What is the best course of action for a 10-month-old infant with persistent vomiting for 1 week?

Management of Persistent Vomiting in a 10-Month-Old Infant

For a 10-month-old with one week of persistent vomiting, immediately assess hydration status and rule out surgical emergencies—particularly pyloric stenosis, intussusception, and malrotation—then initiate oral rehydration therapy with small, frequent volumes while continuing age-appropriate feeding. 1

Immediate Assessment Priorities

Red Flag Symptoms Requiring Urgent Evaluation

• Bilious (green) vomiting indicates intestinal obstruction distal to the ampulla of Vater and constitutes a surgical emergency until proven otherwise 1, 2
• Projectile vomiting pattern suggests possible pyloric stenosis, though this typically presents between 2-8 weeks of age 1
• Bloody vomit or "currant jelly" stools indicate mucosal damage and possible intussusception 2
• Abdominal distension, lethargy, or inconsolable crying with leg drawing suggest mechanical obstruction 1, 2
• Poor weight gain or weight loss elevates concern from benign reflux to gastroesophageal reflux disease requiring intervention 1

Hydration Status Assessment

Evaluate dehydration severity using clinical signs, as physical examination is the most reliable method: 3, 4

• Mild dehydration (3-5% deficit): Slightly decreased urine output, normal mental status 3
• Moderate dehydration (6-9% deficit): Sunken fontanelle, dry mucous membranes, decreased skin turgor, prolonged capillary refill (>2 seconds) 3
• Severe dehydration (≥10% deficit): Severe lethargy, altered consciousness, cool extremities, poor perfusion, rapid deep breathing indicating acidosis 3

Capillary refill time correlates well with fluid deficit, though fever and ambient temperature affect this measurement 3, 5

Diagnostic Approach

When Imaging Is Indicated

• If projectile vomiting with suspicion for pyloric stenosis: abdominal ultrasound is the initial study of choice 1
• If bilious vomiting: obtain abdominal X-ray immediately to identify intestinal obstruction, followed by upper GI series if obstruction confirmed 2
• If passing gas and stool regularly without bilious vomiting: mechanical obstruction is unlikely and imaging may not be necessary 1

Laboratory Studies

Laboratory tests are rarely needed for typical gastroenteritis but consider serum electrolytes and bicarbonate if moderate-to-severe dehydration is present 3, 5

Management Algorithm

For Non-Bilious Vomiting Without Red Flags (Most Likely Viral Gastroenteritis)

Rehydration Phase:

• Administer oral rehydration solution (ORS) in small, frequent volumes: 5 mL every minute initially using a spoon or syringe 3, 1
• For mild dehydration: give 50 mL/kg ORS over 2-4 hours 3
• For moderate dehydration: give 100 mL/kg ORS over 2-4 hours 3
• Simultaneous correction of dehydration often lessens vomiting frequency 3, 1

Maintenance Phase (After Rehydration):

• Continue full-strength formula or breast milk immediately—do not dilute or withhold feeds 3, 1
• Replace ongoing losses: 10 mL/kg ORS for each vomiting episode 3, 1
• Resume age-appropriate solid foods immediately, including starches, cereals, yogurt, fruits, and vegetables 3
• Avoid foods high in simple sugars and fats 3

Antiemetic Consideration

Ondansetron (0.2 mg/kg oral, maximum 4 mg) may be considered only if persistent vomiting prevents oral intake entirely 1, 6

• Evidence shows ondansetron reduces vomiting, facilitates oral rehydration, and decreases need for IV hydration 7, 5, 4
• However, antiemetics are generally NOT indicated for routine viral gastroenteritis in infants this young 1
• Use judiciously only when vomiting hinders oral rehydration therapy 6, 7

When to Escalate Care

Immediate hospitalization and IV rehydration required for: 3

• Severe dehydration (≥10% deficit) with signs of shock
• Inability to tolerate oral rehydration despite ondansetron trial
• Bilious vomiting (surgical consultation mandatory) 1, 2

Critical Parent Instructions

Instruct parents to return immediately or call if: 1

• Vomiting becomes projectile or bilious (green color)
• Decreased urine output (fewer than 4 wet diapers in 24 hours)
• Lethargy or altered mental status
• Bloody vomit or stool
• Inability to keep down any fluids

Common Pitfalls to Avoid

• Do not use cola drinks or other inappropriate beverages for rehydration—they contain insufficient sodium and excessive sugar that worsens diarrhea 8
• Do not routinely use lactose-free formula—it has no demonstrated benefit and delays appropriate nutrition 3, 8
• Do not withhold feeds after rehydration—early refeeding shortens illness duration 3, 8
• Do not confuse this presentation with pyloric stenosis if the infant is 10 months old, as pyloric stenosis typically presents at 2-8 weeks of age 1, 2