SHM Converge Scientific Abstract ePoster Gallery-Growth on Hold: When Hyponatremia Tells a Bigger Story

Pdf Summary

This case describes a 4-month-old full-term infant with poor feeding, vomiting, and severe growth faltering. Although failure to thrive is most often due to inadequate caloric intake, this infant also had significant electrolyte abnormalities, including hyponatremia (Na 121 mmol/L) and mild hyperkalemia (K 6.2 mmol/L), which suggested an underlying organic cause.<br /><br />On exam, the infant was euvolemic and well appearing but had a poor suck and exaggerated gag reflex. During hospitalization, hyponatremia was treated with IV normal saline and sodium acetate, and an NG tube was placed because of ongoing feeding difficulty. Because the infant continued to need sodium supplementation, aldosterone and renin levels were obtained and were markedly elevated. Genetic testing later identified a pathogenic NR3C2 variant, confirming autosomal dominant pseudohypoaldosteronism type 1 (PHA1).<br /><br />PHA1 is caused by resistance to aldosterone, leading to renal sodium wasting and impaired potassium excretion. The autosomal dominant form is typically less severe and limited to the kidneys, but it can still present in infancy with poor weight gain, hyponatremia, hyperkalemia, and metabolic acidosis. Sodium supplementation is often needed during early childhood to support growth and prevent crises.<br /><br />The patient was discharged on NaCl supplementation with stabilized electrolytes and improved weight gain. His growth chart showed faltering beginning around 2 months of age, followed by recovery toward normal curves by 6 months.<br /><br />Key takeaways: infants with weight faltering plus vomiting or electrolyte abnormalities should be evaluated for underlying disease, not just feeding issues. If chronic electrolyte disturbance is suspected, serum and urine studies should ideally be obtained before correction to avoid misinterpretation and diagnostic delay.

Asset Subtitle

Kathryn Westphal

Meta Tag

Author List Connor J. Cook, Danielle Abdallah, Kathryn Westphal, Maria Widmann

Category Clinical Vignettes

Concept Weight Faltering

Concept Pseudohypoaldosteronism Type 1

Concept Hyponatremia

Concept Hyperkalemia

Concept Aldosterone Resistance

Distinguished Non-Finalist

Presenter Organization Nationwide Children's Hospital and Ohio State University College of Medicine

Presenting Author Kathryn Westphal

Track Pediatric

Keywords

failure to thrive

hyponatremia

hyperkalemia

pseudohypoaldosteronism type 1

aldosterone resistance

NR3C2 variant

infant vomiting

poor feeding

sodium supplementation

growth faltering

Weight Faltering

Pseudohypoaldosteronism Type 1

Hyponatremia

Hyperkalemia

Aldosterone Resistance