What is the best course of treatment for a 4-year-old patient (pediatric patient) with episodes of vomiting and loose stools, weighing 15.3 kg, and having a blood pressure of 100/80 mmHg?

Management of 4-Year-Old with Acute Gastroenteritis and Dehydration

Immediate Assessment

This 4-year-old with 4 episodes of vomiting and 4 episodes of loose stools requires immediate oral rehydration therapy (ORS) with small, frequent volumes, and you should assess for moderate dehydration given the multiple episodes of fluid loss. 1

Determine Dehydration Severity

Based on the clinical presentation with multiple vomiting and diarrheal episodes, assess for:

• Skin turgor and capillary refill - prolonged skin tenting and delayed capillary refill indicate moderate dehydration (6-9% deficit) 2
• Mucous membrane moisture - dry mucous membranes suggest at least mild dehydration 2
• Mental status and activity level - lethargy or altered consciousness would indicate severe dehydration requiring IV therapy 2
• Urine output - decreased frequency suggests ongoing fluid deficit 1

This child most likely has moderate dehydration (6-9% deficit) given 4 episodes each of vomiting and diarrhea, and requires 100 mL/kg of ORS over 2-4 hours. 2, 1

Rehydration Protocol

For Moderate Dehydration (Most Likely Scenario)

Administer 1,530 mL of ORS over 2-4 hours (100 mL/kg × 15.3 kg), given in small frequent volumes to prevent triggering more vomiting. 2, 1

Critical technique to prevent vomiting perpetuation:

• Give 5-10 mL every 1-2 minutes using a teaspoon, syringe, or medicine dropper - never allow the child to drink large volumes rapidly from a cup, as this will trigger more vomiting 1, 3
• Gradually increase volume as tolerated 2

Replace Ongoing Losses

Give 10 mL/kg (153 mL) of ORS for each additional watery stool and 2 mL/kg (31 mL) for each additional vomiting episode during the rehydration period. 2, 3

Ondansetron as Adjunctive Therapy

Consider ondansetron if vomiting prevents adequate oral intake despite proper small-volume technique, as it improves ORS tolerance and reduces need for IV therapy. 2, 1

• Dose: 4 mg orally (or 0.15 mg/kg IV, maximum 4 mg) for this 4-year-old 4
• Ondansetron significantly reduces ORT failure (31% vs 62% in placebo) and increases ORS consumption by approximately 90 mL 5
• May cause increased stool frequency as a side effect, but this does not worsen outcomes 2

Reassessment After 2-4 Hours

Reassess hydration status by examining:

• Skin turgor and mucous membrane moisture 1
• Mental status and activity level 1
• Urine output 1
• Weight change if possible 2

If still dehydrated, reestimate fluid deficit and restart rehydration therapy; if rehydrated, progress to maintenance phase with early feeding. 2

Dietary Management

Resume age-appropriate diet immediately after rehydration is complete (within 4 hours) - do not delay feeding. 2, 1

• Continue usual diet with starches, cereals, yogurt, fruits, and vegetables 2
• Avoid foods high in simple sugars and fats 2, 6
• Early feeding improves nutritional outcomes and is as safe as delayed feeding 2

Critical Pitfalls to Avoid

Do NOT give antimotility agents (loperamide) - these are absolutely contraindicated in all children under 18 years due to risk of ileus, lethargy, and reported deaths. 2, 3

Do NOT give antibiotics - this is uncomplicated watery diarrhea with vomiting, most likely viral gastroenteritis requiring only supportive care. 1, 3

• Antibiotics should only be considered if watery diarrhea persists >5 days, dysentery (bloody diarrhea) develops, high fever is present, or stool cultures confirm a specific treatable pathogen 2, 3

Do NOT allow rapid drinking from a cup or bottle - this perpetuates the vomiting cycle. 1

When to Escalate to IV Therapy

Switch to IV isotonic fluids (lactated Ringer's or normal saline) if:

• Severe dehydration develops (≥10% deficit with lethargy, prolonged skin tenting >2 seconds, cool extremities, signs of shock) 2
• ORS therapy fails despite proper small-volume technique and ondansetron 3
• Altered mental status develops 3
• The child cannot tolerate even small volumes orally 1

For severe dehydration, give 20 mL/kg boluses of lactated Ringer's or normal saline until pulse, perfusion, and mental status normalize. 2

Disposition and Follow-Up

Instruct parents to return immediately if the child:

• Becomes increasingly lethargic or irritable 6
• Has no urine output for 8-12 hours 6
• Develops intractable vomiting despite ondansetron 6
• Shows signs of worsening dehydration 6

Arrange follow-up with primary care within 24-48 hours if symptoms persist. 6