Dehydration: Isonatremic, Hyponatremic, and Hypernatremic Recognition and Management

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.

Fluid management in hospitalized pediatric patients

The proper use of intravenous fluids has likely been responsible for saving more lives than any other group of substances. Proper use includes prescribing an appropriate electrolyte and carbohydrate solution, at a calculated rate or volume, for the right child, at the right time. Forming intravenous fluid plans for hospitalized children requires an understanding of water and electrolyte physiology in healthy children and how different pathology deviates from the norm. This review highlights fluid management in several disease types, including liver disease, diabetic ketoacidosis, syndrome of inappropriate antidiuretic hormone, diabetes insipidus, kidney disease, and intestinal failure as well as in those with nonphysiologic fluid losses. For each disease, the review discusses specific considerations, evaluations, and management strategies to consider when customizing intravenous fluid plans. Ultimately, all hospitalized children should receive an individualized fluid plan with recurrent evaluations and fluid modifications to provide optimal care.

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.

Severe Hypernatremia in a Significantly Underweight Female Child

In this study, we present the case of a 5-year-old female who presented for evaluation of dehydration with labs that revealed significant hypernatremia concerning for diabetes insipidus (DI). Further evaluation revealed that she had underlying chronic malnutrition. Her diagnostic work up for DI produced some evidence consistent with DI while other data indicated otherwise, bringing up the possibility of partial DI. She was ultimately diagnosed with sporadic vasopressin release secondary to her chronic malnutrition. This case illustrates another effect chronic malnutrition can have on pediatric patients along with the importance of a broad differential for patients with severe hypernatremia.

How to interpret symptoms, signs and investigations of dehydration in children with gastroenteritis

Dehydration is a significant cause of morbidity and mortality in children worldwide. Infants and young children are vulnerable to dehydration, and clinical assessment plays a pivotal role in their care. In addition, laboratory investigations can, in some children, be helpful when assessing the severity of dehydration and for guiding rehydration treatment. In this interpretation, we review the current literature and provide an evidence-based approach to recognising and managing dehydration in children.

Acute Infectious Gastroenteritis in Infancy and Childhood

BACKGROUND

Despite the introduction of vaccination against rotavirus, and even though it can often be treated on an outpatient basis, acute infectious gastroenteritis is nevertheless the second most common non-traumatic cause of emergency hospitaliza - tion in children aged 1 to 5 years, accounting for approximately 9% of cases (39 410 cases in 2017). The most common path - ogens are viruses (47% rotavirus, 29% norovirus, and 14% adenovirus).

METHODS

This review is based on publications retrieved by a selective search in PubMed employing the terms "acute gastro - enteritis children" AND "dehydration" OR "rehydration" OR "prevention," and by manual searching (based, for example, on reference lists and expert knowledge), with subsequent evaluation including consideration of the relevant guidelines.

RESULTS

The degree of dehydration can be judged from weight loss and other clinical findings. In 17 randomized controlled trials conducted on a total of 1811 children with mild or moderate dehydration, oral rehydration with oral rehydration solution was just as effective as intravenous rehydration with respect to weight gain, duration of diarrhea, and fluid administration, and was associated with shorter hospital stays (weighted mean difference, -1.2 days; 95% confidence interval [-2.38; -0.02]). Oral rehydration therapy failed in 4% of patients [1; 7]. In children who are vomiting or who refuse oral rehydration solution, continuous nasogastric application is just as effective as intravenous rehydration and is the treatment of first choice.

CONCLUSION

In Germany, children with mild or moderate dehydration are often hospitalized for intravenous rehydration therapy, despite the good evidence supporting ambulatory oral rehydration. Obstacles to intersectoral care, the nursing shortage, and inadequate reimbursement must all be overcome in order to reduce unnecessary hospitalizations and thereby lessen the risk of nosocomial infection.

Risk factors for hyponatremia after hypotonic fluid infusion

BACKGROUND

Hypotonic maintenance i.v. fluids (IVF) pose a higher risk of hyponatremia than isotonic maintenance IVF, but isotonic maintenance IVF can result in excess sodium (Na) load in children. This study analyzed the incidence and risk factors for hyponatremia in children given hypotonic fluids with different Na concentrations and different maintenance rates.

METHODS

We performed a retrospective analysis using medical charts of children aged 3 months-15 years. The children were normonatremic (Na ≥135 mmol/L and <145 mmol/L) before IVF, and given IVF containing 35 mmol/L Na at a 100% maintenance rate (Na 35) or fluids containing 84 mmol/L Na at a 70% maintenance rate (Na 84) for 24-48 h.

RESULTS

Of a total of 463 children, hyponatremia (Na <135 mmol/L) occurred in 46/275 children (17%) given Na 35, and 16/188 (9%) given Na 84 (P = 0.01). On multivariate logistic regression analysis, Na 35 (OR, 2.19; 95%CI: 1.04-4.62), low clinical dehydration scale (CDS) score before IVF (OR, 0.17; 95%CI: 0.06-0.49), and high body temperature 24-48 h after maintenance IVF (OR, 2.39; 95%CI: 1.79-3.18) were independent risk factors for hyponatremia.

