TOPIC 14: Emesis (Infants) – Know the differential diagnosis and evaluation of emesis in an infant

OFFICIAL ABP TOPIC:

Emesis (Infants) – Know the differential diagnosis and evaluation of emesis in an infant

BACKGROUND

Vomiting is a common presenting symptom in infants that has a wide differential diagnosis spanning gastrointestinal, neurologic, metabolic, infectious, and other etiologies. While often benign and self-limited, emesis in infants can also be a sign of a serious underlying disorder.

DIFFERENTIAL DIAGNOSIS OF EMESIS IN INFANTS

TABLE 1

DISORDER	TYPICAL CLINICAL FEATURES
Gastrointestinal Obstruction
Pyloric stenosis	Forceful vomiting, typically nonbilious, beginning at 3-6 weeks of age, hypochloremic metabolic alkalosis, palpable “olive”
Malrotation with volvulus	Sudden onset of bilious vomiting and acute abdomen, starting at any age
Intestinal atresia, stenosis, or duplication	Bilious vomiting (if lesion distal to ampulla of Vater) and gastric or abdominal distension, usually presenting within hours or days of birth
Intussusception	Sudden-onset intermittent colicky pain, currant jelly stools
Hirschsprung disease	Abdominal distension, failure to pass meconium within 48 hours, sometimes with bilious emesis; can present with enterocolitis (fever, vomiting, diarrhea, septic shock)
Other Gastrointestinal Causes
Uncomplicated GER	Infant with regurgitation but otherwise healthy (happy spitter)
Overfeeding	Frequent small-volume emesis, normal growth and development
Infant rumination syndrome	Re-swallowing of regurgitated food within minutes of eating; onset typically between 3-8 months old
Viral gastroenteritis	Sudden onset, usually with diarrhea and ill contacts
Necrotizing enterocolitis (premature infants)	Bilious emesis, bloody stools, abdominal distension, wall erythema/discoloration, acute decompensation
GERD with esophagitis	Frequent regurgitation with concerning symptoms (irritability, feeding refusal, poor weight gain)
Food protein-induced enterocolitis syndrome (FPIES)	Severe vomiting, diarrhea, lethargy in acute FPIES; chronic FPIES with intermittent vomiting, diarrhea, poor growth
Eosinophilic esophagitis or gastroenteritis	Feeding aversion, weight loss, hypoalbuminemia; can present with postprandial vomiting mimicking pyloric stenosis

TABLE 1 CONTINUED…

DISORDER	TYPICAL CLINICAL FEATURES
Neurologic
Hydrocephalus	Persistent forceful emesis, bulging fontanelle, altered mental status, focal neurologic deficits, emesis with position changes
Subdural hematoma	Unexplained emesis, altered mental status, seizures in infant with history of possible trauma
Metabolic/Endocrine
Galactosemia	Vomiting, jaundice, hepatomegaly, poor weight gain within days of starting breast milk or lactose-containing formula
Hereditary fructose intolerance	Vomiting, hypoglycemia after feeds with fructose/sucrose (fruits, juices, medications)
Urea cycle defects, organic acidemias	Recurrent vomiting, lethargy, poor feeding, ± hyperammonemia, metabolic acidosis
Congenital adrenal hyperplasia	Vomiting, dehydration, hypotension, hyponatremia, hyperkalemia; may have atypical genitalia (females)

EVALUATION OF EMESIS IN INFANTS

HISTORY

Emesis: Onset, frequency, amount, forcefulness, content (bilious, bloody, undigested food)
Associated symptoms: Fever, diarrhea, bloody stools, abdominal pain/distension, lethargy
Feeding: Formula or breast milk, volume, recent diet changes, timing of emesis relative to feeds
Urine output and wet diapers
Medications and recent immunizations
Ill contacts: Gastroenteritis, HSV
Growth and development
Past medical history
Family history: Gastrointestinal disorders, metabolic diseases, cystic fibrosis

