SHM Converge Scientific Abstract ePoster Gallery-Beyond Gastroenteritis: Diagnostic Anchoring Delays Recognition of Metabolic Disorder in an Infant

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This case highlights how diagnostic anchoring on gastroenteritis can delay recognition of a serious metabolic disorder in an infant. A previously healthy, unvaccinated 9-month-old girl with no newborn screen presented after 3 days of progressive non-bilious, non-bloody vomiting following exposure to a sick child. She had no fever or diarrhea, then became lethargic with decreased urine output. On exam she appeared dehydrated and somnolent.<br /><br />Initial testing after fluid resuscitation revealed profound high-anion-gap metabolic acidosis with ketonuria. Her symptoms were initially attributed to gastroenteritis, and she received repeated normal saline boluses. Although the metabolic acidosis improved, she remained somnolent and encephalopathic, prompting reassessment. Ammonia was normal, but brain MRI showed diffuse cerebral edema and symmetric basal ganglia and thalamic abnormalities suggestive of a metabolic encephalopathy.<br /><br />Genetics evaluation and plasma amino acid testing confirmed maple syrup urine disease (MSUD), with elevated leucine, valine, and alloisoleucine. Subsequent genetic testing identified two pathogenic DBT variants, consistent with intermittent MSUD. She was treated with isoleucine, valine, and a low-leucine formula via nasogastric tube. Her mental status gradually improved, leucine levels declined, and she returned to baseline before discharge.<br /><br />The report emphasizes two key lessons: isolated or progressive vomiting in infants should not be assumed to be gastroenteritis, especially when diarrhea and fever are absent; and systemic barriers such as missed newborn screening and delayed medical care can postpone diagnosis of life-threatening inborn errors of metabolism. Early recognition is critical to prevent irreversible neurologic injury.

Asset Subtitle

Lindsay Podraza

Meta Tag

Author List Lindsay Podraza, Maheshwor Kafle

Category Clinical Vignettes

Concept Vomiting

Concept Inborn Error of Metabolism

Concept Maple Syrup Urine Disease

Concept Metabolic Emergency

Concept Anion Gap Metabolic Acidosis

Distinguished Non-Finalist

Presenter Organization Phoenix Children's Hospital

Presenting Author Lindsay Podraza

Track Pediatric

Keywords

maple syrup urine disease

MSUD

infant vomiting

metabolic acidosis

ketonuria

encephalopathy

cerebral edema

basal ganglia abnormalities

inborn error of metabolism

newborn screening

Vomiting

Inborn Error of Metabolism

Maple Syrup Urine Disease

Metabolic Emergency

Anion Gap Metabolic Acidosis