Pretreatment of enteral nutrition with sodium polystyrene sulfonate: effective, but beware the high prevalence of electrolyte derangements in clinical practice

Case report: Early molecular confirmation and sodium polystyrene sulfonate management of systemic pseudohypoaldosteronism type I

Introduction

Type 1 pseudohypoaldosteronism (PHA) consists of resistance to aldosterone. Neonatal presentation is characterized by salt wasting, hyperkalemia, and metabolic acidosis with high risk of mortality. Type 1 PHA can be autosomal dominant (renal type 1) or autosomal recessive (systemic type 1). Renal PHA type 1 can be feasibly managed with salt supplementation; however, systemic PHA type 1 tends to have more severe electrolyte imbalance and can be more refractory to treatment.

Case Presentation

We present a case of a 3-year-old girl with systemic PHA type 1, diagnosed and confirmed molecularly in infancy, who has been successfully managed with sodium polystyrene sulfonate decanted into feeds along with sodium supplementation. On day 5 of life, a full-term female infant presented to the ED for 2 days of non-bloody, non-bilious emesis, along with hypothermia to 94°F. Laboratory results were notable for hyponatremia (Na) of 127, hyperkalemia (K) of 7.9, and acidosis with bicarbonate level of 11.2. Genetic testing ordered within a week of life confirmed PHA type 1 with a homozygous pathogenic frameshift variant in SCNN1A c.575delA (p.Arg192GlyfsX57). Sodium polystyrene sulfonate and feeds were decanted until the age of 16 months, and she was also continued on NaCl supplementation. She was gradually transitioned to directly administered sodium polystyrene sulfonate without any electrolyte issues. She has overall done well after gastrostomy-tube (G-tube) placement without severe hyperkalemia even with several hospitalizations for gastrointestinal or respiratory illnesses.

Discussion/Conclusion

A treatment approach to systemic PHA and sodium polystyrene sulfonate administration in neonates and infants is described.

Nutrition for critically ill children and neonates requiring dialysis: Application of clinical practice recommendations

Approximately 30% of all children and neonates admitted to the intensive care unit (ICU) experience acute kidney injury (AKI). Children with AKI are largely poorly fed and experience high rates of malnutrition. Nutrition prescription and provision are exceptionally challenging for critically ill neonates, infants, and children with AKI given the dynamic nature of AKI and its respective treatment modalities. Managing the nutrition prescription of critically ill neonates, infants, and children with AKI requires nutrition support clinicians to have a high-level understanding of the various treatment modalities for AKI, which can affect the patient's protein, fluid, electrolyte, and mineral needs. Accurate and timely nutrition assessment in critically ill neonates and children with AKI can be flawed owing to difficulty obtaining accurate anthropometric parameters. Recently, the Pediatric Renal Nutrition Taskforce introduced clinical practice recommendations for the nutrition management of children with AKI. In this review, we will discuss the practical implications of these recent guidelines and work to bridge the knowledge and practice gaps for pediatric and neonatal nutrition support clinicians providing nutrition therapy for patients with AKI in the ICU. We also appraise special nutrition-related considerations for neonates with AKI given newer available renal replacement treatment modalities.

Nutritional management of the infant with chronic kidney disease stages 2-5 and on dialysis

The nutritional management of children with chronic kidney disease (CKD) is of prime importance in meeting the challenge of maintaining normal growth and development in this population. The objective of this review is to integrate the Pediatric Renal Nutrition Taskforce clinical practice recommendations for children with CKD stages 2-5 and on dialysis, as they relate to the infant from full term birth up to 1 year of age, for healthcare professionals, including dietitians, physicians, and nurses. It addresses nutritional assessment, energy and protein requirements, delivery of the nutritional prescription, and necessary dietary modifications in the case of abnormal serum levels of calcium, phosphate, and potassium. We focus on the particular nutritional needs of infants with CKD for whom dietary recommendations for energy and protein, based on body weight, are higher compared with children over 1 year of age in order to support both linear and brain growth, which are normally maximal in the first 6 months of life. Attention to nutrition during infancy is important given that growth is predominantly nutrition dependent in the infantile phase and the growth of infants is acutely impaired by disruption to their nutritional intake, particularly during the first 6 months. Inadequate nutritional intake can result in the failure to achieve full adult height potential and an increased risk for abnormal neurodevelopment. We strongly suggest that physicians work closely with pediatric renal dietitians to ensure that the infant with CKD receives the best possible nutritional management to optimize their growth and development.

