What is the treatment for acute gastroenteritis characterized by vomiting and diarrhea?

Treatment of Vomiting and Diarrhea

Oral rehydration solution (ORS) is the first-line treatment for acute gastroenteritis with vomiting and diarrhea, regardless of age, and should be initiated immediately using small, frequent volumes (5-10 mL every 1-2 minutes) to successfully rehydrate over 90% of patients without antiemetics. 1, 2

Initial Assessment and Categorization

Assess dehydration severity through clinical examination focusing on:

• Skin turgor and capillary refill time 1, 2
• Mental status and level of consciousness 1
• Mucous membrane moisture 1, 2
• Vital signs including pulse and perfusion 1

Categorize dehydration as:

• Mild (3-5% fluid deficit): Minimal clinical signs 1, 2
• Moderate (6-9% fluid deficit): Dry mucous membranes, decreased skin turgor 1, 2
• Severe (≥10% fluid deficit): Altered mental status, prolonged capillary refill, signs of shock 1

Rehydration Protocol by Severity

Mild to Moderate Dehydration (3-9%)

Start ORS immediately using the following technique:

• Administer 5-10 mL every 1-2 minutes using a teaspoon, syringe, or medicine dropper 1, 2, 3
• Gradually increase volume as tolerated without triggering vomiting 1, 2
• Total volume: 50 mL/kg for mild (3-5%) or 100 mL/kg for moderate (6-9%) dehydration over 2-4 hours 1, 2
• Reassess hydration status after 2-4 hours 1, 2

Critical point: The small, frequent volume technique is essential—giving too much too quickly will trigger more vomiting and lead to unnecessary IV therapy. 2

Severe Dehydration (≥10%)

This is a medical emergency requiring immediate IV rehydration:

• Administer 20 mL/kg boluses of lactated Ringer's or normal saline 1
• Continue IV therapy until pulse, perfusion, and mental status normalize 1
• Once patient awakens and has no aspiration risk, transition to ORS for remaining deficit 1, 2

Ongoing Loss Replacement

Replace continuing losses throughout treatment:

• 10 mL/kg of ORS for each watery stool 1, 2
• 2 mL/kg of ORS for each vomiting episode 1, 2
• Continue replacement until diarrhea and vomiting resolve 1, 2

Nutritional Management

Resume feeding early—do not withhold food:

• Continue breastfeeding on demand throughout the illness 1, 2, 3
• Resume age-appropriate normal diet during or immediately after rehydration is complete 1, 2, 3
• For bottle-fed infants, use full-strength formula immediately upon rehydration 1, 2

Avoid restrictive diets or prolonged fasting—early refeeding reduces illness severity and duration. 2, 3

Pharmacological Adjuncts (Once Adequately Hydrated)

Antiemetics

Ondansetron may be given to children >4 years and adults to facilitate oral rehydration when vomiting is significant. 1, 2

Antimotility Agents

Loperamide has strict age and clinical restrictions:

• NEVER give to children <18 years with acute diarrhea 1, 2, 4
• May be given to immunocompetent adults with acute watery diarrhea once adequately hydrated 1, 2, 4
• AVOID in bloody diarrhea, fever, or suspected inflammatory diarrhea due to risk of toxic megacolon 1, 2, 4

Probiotics

May be offered to reduce symptom severity and duration in immunocompetent patients. 1, 2

Zinc Supplementation

Administer to children 6 months to 5 years in areas with high zinc deficiency prevalence or signs of malnutrition. 1, 2

Critical Pitfalls to Avoid

Do not delay rehydration while awaiting diagnostic testing—begin ORS immediately. 2

Do not use sports drinks, apple juice, or other high-sugar beverages as primary rehydration—these worsen diarrhea through osmotic effects. 2

Do not give antimotility drugs to children or in cases of bloody diarrhea. 1, 2, 4

Do not restrict diet unnecessarily—early refeeding is beneficial. 1, 2, 3

Do not underestimate dehydration in elderly patients who may not show classic signs. 2

Do not use caffeinated beverages for hydration—caffeine stimulates intestinal motility and worsens diarrhea. 2

When to Seek Emergency Care

Immediate medical evaluation is required for:

• Signs of severe dehydration or shock 1, 2
• Altered mental status or severe lethargy 1, 2
• Failure of oral rehydration therapy despite proper technique 1, 2
• Bloody diarrhea with fever 1, 2
• Absent bowel sounds (ileus) 1, 2
• Intractable vomiting despite small-volume ORS and antiemetics 2

Infection Control

Practice rigorous hand hygiene:

• After toilet use or diaper changes 1, 2
• Before and after food preparation 1, 2
• Use soap and water or alcohol-based sanitizers 1, 2
• Wear gloves and gowns when caring for patients with diarrhea 1, 2