What are the causes, signs, and treatment of vomiting in infancy and childhood?

Vomiting in Infancy and Childhood

Critical First Principle

Bilious vomiting at any age is a surgical emergency until proven otherwise—midgut volvulus must be excluded immediately as it is the most time-sensitive life-threatening diagnosis. 1, 2

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Causes by Age and Clinical Pattern

Newborn Period (First Week of Life)

Congenital GI abnormalities are the primary consideration:

• Midgut volvulus accounts for 20% of bilious vomiting cases in the first 72 hours and requires immediate surgical evaluation 1
• Duodenal atresia is the most common proximal obstruction, presenting with "double bubble" sign on radiograph 1
• Jejunoileal atresia presents with "triple bubble" sign and absent distal gas 1
• Meconium ileus may require therapeutic enema rather than immediate surgery 1
• Hirschsprung disease requires rectal biopsy for definitive diagnosis 1
• Vomiting typically begins within the first 2 days and is bilious, though 15% may present with nonbilious vomiting despite proximal obstruction 1

Infancy (Beyond Newborn Period)

Common causes include:

• Gastroesophageal reflux (GER) is the most common cause of nonbilious vomiting/regurgitation in infants, typically resolves with age, and is normal when associated with normal weight gain 3
• Hypertrophic pyloric stenosis (HPS) presents with forceful, projectile nonbilious vomiting, typically between 3-6 weeks of age 3
• Intussusception manifests with crampy intermittent abdominal pain (inconsolable crying, drawing up legs), "currant jelly" bloody stools, and progression to bilious vomiting 4, 5
• Viral gastroenteritis causes watery diarrhea and vomiting, most commonly in children under 2 years 3

Childhood (Older Children)

Broader differential includes:

• Acute gastroenteritis remains the leading cause of acute vomiting 6
• Appendicitis presents with vomiting accompanied by pain without complete remission, often with constipation (though diarrhea may occur) 5
• Intracranial pathology including mass lesions, increased intracranial pressure, meningitis, or encephalitis 6
• Metabolic emergencies such as diabetic ketoacidosis, inborn errors of metabolism, or uremia 6

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Red Flag Signs Requiring Urgent Evaluation

Any of these signs mandate immediate assessment and investigation:

• Bilious (green) vomitus indicates obstruction distal to the ampulla of Vater 4, 1, 2
• Bloody vomitus or "currant jelly" stools suggest mucosal damage from intussusception or other serious pathology 4, 5
• Altered sensorium or encephalopathy indicates neurologic or metabolic emergency 6
• Toxic/septic appearance or inconsolable crying 6
• Severe dehydration with prolonged skin tenting (>2 seconds), cool extremities, decreased capillary refill 3
• Acidotic breathing suggests metabolic acidosis from severe dehydration or diabetic ketoacidosis 6, 7
• Scaphoid (sunken) abdomen with bilious vomiting suggests midgut volvulus 5
• Papilledema indicates increased intracranial pressure 7

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Clinical Assessment Algorithm

Step 1: Immediate Vital Sign Assessment

• Assess airway, breathing, and circulation first 6
• Check blood pressure, as hypotension indicates severe dehydration or shock 7
• Evaluate for signs of severe dehydration: lethargy, prolonged skin tenting, cool extremities, rapid deep breathing 3

Step 2: Characterize the Vomiting

Bilious vs. Nonbilious:

• Bilious vomiting requires immediate abdominal X-ray and surgical consultation 7
• Nonbilious vomiting in infants with normal weight gain suggests benign GER 3

Forceful vs. Effortless:

• Projectile, forceful vomiting suggests pyloric stenosis or increased intracranial pressure 3
• Effortless regurgitation is typical of GER 3

Step 3: Assess Hydration Status

Mild dehydration (3-5% fluid deficit):

• Increased thirst, slightly dry mucous membranes 3

Moderate dehydration (6-9% fluid deficit):

• Loss of skin turgor, tenting of skin, dry mucous membranes 3

Severe dehydration (≥10% fluid deficit):

• Severe lethargy, prolonged skin tenting (>2 seconds), cool poorly perfused extremities, decreased capillary refill, rapid deep breathing 3