An electrolyte flip flop - a patient with chronic hyperkalemic acidosis presenting with severe hypokalemic alkalosis

A 76-year-old man was evaluated in our emergency department (ED) for right toe swelling and pain. His initial ED workup revealed volume overload, uncontrolled hypertension, slow atrial fibrillation, refractory hypokalemia, mixed metabolic alkalosis and respiratory acidosis, with a normal plasma pH, and hypernatremia. His medical chart revealed long standing hyperkalemia and metabolic acidosis, related to his diabetic kidney disease. We hypothesized that a short course of daily SPS ingestion (Sodium Polystyrene Sulfonate, "Kayexalate") was the sole etiology for the compound electrolyte abnormalities and the electrolyte "flip flop". SPS ingestion can cause hypokalemia by excessive potassium binding in the gut. SPS exchanging potassium for sodium caused excessive sodium retention leading to hypernatremia, hypertension and volume overload. Volume overload worsened his chronic obstructive sleep apnea and yielded respiratory acidosis. Finally hypokalemia by itself was the main trigger for generation and maintenance of metabolic alkalosis. Urinary electrolytes, and renin and aldosterone levels taken at the ED ruled out primary aldosteronism and renal potassium and hydrogen loss. The patient's potassium was replenished by both PO and IV routes. He was treated for his volume overload and hypertension with furosemide. Spironolactone and amiloride, potassium sparing diuretics, were cautiously given only during his hypokalemic phase. His plasma sodium and potassium levels, blood pressure and volume status gradually improved. "Kayexalate" effect should be suspected in a patient presenting with unexplained hypokalemia and alkalosis, accompanied by volume overload rather than volume depletion, developing shortly after SPS ingestion. ED doctors should specifically ask CKD or ESRD patients on SPS, as it otherwise can skip the medication reconciliation process.

Pediatric Chronic Kidney Disease

Chronic kidney disease (CKD) in children has a significant impact on morbidity, mortality, and quality of life. The degree of renal dysfunction should be calculated using pediatric-specific formulas and the degree of CKD staged; this allows for appropriate dosing of medications based on renal function and monitoring for progression and comorbid conditions including metabolic acidosis, bone disease, anemia, cardiovascular complications, malnutrition and electrolyte abnormalities, growth failure, and psychosocial issues. Treatment strategies include treating the underlying disease and using general renal protective measures. Effective management of these complex issues requires a specialized multidisciplinary team approach.

The dietary management of potassium in children with CKD stages 2-5 and on dialysis-clinical practice recommendations from the Pediatric Renal Nutrition Taskforce

Dyskalemias are often seen in children with chronic kidney disease (CKD). While hyperkalemia is common, with an increasing prevalence as glomerular filtration rate declines, hypokalemia may also occur, particularly in children with renal tubular disorders and those on intensive dialysis regimens. Dietary assessment and adjustment of potassium intake is critically important in children with CKD as hyperkalemia can be life-threatening. Manipulation of dietary potassium can be challenging as it may affect the intake of other nutrients and reduce palatability. The Pediatric Renal Nutrition Taskforce (PRNT), an international team of pediatric renal dietitians and pediatric nephrologists, has developed clinical practice recommendations (CPRs) for the dietary management of potassium in children with CKD stages 2-5 and on dialysis (CKD2-5D). We describe the assessment of dietary potassium intake, requirements for potassium in healthy children, and the dietary management of hypo- and hyperkalemia in children with CKD2-5D. Common potassium containing foods are described and approaches to adjusting potassium intake that can be incorporated into everyday practice discussed. Given the poor quality of evidence available, a Delphi survey was conducted to seek consensus from international experts. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs, based on the clinical judgment of the treating physician and dietitian. These CPRs will be regularly audited and updated by the PRNT.

[Case report of an infant hyperkalemia: Suggestion of a hospital procedure for the milk pretreatment with sodium polystyrene sulfonate resin]

Sodium polystyrene sulfonate (SPS) is used to reduce intestinal potassium absorption in hyperkalemia during conservative management of chronic renal failure in infants. Milk can be pretreated by SPS to reduce the risk of enteropathy associated with oral or rectal administration. We report the case of an infant for whom this pre-treatment has been implemented. The objective of this work was to define the hospital procedure for the pre-treatment of milk by the SPS. This pre-treatment involves both a drug and infant milk. Each product has its own regulation and their processes do not normally cross each other. The roles of each contributor were therefore defined: prescription of pre-treated milk (dose of SPS and volume of milk) by the physician, dispensing of SPS by the pharmacist, delivery of milk by the milk kitchen staff, pre-treatment by a nurse and administration by a nursing auxiliary. The preparation of the bottles is as follows: placing approximately 1g of SPS per 100mL of milk in contact, stirring, resting in the refrigerator for one hour, taking the supernatant to be administered. In the reported case, serum potassium levels were reduced from 5.57mmol/L before treatment to 4.53mmol/L after treatment, in line with the 20% decrease found in the literature. This method of administration is beneficial in terms of tolerance and acceptability. The preparation is simple and allows going back home under treatment.