CONCLUSIONS

Maintenance IVF with low Na concentration at a 100% maintenance rate, low CDS before IVF, and a high body temperature 24-48 h after maintenance IVF are independent risk factors for hyponatremia.

Neonatal Hypernatremic Dehydration

Hypernatremic dehydration in exclusively breast-fed neonates is associated with a free water deficit secondary to inadequate fluid intake. It is a common but underrecognized problem in the primary care setting, as the degree of dehydration can be underestimated due to fluid shifts. Neonates of primiparous mothers and those who experience greater weight loss in the first week of life are at higher risk of developing hypernatremic dehydration and most often present for care between 6 and 10 days of life. No consensus treatment guidelines exist, but most experts recommend a goal reduction rate of serum sodium levels of 0.5 mEq/L per hour with correction over 48 hours. Serum sodium level greater than 160 mEq/L is a risk factor for morbidity and mortality. Complications of hypernatremic dehydration, with seizure being most common, usually occur during improper correction. Several small studies have documented varying degrees of neurodevelopmental delay on long-term follow-up of patients admitted for hypernatremic dehydration treatment as a neonate. [Pediatr Ann. 2019;48(5):e197-e200.].

Clinical Practice Guideline: Maintenance Intravenous Fluids in Children

Maintenance intravenous fluids (IVFs) are used to provide critical supportive care for children who are acutely ill. IVFs are required if sufficient fluids cannot be provided by using enteral administration for reasons such as gastrointestinal illness, respiratory compromise, neurologic impairment, a perioperative state, or being moribund from an acute or chronic illness. Despite the common use of maintenance IVFs, there is high variability in fluid prescribing practices and a lack of guidelines for fluid composition administration and electrolyte monitoring. The administration of hypotonic IVFs has been the standard in pediatrics. Concerns have been raised that this approach results in a high incidence of hyponatremia and that isotonic IVFs could prevent the development of hyponatremia. Our goal in this guideline is to provide an evidence-based approach for choosing the tonicity of maintenance IVFs in most patients from 28 days to 18 years of age who require maintenance IVFs. This guideline applies to children in surgical (postoperative) and medical acute-care settings, including critical care and the general inpatient ward. Patients with neurosurgical disorders, congenital or acquired cardiac disease, hepatic disease, cancer, renal dysfunction, diabetes insipidus, voluminous watery diarrhea, or severe burns; neonates who are younger than 28 days old or in the NICU; and adolescents older than 18 years old are excluded. We specifically address the tonicity of maintenance IVFs in children.The Key Action Statement of the subcommittee is as follows:1A: The American Academy of Pediatrics recommends that patients 28 days to 18 years of age requiring maintenance IVFs should receive isotonic solutions with appropriate potassium chloride and dextrose because they significantly decrease the risk of developing hyponatremia (evidence quality: A; recommendation strength: strong).

Management of Diarrhoeal Dehydration in Childhood: A Review for Clinicians in Developing Countries

The survival of a child with severe volume depletion at the emergency department depends on the competency of the first responder to recognize and promptly treat hypovolemic shock. Although the basic principles on fluid and electrolytes therapy have been investigated for decades, the topic remains a challenge, as consensus on clinical management protocol is difficult to reach, and more adverse events are reported from fluid administration than for any other drug. While the old principles proposed by Holliday and Segar, and Finberg have stood the test of time, recent systematic reviews and meta-analyses have highlighted the risk of hyponatraemia, and hyponatraemic encephalopathy in some children treated with hypotonic fluids. In the midst of conflicting literature on fluid and electrolytes therapy, it would appear that isotonic fluids are best suitable for the correction of hypotonic, isonatraemic, and hypernatraemic dehydration. Although oral rehydration therapy is adequate to correct mild to moderate isonatraemic dehydration, parenteral fluid therapy is safer for the child with severe dehydration and those with changes in serum sodium. The article reviews the pathophysiology of water and sodium metabolism and, it uses the clinical case examples to illustrate the bed-side approach to the management of three different types of dehydration using a pre-mixed isotonic fluid solution (with 20 or 40 mmol/L of potassium chloride added depending on the absence or presence of hypokalemia, respectively). When 3% sodium chloride is unavailable to treat hyponatraemic encephalopathy, 0.9% sodium chloride becomes inevitable, albeit, a closer monitoring of serum sodium is required. The importance of a keen and regular clinical and laboratory monitoring of a child being rehydrated is emphasized. The article would be valuable to clinicians in less-developed countries, who must use pre-mixed fluids, and who often cannot get some suitable rehydrating solutions.

