What is the appropriate management of acute vomiting in a 4‑year‑old child weighing about 12 kg?

Management of Acute Vomiting in a 4-Year-Old Child

For a 4-year-old child (approximately 12 kg) with acute vomiting, begin oral rehydration therapy immediately using small, frequent volumes of oral rehydration solution (5 mL every 1-2 minutes), gradually increasing as tolerated, while assessing for dehydration severity to guide fluid replacement volumes. 1

Initial Assessment of Dehydration Status

Rapidly evaluate the child's hydration status through focused clinical examination:

• Check capillary refill time – the most reliable predictor of dehydration in this age group 2
• Examine skin turgor – pinch the skin and observe for tenting (prolonged tenting >2 seconds indicates severe dehydration) 2
• Assess mucous membranes – dry membranes suggest at least moderate dehydration 1
• Evaluate mental status – lethargy or altered consciousness indicates severe dehydration requiring immediate IV therapy 3
• Obtain body weight – essential for calculating fluid deficit and monitoring treatment response 2

Dehydration Classification

• Mild (3-5% fluid deficit): Increased thirst, slightly dry mucous membranes 1
• Moderate (6-9% fluid deficit): Loss of skin turgor, dry mucous membranes, decreased urine output 1
• Severe (≥10% fluid deficit): Severe lethargy, prolonged skin tenting, cool extremities with poor perfusion, rapid deep breathing 2

Rehydration Strategy Based on Severity

If Mild Dehydration (Most Common Scenario)

• Administer 50 mL/kg of ORS over 2-4 hours – for this 12 kg child, give approximately 600 mL total 1
• Use the small-volume technique: Start with 5 mL (one teaspoon) every 1-2 minutes using a spoon or syringe 3, 1
• Gradually increase volume as vomiting subsides – simultaneous correction of dehydration often lessens vomiting frequency 3
• Critical pitfall to avoid: Do NOT allow the thirsty child to drink large volumes ad libitum, as this worsens vomiting 1

If Moderate Dehydration

• Administer 100 mL/kg of ORS over 2-4 hours – for this 12 kg child, give approximately 1200 mL total 1
• Continue small-volume technique initially, then advance as tolerated 1
• Consider nasogastric administration if the child cannot tolerate oral intake despite small volumes 3

If Severe Dehydration (Medical Emergency)

• Immediately administer 20 mL/kg IV boluses of Ringer's lactate or normal saline until pulse, perfusion, and mental status normalize 3, 2
• Do NOT delay – this is a life-saving intervention requiring immediate action 2
• Transition to ORS once circulation is restored to complete rehydration 2

Ongoing Loss Replacement During Maintenance

After initial rehydration is complete:

• Replace 10 mL/kg of ORS for each watery stool – approximately 120 mL per stool for this 12 kg child 3, 1
• Replace 2 mL/kg of ORS for each vomiting episode – approximately 24 mL per episode 3, 1
• Continue replacement until vomiting and diarrhea resolve 1

Nutritional Management

• Resume age-appropriate diet immediately upon rehydration – include starches, cereals, yogurt, fruits, and vegetables 3, 1
• Avoid foods high in simple sugars and fats during the acute phase 3
• Do NOT impose "bowel rest" – there is no justification for withholding food 2

Pharmacological Considerations

Ondansetron (May Be Considered)

• Can be given to children >4 years to facilitate oral rehydration when vomiting prevents adequate intake 1
• Only administer AFTER adequate hydration is achieved – not as first-line therapy 1
• Evidence shows increased ORT success rates and reduced need for IV therapy 1

Absolutely Contraindicated Medications

• Antimotility drugs (loperamide) are ABSOLUTELY CONTRAINDICATED in all children <18 years due to risks of respiratory depression and serious cardiac adverse reactions 1, 2
• Prochlorperazine should NOT be used in children with acute illnesses or dehydration due to increased risk of extrapyramidal reactions 4

Antibiotics (Rarely Indicated)

• Do NOT routinely prescribe antibiotics for acute vomiting/gastroenteritis 3
• Consider antibiotics only if: dysentery (bloody diarrhea) is present, high fever occurs, or watery diarrhea persists >5 days 3

Reassessment and Monitoring

• Reassess hydration status after 2-4 hours of rehydration therapy 1, 2
• If rehydrated: transition to maintenance phase with ongoing loss replacement 2
• If still dehydrated: recalculate fluid deficit and continue rehydration 5

Warning Signs Requiring Immediate Medical Attention

Instruct caregivers to return immediately if:

• Severe lethargy or difficulty arousing the child 2
• Intractable vomiting that prevents any fluid intake 1
• Bloody diarrhea develops 1
• High stool output (>10 mL/kg/hour or many watery stools) 1
• Decreased urine output (fewer than 3 wet diapers/voids in 24 hours) 2
• Sunken eyes or increased thirst despite treatment 2

Common Pitfalls to Avoid

• Do NOT use sports drinks, juice, or soft drinks for rehydration – they contain inadequate sodium and excessive osmolality that worsens symptoms 3, 2
• Do NOT mix ORS packets with incorrect water volumes – provide detailed written instructions 1
• Do NOT rely solely on sunken fontanelle or absent tears for dehydration assessment – these are less reliable than capillary refill and skin turgor 2
• Do NOT assume antibiotics are needed – most acute vomiting/gastroenteritis in this age is viral and self-limited 2