Step 4: Physical Examination Priorities

• Auscultate for bowel sounds before initiating oral therapy 3
• Careful abdominal examination including palpation for masses (intussusception), assessment for distention or scaphoid appearance 7, 5
• Examine genitalia and hernial orifices for incarcerated hernias 7
• Fundoscopic examination to assess for papilledema 7
• Obtain accurate body weight to guide rehydration therapy 3

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Diagnostic Approach

When to Image

Immediate imaging required for:

• Any bilious vomiting: obtain abdominal X-ray looking for "double bubble" (duodenal obstruction), "triple bubble" (jejunal obstruction), or air-fluid levels suggesting obstruction 1, 7
• Suspected intussusception: ultrasound is the recommended initial imaging modality 4
• Signs of GI obstruction on examination 7

Imaging generally not needed for:

• Nonbilious vomiting with normal weight gain in young infants (likely GER) 3
• Clear viral gastroenteritis pattern (watery diarrhea, vomiting, child <2 years) 3

Laboratory Testing

Indicated when:

• Any degree of dehydration is present: obtain serum electrolytes, blood gases, renal function 6
• Red flag signs are present 6
• Diagnosis is unclear after initial assessment 6

Not routinely needed for:

• Mild, self-limited vomiting without dehydration 7
• Clear benign GER in thriving infant 3

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Treatment Approach

Immediate Management Priorities

For bilious vomiting:

• Stop all oral intake immediately 6
• Insert nasogastric tube for gastric decompression 6
• Obtain urgent surgical consultation 1
• Establish IV access and begin fluid resuscitation 6

For severe dehydration:

• Establish IV access and begin rapid fluid resuscitation 3
• Monitor electrolytes and correct abnormalities 3

Rehydration Therapy

Oral rehydration is preferred when possible:

• Use oral rehydration solution (ORS) for mild to moderate dehydration 3
• Avoid antidiarrheal agents (kaolin-pectin, loperamide) as they do not reduce diarrhea volume, can cause serious side effects including ileus and death, and shift focus away from appropriate fluid therapy 3

IV rehydration indicated for:

• Severe dehydration (≥10% fluid deficit) 3
• Inability to tolerate oral fluids due to persistent vomiting 6
• Altered mental status or shock 3

Antiemetic Use

Ondansetron is indicated for:

• Children unable to take oral fluids due to persistent vomiting (dose: 0.2 mg/kg oral; 0.15 mg/kg parenteral; maximum 4 mg) 6
• Post-operative vomiting 6
• Chemotherapy-induced vomiting 6
• Cyclic vomiting syndrome 6

Domperidone is also commonly used as an alternative antiemetic 7

Antiemetics should not replace:

• Proper fluid and electrolyte management 3
• Identification and treatment of underlying surgical causes 7

Cause-Specific Management

Gastroesophageal reflux (benign):

• Parental reassurance if infant is thriving with normal weight gain 3, 7
• Typically resolves with time as lower esophageal sphincter matures 3
• Consider smaller, more frequent feedings 3

Viral gastroenteritis:

• Oral rehydration therapy is the cornerstone 3
• Early refeeding with age-appropriate diet once rehydrated 3
• Antimicrobial therapy not indicated for watery diarrhea and vomiting in children <2 years 3

Surgical conditions:

• Immediate surgical consultation and preparation for operative intervention 1, 6

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Critical Pitfalls to Avoid

• Never dismiss bilious vomiting as "just gastroenteritis"—it is a surgical emergency until proven otherwise 1, 2
• Do not rely on antidiarrheal agents (loperamide, kaolin-pectin) as they are ineffective, potentially dangerous (causing ileus and death), and distract from proper fluid management 3
• Do not assume viral gastroenteritis without considering serious non-GI causes including meningitis, sepsis, pneumonia, urinary tract infection, and metabolic disorders that can present with fever, vomiting, and loose stools 3
• Do not use antiemetics as a substitute for identifying and treating underlying surgical or metabolic emergencies—symptomatic treatment may delay specific diagnosis 7
• Do not overlook intussusception when vomiting progresses from nonbilious to bilious, especially with intermittent crying and bloody stools 4, 5
• Regular early review is essential for undifferentiated vomiting illness to ensure fulminant conditions are not missed and dehydration complications do not develop 8