Hyponatremia and Hypotonic Intravenous Fluids Are Associated With Unfavorable Outcomes of Bronchiolitis Admissions

OBJECTIVES

Hyponatremia has been associated with unfavorable outcomes when present at admission in children with bronchiolitis. Delayed hyponatremia may be a modifiable risk factor for severe disease that is influenced by intravenous fluid (IVF) tonicity. We hypothesized that both hyponatremia and prescription of severely hypotonic IVF are associated with unfavorable outcomes, and that prescription of severely hypotonic IVF is associated with subsequent hyponatremia.

METHODS

Data were retrospectively extracted for 1557 pediatric inpatients with bronchiolitis. Any day on which a subject was prescribed IVF with sodium <70 mEq/L was termed "IVF <70." All other days on which IVF was prescribed were termed "IVF ≥70." Any blood sodium ≤135 mEq/L defined hyponatremia for that day. All other days with sodium available were labeled normonatremia. Variables were compared with Spearman correlation, Wilcoxon rank test, or χ². Significant results had P < .05.

RESULTS

Blood sodium levels correlated negatively with hospital length of stay (r = -0.477, P < .0001). On each of the first 4 days of hospitalization, significantly increased hospital length of stay was observed in patients with hyponatremia (n = 134 [25.7% of subjects with available sodium data]) versus patients with normonatremia (n = 387 [74.3%]), and in patients prescribed IVF <70 (n = 348 [46.3% of subjects prescribed IVF]) versus patients prescribed IVF ≥70 (n = 403 [53.7%]). Patients prescribed IVF <70 had increased rates of hyponatremia on the subsequent day versus patients prescribed IVF ≥70 (50.0% vs 26.9%, P < .001).

CONCLUSIONS

In children hospitalized with bronchiolitis, hyponatremia may be a modifiable risk factor for severe disease that may be mitigated by avoiding use of severely hypotonic IVF.

Use of Hypotonic Maintenance Intravenous Fluids and Hospital-Acquired Hyponatremia Remain Common in Children Admitted to a General Pediatric Ward

AIM

To evaluate maintenance intravenous fluid-prescribing practices and the incidence of hospital-acquired hyponatremia in children admitted to a general pediatric ward.

METHODS

This is a prospective observational study conducted over a 2-month period in children ages 2 months to 5 years who were admitted to a general pediatric ward and who were receiving maintenance intravenous fluids. The composition, rate, and duration of intravenous fluids were chosen at the discretion of the treating physician. Serum biochemistries were obtained at baseline and 24 h following admission. Patients who were at high risk for developing hyponatremia or hypernatremia or had underlying chronic diseases or were receiving medications associated with a disorder in sodium and water homeostasis were excluded. Intravenous fluid composition and the incidence of hyponatremia (sodium <135 mEq/L) were assessed.

RESULTS

Fifty-six children were enrolled. All received hypotonic fluids; 87.5% received 0.18% sodium chloride (NaCl) and 14.3% received 0.45% NaCl. Forty percent of patients (17/42) with a serum sodium (SNa) less than 140 mEq/L experienced a fall in SNa with 12.5% of all patients (7/56) developing hospital-acquired or aggravated hyponatremia (126-134 mEq/L) with fall in SNa between 2 and 10 mEq/L.

CONCLUSION

Administration of hypotonic fluids was a prevalent practice in children admitted to a general pediatric ward and is associated with acute hospital-acquired hyponatremia.

Point-of-Admission Serum Electrolyte Profile of Children less than Five Years Old with Dehydration due to Acute Diarrhoea

BACKGROUND/OBJECTIVE

Fluid, electrolytes and acid base disturbances are responsible for most deaths due to acute diarrhoea. The aim of this study is to describe the point-of-admission serum electrolyte profile of children with dehydration due to acute diarrhoea.

METHODS

In this cross-sectional study, the serum electrolyte levels of 185 children with dehydration due to acute diarrhoea were assessed at the point of admission at the Diarrhoea Treatment and Training Unit of the University of Benin Teaching Hospital. The age of the study population ranged from 29 days to 59 months.

RESULTS

Out of a total of 185 subjects, 30 (16.2%), 114 (61.6%), and 41 (22.2%) had severe, moderate and mild dehydration, respectively. In addition, hyponatraemic dehydration was the most common type of dehydration, accounting for 60.5% of cases. Metabolic acidosis and hypokalaemia occurred in 59.5% and 44.3% of cases, respectively. Only the serum bicarbonate level was significantly affected by degree of dehydration (p = 0.001). Age of more than 12 months and presence of vomiting were significantly associated with hyponatraemia (p = 0.005 & p = 0.02), while age of less than or equal 12 months and absence of vomiting were associated with metabolic acidosis (p = 0.04 & p = 0.03).

CONCLUSION

The degree of dehydration appears to be a good predictor of the occurrence of metabolic acidosis while age is a risk factor for hyponatraemia and metabolic acidosis.