Treatment of infant formula with patiromer dose dependently decreases potassium concentration

BACKGROUND

Hyperkalemia is a potentially life-threatening complication of chronic kidney disease (CKD). Dietary potassium restriction is challenging in infants despite low-potassium formulas. Decreasing potassium in formula using patiromer, a new calcium-based cation exchange polymer may be one option to accomplish this; however, data confirming efficacy is lacking.

METHODS

Varying doses of patiromer were added to prepared Similac Advance and Similac PM 60/40. Measurements of potassium, calcium, sodium, magnesium, and phosphorus were obtained at baseline and at 30 min, 60 min, and 24 h following patiromer administration.

RESULTS

Following pre-treatment with patiromer, the potassium concentration of both formulas decreased. This effect was mild with the lowest dose but increased in a dose-dependent fashion. Treating for 60 min or 24 h did not yield substantially greater effects than treating for 30 min. Calcium levels increased in both formula groups, mostly in a dose-dependent fashion. Changes in magnesium, sodium, and phosphorus were also seen after patiromer pre-treatment.

CONCLUSIONS

Pre-treatment with patiromer decreases the potassium concentration of infant formula. Calcium levels increased after treatment as expected with the majority of ion exchange occurring in 30 min. Treatment of formula with patiromer shows promise as a unique option for managing hyperkalemia.

The new Clinical Kidney Journal, 4 years later

The February 2015 issue of ckj started a new era with renewed efforts to be useful to the training and practicing nephrologists and a new focus on Clinical and Translational Nephrology. Four years later, it has become a truly global journal with contributors and readers from all over the world. The increase in quality of the published material has resulted in a nearly exponential growth of citations. Since 2016, ckj is listed in the new Emerging Sources Citation Index (ESCI) database from Clarivate Analytics and from January 2019 it will be listed in the full Science Citation Index. ckj will therefore receive its first official impact factor based upon 2018 citation to 2016 and 2017 articles. While no official impact factor was awarded for 2017, the estimated impact factors calculated from data available in Clarivate's Web of Science database rose to 2.987 in 2017, which would correspond to an estimated journal impact factor percentile of 72.4% in the Urology and Nephrology field.

Optimizing Enteral Nutrition for Growth in Pediatric Chronic Kidney Disease (CKD)

Growth in pediatric Chronic Kidney Disease is important for long-term outcomes including final adult height and cognitive function. However, there are many barriers for children with chronic kidney disease to achieve adequate nutritional intake to optimize growth. This review highlights these unique concerns, including route of nutrition, dialysis contributions and biochemical indices. Fitting the enteral feeding to the patients' needs involves choosing an appropriate product or products, limiting harmful nutrients in excess, notably aluminum, and altering for electrolyte and micronutrient needs. Unique adjustments to the enteral regimen include accommodating volume needs, optimizing macronutrient ratios, specific electrolyte adjustments, the blending of products together, and adjustments made to consider patient and family psychosocial needs. When a holistic approach to medical nutrition therapy is applied, taking the above factors into consideration, adequate intake for growth of the child with CKD is achievable.

Let food be thy medicine and medicine be thy food?

Ensuring adequate nutrition in children with chronic kidney disease whilst avoiding hyperkalaemia can be a difficult balance to achieve. Pre-treatment of feeds, whether milk, formula or enteral nutrition, with sodium polystyrene sulfonate (SPS) is practiced in some paediatric centres internationally. Such treatments are purported to avoid the potentially serious complications of direct administration of SPS, such as intestinal necrosis, aspiration pneumonitis and metabolic alkalosis to name but a few. Although described some 45 years ago, this study by Palma et al. is only the second retrospective study to describe the clinical consequence of pre-treating feeds with SPS with the majority of earlier studies describing only the in vitro effects of this method. Whilst effective in reducing serum potassium, the authors justifiably highlight the high incidence of complications, such as hypokalaemia (31.6%) and hypernatraemia (26.3%). We have further highlighted this with a summary of the available literature on this subject demonstrating the gross alterations of the electrolyte composition of feeds following SPS pre-treatment and clinical complications in its application. We heartily agree and support the conclusion by Palma et al. that where this therapy is practiced, close monitoring of electrolytes is essential and much more work is needed to identify those patient cohorts for which this can indeed be considered a safe and effective intervention.