What is the approach to managing vomiting in pediatric patients?

Approach to Vomiting in Pediatrics

Immediate Assessment: Identify Life-Threatening Causes First

Begin by rapidly assessing for red flag signs that indicate surgical emergencies or critical illness: bilious or bloody vomiting, altered mental status, toxic/septic appearance, severe dehydration, bent-over posture, or inconsolable crying. 1

• Check vital signs immediately, focusing on blood pressure, respiratory pattern, and capillary refill time—abnormal capillary refill, abnormal skin turgor, and abnormal respiratory pattern are the three most useful predictors of ≥5% dehydration 2
• Bilious vomiting mandates immediate cessation of oral intake, nasogastric decompression, and surgical consultation for possible malrotation with volvulus or intestinal obstruction 1
• Bloody vomitus requires evaluation for upper GI bleeding or severe gastritis 1

Hydration Status Assessment

Classify dehydration severity clinically to guide rehydration strategy:

• Mild dehydration (3-5% fluid deficit): Slightly decreased skin turgor, dry mucous membranes, normal vital signs 3, 4
• Moderate dehydration (6-9% fluid deficit): Decreased skin turgor, sunken eyes, decreased urine output, mild tachycardia 3, 4
• Severe dehydration (≥10% fluid deficit): Markedly decreased skin turgor, sunken fontanelle (infants), lethargy, weak pulse, prolonged capillary refill >3 seconds 3, 4

Common pitfall: Serum bicarbonate <13 mEq/L predicts failure of oral rehydration—these children typically require IV therapy and admission 5

Rehydration Protocol Based on Severity

Mild to Moderate Dehydration (Most Common Scenario)

Initiate oral rehydration solution (ORS) containing 50-90 mEq/L sodium using small, frequent volumes to overcome vomiting:

• Administer 5 mL every 1-2 minutes via spoon or syringe under close supervision—this gradual approach succeeds in >90% of vomiting children 6
• For mild dehydration: Give 50 mL/kg ORS over 2-4 hours 3, 4
• For moderate dehydration: Give 100 mL/kg ORS over 2-4 hours 3, 4
• Replace ongoing losses with 10 mL/kg ORS for each diarrheal stool and 2 mL/kg for each vomiting episode 7

Critical pitfall to avoid: Never allow ad libitum drinking from a cup or bottle in vomiting children—this invariably triggers more vomiting. Controlled, small-volume administration is essential 6, 7

Severe Dehydration or Shock

Immediately initiate IV rehydration with 20 mL/kg boluses of Ringer's lactate or normal saline until pulse, perfusion, and mental status normalize. 3, 4

• Rapid IV rehydration over 1-2 hours corrects dehydration and resolves vomiting in 72% of children with moderate dehydration 5
• After stabilization, transition to oral rehydration if the child tolerates small volumes without vomiting 5

Antiemetic Use: Ondansetron

Ondansetron is indicated when persistent vomiting prevents oral intake, reducing vomiting episodes, improving oral rehydration success, and decreasing hospital admissions:

• Dosing for children 4-11 years: 4 mg orally, with subsequent 4 mg doses at 4 and 8 hours after the first dose 8
• Dosing for children 12-17 years: 8 mg orally, with a subsequent 8 mg dose 8 hours after the first dose 8
• Parenteral dosing: 0.15 mg/kg IV (maximum 4 mg) 1
• Single-dose ondansetron reduces recurrent vomiting, need for IV fluids, and hospital admissions in acute gastroenteritis 9, 2

Important caveat: Ondansetron is FDA-approved only for chemotherapy-induced nausea in children ≥4 years, but has strong evidence supporting "off-label/on-evidence" use in acute gastroenteritis 8, 9

Nutritional Management During Illness

Continue feeding throughout rehydration without "resting the bowel"—early nutrition improves outcomes:

• Breastfed infants: Continue nursing on demand without interruption 6, 3, 4
• Bottle-fed infants: Resume full-strength, lactose-free or lactose-reduced formula immediately upon rehydration 6, 3, 4
• Older children: Resume age-appropriate diet with starches, cereals, yogurt, fruits, and vegetables; avoid foods high in simple sugars and fats 6

Common pitfall: Presence of reducing substances in stool alone does NOT indicate lactose intolerance—only clinical worsening of diarrhea upon lactose reintroduction warrants lactose restriction 6

When to Consider Antibiotics

Antibiotics are NOT routinely indicated for vomiting or acute watery diarrhea, but consider when:

• Dysentery (bloody diarrhea) is present, indicating invasive bacterial enteritis 6, 3, 4
• High fever accompanies diarrhea 6
• Watery diarrhea persists >5 days 6
• Stool cultures or epidemic setting indicate a specific treatable pathogen 6

Hospitalization Criteria

Admit patients with:

• Severe dehydration, shock, or altered mental status 3
• Intractable vomiting despite ondansetron and small-volume ORS trial 6
• Serum bicarbonate ≤13 mEq/L (predicts oral rehydration failure) 5
• Bilious vomiting requiring surgical evaluation 1
• Inability to tolerate oral fluids after rapid IV rehydration 5

Parental Instructions for Home Management

Educate caregivers to return immediately if the child develops:

• Irritability or lethargy 6
• Decreased urine output 6
• Intractable vomiting 6
• Persistent diarrhea 6

Provide a 24-hour supply of ORS at discharge and emphasize that ORS should be a household staple, like acetaminophen 6