What is the best course of treatment for a 6-year-old child presenting with vomiting?

Management of Vomiting in a 6-Year-Old Child

The best treatment for a 6-year-old with vomiting is oral rehydration therapy (ORS) using small, frequent volumes (5 mL every 1-2 minutes), with ondansetron 0.2 mg/kg (maximum 4 mg) reserved for persistent vomiting that prevents adequate oral intake. 1, 2

Initial Assessment: Rule Out Emergencies First

Before initiating treatment, immediately assess for red flag signs that require emergency intervention:

• Bilious (green) vomiting suggests intestinal obstruction or malrotation with volvulus and requires immediate surgical consultation 1, 3, 4
• Projectile vomiting may indicate pyloric stenosis or other obstructive conditions requiring urgent evaluation 1, 3
• Altered mental status, severe lethargy, or inability to arouse suggests severe dehydration, sepsis, or central nervous system pathology 2, 3
• Abdominal distension or severe tenderness necessitates emergency evaluation 1, 3

Assess Hydration Status

Determine the degree of dehydration to guide treatment intensity:

• Mild dehydration (3-5% fluid deficit): Slightly dry mucous membranes, increased thirst, normal mental status 2, 3
• Moderate dehydration (6-9% fluid deficit): Sunken eyes, decreased skin turgor (skin tenting), reduced urine output, dry mucous membranes 2, 3
• Severe dehydration (≥10% fluid deficit): Severe lethargy, prolonged skin tenting (>2 seconds), cool extremities, minimal urine output, signs of shock 2, 3

Rehydration Protocol: The Foundation of Treatment

For Mild to Moderate Dehydration

Administer ORS in small, frequent volumes—this is the single most important intervention:

• Start with 5 mL of ORS every 1-2 minutes using a spoon or syringe 1, 3
• Gradually increase volume as tolerated 1
• Target 50-100 mL/kg over 2-4 hours for moderate dehydration 3
• Replace each vomiting episode with an additional 2 mL/kg of ORS 3
• Over 90% of children with vomiting can be successfully rehydrated orally when this approach is followed 1, 3

Critical pitfall to avoid: Do not give large volumes of ORS at once—this triggers more vomiting. Small, frequent volumes are essential for success. 1, 3

For Severe Dehydration

• Initiate immediate intravenous rehydration with 20 mL/kg boluses of lactated Ringer's or normal saline until vital signs normalize 2, 3
• Once stabilized, transition to ORS for remaining deficit replacement 2

Ondansetron Use: When and How

Ondansetron should be considered only after attempting oral rehydration, not as first-line therapy:

• Indication: Children ≥4 years with persistent vomiting that impedes oral rehydration 2, 1, 3
• Dosing: 0.2 mg/kg orally (maximum 4 mg) 2, 1, 5, 4
• Timing: Administer only after initial ORS attempts, to facilitate tolerance of continued oral rehydration 2, 1, 3
• Evidence: Ondansetron reduces vomiting episodes, improves oral intake success, and decreases need for IV hydration 6, 7

Important caveat: Antiemetics are not a substitute for proper fluid and electrolyte therapy—they are adjunctive only after hydration efforts begin. 2, 1

Nutritional Management During Illness

Continue age-appropriate nutrition as soon as the child can tolerate it:

• Continue usual diet during or immediately after rehydration 2, 1
• Recommended foods: Starches (rice, potatoes, noodles, crackers), cereals, yogurt, vegetables, fresh fruits, bananas 2, 1, 3
• Avoid: Foods high in simple sugars (soft drinks, undiluted apple juice, Jell-O, presweetened cereals) and high-fat foods 2, 1, 3

The "BRAT diet" (bananas, rice, applesauce, toast) is reasonable but should not be prolonged, as it may provide inadequate energy and protein. 2

Medications to AVOID

Never administer antimotility drugs (loperamide) to children <18 years with vomiting and diarrhea:

• These agents can cause serious complications including ileus, toxic megacolon, and death 2, 3
• Six deaths were reported in children given loperamide in one series 2

Avoid nonspecific antidiarrheal agents (kaolin-pectin, adsorbents) as they do not reduce symptom duration and may increase electrolyte losses. 2

When to Return for Emergency Care

Instruct parents to seek immediate medical attention if:

• Vomiting becomes bilious (green) or bloody 1, 3
• Child becomes increasingly lethargic or difficult to arouse 1, 3
• No urine output for >8 hours 1, 3
• Signs of severe dehydration develop despite oral rehydration attempts 1, 3
• Persistent symptoms beyond 5 days, especially with high fever 3

Practical Implementation Algorithm

1. Assess for red flags (bilious vomiting, altered mental status, abdominal distension) → Emergency care if present 1, 3
2. Determine hydration status (mild, moderate, or severe) 2, 3
3. Initiate ORS with 5 mL every 1-2 minutes, gradually increasing 1, 3
4. If persistent vomiting prevents ORS after 30-60 minutes, consider ondansetron 0.2 mg/kg (max 4 mg) 2, 1, 5
5. Continue ORS after ondansetron, targeting 50-100 mL/kg over 2-4 hours 3
6. Resume age-appropriate diet as tolerated 2, 1
7. Monitor for worsening and return precautions 1, 3