surgery are at high risk of fluid overload (FO), which is known to be associated with poor outcomes. "Fluid creep," or nonresuscitation IV fluid in excess of maintenance requirement, is recognized as a modifiable factor associated with FO in the general PICU population, but has not been studied in congenital cardiac surgery patients. Our objective was to characterize fluid administration after congenital cardiac surgery, quantify fluid creep, and the association between fluid creep, FO, and outcome. DESIGN: Retrospective, observational cohort study. SETTING: Single-center urban mixed-medical and cardiac PICU. PATIENTS: Patients admitted to the PICU after cardiac surgery between January 2010 and December 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There were 1,459 postoperative encounters with 1,224 unique patients. Total fluid intake was greater than maintenance requirements on 3,103 of 4,661 patient days (67%), with fluid creep present on 2,624 patient days (56%). Total nonresuscitation intake was higher in patients with FO (defined as cumulative fluid balance 10% above body weight) versus those without. Fluid creep was higher among patients with FO than those without for each of the first 5 days postoperatively. Each 10 mL/kg of fluid creep in the first 24 hours postoperatively was associated with 26% greater odds of developing FO (odds ratio [OR] 1.26; 95% CI, 1.17-1.35) and 17% greater odds of mortality (OR 1.17; 95% CI, 1.05-1.30) after adjusting for risk of mortality based on surgical procedure, age, and day 1 resuscitation volume. Increasing fluid creep in the first 24 hours postoperatively was associated with increased postoperative duration of mechanical ventilation and PICU length of stay. CONCLUSIONS: Fluid creep is present on most postoperative days for pediatric congenital cardiac surgery patients, and fluid creep is associated with higher-risk procedures. Fluid creep early in the postoperative PICU stay is associated with greater odds of FO, mortality, length of mechanical ventilation, and PICU length of stay. Fluid creep may be under-recognized in this population and thus present a modifiable target for intervention.

[Hyponatremia : Etiology, diagnosis and acute therapy]. / Hyponatriämie : Ätiologie, Diagnostik und Akuttherapie.

Hyponatremia is one of the most common electrolyte disorders in emergency departments and hospitalized patients. Serum sodium concentration is controlled by osmoregulation and volume regulation. Both pathways are regulated via the release of antidiuretic hormone (ADH). Syndrome of inappropriate release of ADH (SIADH) may be caused by neoplasms or pneumonia but may also be triggered by drug use or drug abuse. Excessive fluid intake may also result in a decrease in serum sodium concentration. Rapid alteration in serum sodium concentration leads to cell swelling or cell shrinkage, which primarily causes neurological symptoms. The dynamics of development of hyponatremia and its duration are crucial. In addition to blood testing, a clinical examination and urine analysis are essential in the differential diagnosis of hyponatremia.

Hypokalemia/Hyperkalemia and Hyponatremia/Hypernatremia.

Electrolyte disorders are very common in the pediatric population. Derangements in serum sodium and potassium concentrations are among the most frequently seen given the risk factors and comorbidities unique to children. Pediatricians, in both outpatient and inpatient settings, should be comfortable with the evaluation and initial treatment of disturbances in these electrolyte concentrations. However, to evaluate and treat a child with abnormal serum concentrations of sodium or potassium, it is critical to understand the regulatory physiology that governs osmotic homeostasis and potassium regulation in the body. Comprehension of these basic physiologic processes will allow the provider to uncover the underlying pathology of these electrolyte disturbances and devise an appropriate and safe treatment plan.