What is the initial approach to managing vomiting in children?

Initial Approach to Vomiting in Children

Begin with immediate assessment of hydration status and red flag signs, then initiate oral rehydration therapy as the cornerstone of management for most children with vomiting, reserving ondansetron for cases where persistent vomiting prevents oral intake. 1, 2

Immediate Assessment Priorities

Red Flag Signs Requiring Urgent Evaluation

Immediately assess for life-threatening conditions by examining for:

• Bilious or bloody vomiting (suggests intestinal obstruction, malrotation with volvulus, or intussusception) 3
• Altered sensorium or toxic/septic appearance (suggests meningitis, encephalitis, sepsis, or metabolic crisis) 3
• Inconsolable cry, excessive irritability, or bent-over posture (suggests appendicitis, intussusception, or increased intracranial pressure) 3
• Severe dehydration or concern for symptomatic hypoglycemia 3

Hydration Status Assessment

Categorize dehydration severity by examining:

• Skin turgor, mucous membrane moisture, mental status 1, 2
• Pulse rate, capillary refill time, and urine output 1
• Mild dehydration: 3-5% fluid deficit 2
• Moderate dehydration: 6-9% fluid deficit 2
• Severe dehydration: ≥10% fluid deficit 2

Management Algorithm Based on Presentation

For Vomiting WITHOUT Red Flags (Most Common: Viral Gastroenteritis)

Step 1: Initiate Oral Rehydration Therapy

• For mild dehydration (3-5% deficit): Administer 50 mL/kg of oral rehydration solution (ORS) containing 50-90 mEq/L sodium over 2-4 hours 1, 2
• For moderate dehydration (6-9% deficit): Administer 100 mL/kg of ORS over 2-4 hours 1, 2
• Replace ongoing losses: Give 10 mL/kg ORS for each diarrheal stool and 2 mL/kg for each vomiting episode 1

Critical Technique for Vomiting Patients:

• Do NOT allow ad libitum drinking—this worsens vomiting 1
• Administer small volumes (5-10 mL) every 1-2 minutes via spoon or syringe to allow gradual rehydration without triggering vomiting reflex 1

Step 2: Consider Ondansetron for Persistent Vomiting

• Indication: Use when persistent vomiting prevents oral intake despite proper ORS technique 3, 4
• Dosing (ages 4-11 years): 4 mg oral 5
• Dosing (ages 12-17 years): 8 mg oral 5
• Parenteral dosing if unable to take oral: 0.15 mg/kg IV (maximum 4 mg) 3
• Evidence: Ondansetron reduces vomiting, facilitates ORT, and minimizes need for IV therapy and hospitalization 4

Step 3: Resume Feeding

• For breastfed infants: Continue nursing on demand without interruption 6
• For bottle-fed infants: Use full-strength, lactose-free or lactose-reduced formulas immediately upon rehydration 1, 6
• For older children: Resume normal age-appropriate diet during or immediately after rehydration 2, 6
• Early feeding improves nutritional outcomes and is as safe as delayed feeding 2

For Vomiting WITH Red Flags or Severe Dehydration

Step 1: Stop Oral Intake and Decompress Stomach

• For bilious vomiting: Stop all oral fluids/feeds and place nasogastric tube for decompression 3

Step 2: Initiate IV Fluid Resuscitation

• Administer 20 mL/kg boluses of Ringer's lactate or normal saline until pulse, perfusion, and mental status normalize 6
• For severe dehydration or shock: Switch to IV isotonic crystalloids immediately 1

Step 3: Obtain Laboratory Studies

• Measure serum creatinine, electrolytes, and blood gases to stage severity and identify complications 1
• Serum bicarbonate ≤13 mEq/L predicts failure of oral rehydration and need for prolonged IV therapy 7

Step 4: Pursue Diagnostic Workup

• Obtain appropriate imaging (abdominal X-ray, ultrasound, or CT) based on suspected surgical cause 3
• Consider surgical consultation for bilious vomiting, peritoneal signs, or suspected obstruction 3

Hospitalization Criteria

Admit patients with:

• Severe dehydration, shock, or altered mental status 6
• Inability to protect airway or ileus preventing oral intake 6
• Failed oral rehydration therapy despite adequate trial 6
• Serum bicarbonate ≤13 mEq/L (predicts need for prolonged IV therapy) 7

Critical Pitfalls to Avoid

• Do not use loperamide in children under 18 years 2
• Do not allow rapid, large-volume oral intake in vomiting patients—this triggers more vomiting 1
• Do not assume viral gastroenteritis without considering life-threatening causes, especially in infants (pyloric stenosis, malrotation, intussusception, metabolic disorders) 3
• Do not continue nephrotoxic medications or diuretics in dehydrated patients 1