What is the best treatment approach for a 5-month-old baby experiencing vomiting?

Treatment of Vomiting in a 5-Month-Old Baby

The primary treatment for vomiting in a 5-month-old infant is oral rehydration solution (ORS) administered in small, frequent volumes (5 mL every minute initially) using a spoon or syringe, with continuation of normal feeding once rehydration is achieved. 1

Immediate Management Approach

Oral Rehydration Therapy

• Administer ORS in small, frequent volumes starting at 5 mL every minute using a spoon or syringe with close supervision to guarantee gradual progression in the amount taken 1
• Replace each vomiting episode with approximately 10 mL/kg of ORS 2
• Simultaneous correction of dehydration often lessens the frequency of vomiting itself 1
• This approach is successful in more than 90% of cases 3

Feeding Management

• For breastfed infants: Continue nursing on demand without interruption 1, 2
• For formula-fed infants: Resume full-strength formula immediately upon rehydration in amounts sufficient to satisfy energy requirements 1, 2
• Lactose-free or lactose-reduced formulas are preferred initially, but full-strength lactose-containing formulas can be used under supervision if lactose-free options are unavailable 1

Assessment of Severity

Hydration Status Evaluation

• Assess for dehydration severity: mild (3-5% deficit), moderate (6-9% deficit), or severe (≥10% deficit) 2
• Evaluate capillary refill time, which correlates well with fluid deficit 2
• Check for decreased urine output (fewer than 4 wet diapers in 24 hours) 2

Red Flag Symptoms Requiring Urgent Evaluation

• Bilious (green) vomiting - indicates possible intestinal obstruction and requires immediate surgical consultation 2, 4
• Projectile vomiting - may indicate pyloric stenosis, especially between 2-8 weeks of age 2
• Blood in vomit or stool 2
• Altered mental status, lethargy, or irritability 1
• Abdominal distension 2, 4
• Poor weight gain 2

Role of Antiemetic Medications

When Antiemetics Are NOT Indicated

• Antiemetics are generally NOT recommended for routine viral gastroenteritis in infants this young 2
• The focus should remain on appropriate fluid therapy rather than suppressing the protective vomiting reflex 2

Limited Use of Ondansetron

• Ondansetron (0.15-0.2 mg/kg oral, maximum 4 mg) may be considered only if persistent vomiting prevents oral intake entirely and impedes oral rehydration therapy 2, 5
• This should be used judiciously and only after adequate assessment 2, 6
• Evidence supports ondansetron's efficacy in facilitating ORS administration, but it is not routinely recommended for all cases 7, 8

Common Pitfalls to Avoid

• Do not delay evaluation if vomiting is bilious - this is a surgical emergency until proven otherwise 2, 4
• Do not use antidiarrheal or antimotility agents - these can cause serious side effects and are not effective in reducing fluid losses 2
• Do not withhold breastfeeding - breast milk should continue on demand 1, 2
• Do not give intravenous fluids if oral/nasogastric rehydration is feasible - oral rehydration is successful in over 90% of cases 3

When to Seek Immediate Medical Attention

Instruct Parents to Return If:

• Vomiting becomes projectile or bilious (green) 2
• Signs of dehydration develop (decreased urine output, dry mucous membranes, lethargy) 1, 2
• Infant becomes irritable, lethargic, or has altered mental status 1
• Intractable vomiting persists despite ORS administration 1
• Poor weight gain is noted on follow-up 2

Special Considerations for 5-Month-Old Infants

At 5 months of age, this infant is in the high-risk period where morbidity and mortality from dehydration are most significant 1. The key is preventing dehydration through early, aggressive oral rehydration rather than treating established dehydration 1. Most cases of vomiting at this age are due to viral gastroenteritis and are self-limited, but vigilance for red flag symptoms is essential 2, 9.