PHYSICAL EXAM

Vital signs
Growth parameters (weight, length, head circumference): Rapid head growth may be a sign of hydrocephalus
Hydration status: Tears, mucous membranes, skin turgor, sunken eyes/fontanelle
General appearance: Lethargy, irritability, consolability
Head: Fontanelle fullness, signs of trauma
Abdomen: Distension, tenderness, visible peristalsis, palpable mass, bowel sounds
Genitourinary: Atypical genitalia (congenital adrenal hyperplasia)
Anus: Patency, explosive stools with rectal exam (blast sign suggestive of Hirschsprung’s disease)
Neurologic: Mental status, tone, reflexes
Skin: Jaundice, erythema/discoloration, petechiae/purpura
Unusual odor may suggest a metabolic disorder (e.g., musty odor in phenylketonuria)

RED FLAGS FOR SERIOUS CAUSES OF EMESIS IN INFANTS

Acute bilious emesis indicates a surgical emergency (e.g., malrotation with midgut volvulus, intestinal atresia or stenosis, necrotizing enterocolitis in premature infants, incarcerated hernia).
Hematemesis: Differential includes swallowed maternal blood during birth (benign), esophagitis, Mallory-Weiss tear, coagulopathy (e.g., Vitamin K deficiency bleeding), gastritis/stress ulcers.
Abdominal distension, tenderness, or mass.
Altered mental status, irritability, lethargy.
Jaundice in newborns >2 weeks old.
Failure to thrive.

DIAGNOSTIC TESTING

Lab tests: CBC, electrolytes, glucose, liver enzymes, urinalysis.
Abdominal x-ray: If obstruction suspected, may show dilated loops of bowel, air-fluid levels.
Abdominal ultrasound: Malrotation, hypertrophic pyloric stenosis, intussusception, masses.
Upper GI contrast study: Malrotation, obstruction, pyloric stenosis.
Metabolic screening: For persistent or unusual symptoms: ammonia, lactate, pyruvate, organic/amino acids, acylcarnitine.
Brain MRI: For hydrocephalus.
Endoscopy +/- biopsy: For suspected eosinophilic esophagitis or gastroenteritis.
Specialized testing: Based on differential (e.g., sweat chloride for cystic fibrosis).

PHYSICAL EXAM FINDINGS AND DIAGNOSTIC CONSIDERATIONS

FINDING	DIAGNOSTIC CONSIDERATIONS
Nonspecific
Tachycardia	Dehydration, sepsis, metabolic acidosis, bowel ischemia
Jaundice	Conjugated – Biliary atresia, metabolic liver disease
Jaundice	Unconjugated – Physiologic, breast milk, hemolysis, Gilbert syndrome
Altered mental status	Sepsis, meningitis, intracranial hemorrhage/mass, inborn error of metabolism, ingestion
Poor growth/malnutrition	Malabsorption, FPIES, eosinophilic disorders, metabolic disorders, pyloric stenosis
Abdominal
Distension	Bowel obstruction, ileus, Hirschsprung disease, necrotizing enterocolitis
Tenderness/peritoneal signs	Intussusception, peritonitis, obstruction, volvulus
Visible bowel loops	Obstruction, Hirschsprung disease
Abdominal mass	Intussusception, tumor (neuroblastoma, Wilms), pyloric stenosis (“olive”)
Jaundice + hepatomegaly	Biliary atresia, idiopathic neonatal hepatitis, metabolic liver disease
Other
Bulging fontanelle	Increased intracranial pressure, hydrocephalus, meningitis
Inguinal mass/fullness	Incarcerated inguinal hernia
Rectal bleeding	Milk protein allergy, FPIES, Meckel’s diverticulum, intussusception

REFERENCES

https://www.uptodate.com/contents/approach-to-the-infant-or-child-with-nausea-and-vomiting

https://publications.aap.org/pediatricsinreview/article/39/7/342/35176/Vomiting-in-Children

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