What is the management approach for acute vomiting?

Management of Acute Vomiting

Begin oral rehydration therapy immediately with small, frequent volumes (5 mL every minute) using a spoon or syringe, as this approach corrects dehydration and simultaneously reduces vomiting frequency in most patients. 1

Initial Assessment: Determine Hydration Status and Exclude Red Flags

Assess dehydration severity clinically by examining skin turgor, mental status, mucous membrane moisture, capillary refill, and vital signs 1, 2:

• Mild dehydration (3-5% deficit): Increased thirst, slightly dry mucous membranes 2
• Moderate dehydration (6-9% deficit): Loss of skin turgor, dry mucous membranes 2
• Severe dehydration (≥10% deficit): Severe lethargy, prolonged skin tenting, cool extremities, decreased capillary refill—this is a medical emergency 1, 2

Rule out life-threatening conditions immediately before assuming benign gastroenteritis 2:

• Meningitis/sepsis: altered consciousness, severe lethargy, irritability 2
• Pneumonia: respiratory distress, cyanosis, hypoxia 2
• Surgical emergencies: bilious vomiting, severe abdominal pain, bent-over posture 2, 3
• Urinary tract infection: common cause of fever with vomiting in children 2

Fluid Management Algorithm

For Mild to Moderate Dehydration (No Shock)

Start oral rehydration solution (ORS) immediately 1, 4:

• Mild dehydration: Give 50 mL/kg ORS over 2-4 hours 1
• Moderate dehydration: Give 100 mL/kg ORS over 2-4 hours 1
• Technique: Use teaspoon, syringe, or medicine dropper to give small volumes initially (5 mL every minute), then gradually increase as tolerated 1
• Replace ongoing losses: Give 2 mL/kg for each vomiting episode and 10 mL/kg for each watery stool 1

Reassess hydration status after 2-4 hours 1:

• If rehydrated: proceed to maintenance phase
• If still dehydrated: reestimate deficit and restart rehydration

For Severe Dehydration (≥10% Deficit or Shock)

Initiate IV rehydration immediately with isotonic crystalloid (Ringer's lactate or normal saline) 1, 4:

• Give 20 mL/kg boluses until pulse, perfusion, and mental status normalize 1
• May require two IV lines or alternate access (venous cutdown, femoral vein, intraosseous) 1
• Transition to oral rehydration once consciousness returns to replace remaining deficit 1, 4

Antiemetic Therapy: When and What to Use

Children

Ondansetron is indicated ONLY for children >4 years with vomiting that prevents oral rehydration 5:

• Dose: 0.2 mg/kg oral (maximum 4 mg) or 0.15 mg/kg IV/IM (maximum 4 mg) 3
• Purpose: Facilitate oral rehydration therapy, not routine symptom control 5
• Do NOT use in children <4 years due to insufficient safety data 5
• Warning: May increase stool volume/diarrhea but benefit outweighs this side effect 5

Never give these medications to children 4, 5:

• Loperamide or antimotility drugs in children <18 years 4, 5
• Prochlorperazine in children <20 pounds or <2 years, or in dehydrated children 6
• Promethazine has respiratory depression risk in young children 7

Adults

Ondansetron is the preferred first-line antiemetic due to superior efficacy and safety (no sedation or extrapyramidal effects) 5

Critical caveat: Antiemetics are NOT a substitute for fluid replacement—ensure adequate hydration first or concurrently 5

Nutritional Management

Resume age-appropriate diet immediately upon rehydration 1, 4:

• Infants: Continue breastfeeding on demand throughout illness 1, 4
• Bottle-fed infants: Give full-strength formula immediately after rehydration 1
• Older children: Resume usual diet with starches, cereals, yogurt, fruits, vegetables 1
• Avoid: Foods high in simple sugars (soft drinks, undiluted apple juice) and fats 1, 4

Do not withhold food or use restrictive diets—early refeeding improves outcomes 4

Medications to Avoid

Never use these agents as they shift focus from appropriate fluid therapy and cause complications 1, 4:

• Antimotility agents (loperamide, diphenoxylate) 4
• Adsorbents, antisecretory drugs, toxin binders 4
• Antibiotics (unless specific indications: dysentery, high fever, >5 days duration, positive cultures) 1

Indications for Hospital Admission

Send to hospital immediately if any of these present 2:

• Respiratory distress or cyanosis
• Altered consciousness or severe lethargy
• Intractable vomiting (unable to tolerate oral fluids after rapid IV rehydration)
• Signs of septicemia
• Bilious or bloody vomiting
• Serum bicarbonate ≤13 mEq/L (predicts failure of outpatient management) 8

Parent Education and Follow-Up

Instruct caregivers to return immediately if 1, 2:

• Child becomes irritable, lethargic, or has altered consciousness
• Decreased urine output develops
• Intractable vomiting continues
• Persistent diarrhea worsens

Common Pitfalls to Avoid

• Assuming viral gastroenteritis without excluding serious causes: Meningitis, pneumonia, UTI, and surgical emergencies can present identically 2
• Using inappropriate fluids: Sports drinks or apple juice are not adequate for moderate-severe dehydration 4
• Delaying oral rehydration: Early aggressive ORS prevents progression to severe dehydration 2, 4
• Relying on clinical appearance alone: Many children with serious bacterial infections may appear well initially 2
• Giving antimotility drugs: These cause serious complications and are contraindicated 4, 5
• Withholding food: Restrictive diets worsen outcomes 4