What is the management for acute gastroenteritis (GE) in an adult and a 12-year-old that started yesterday?

Management of Acute Gastroenteritis in Adults and 12-Year-Olds

The primary management for acute gastroenteritis in both adults and 12-year-olds is oral rehydration therapy (ORT) with appropriate oral rehydration solution (ORS), with resumption of normal diet as soon as possible after rehydration. 1

Assessment of Dehydration

• Evaluate hydration status through physical examination looking for specific signs including decreased skin turgor, dry mucous membranes, sunken eyes, altered mental status, tachycardia, and decreased urine output 1
• Categorize dehydration as:
  • Mild: <4% body weight lost
  • Moderate: 4-6% body weight lost
  • Severe: >6% body weight lost 1
• The three most useful predictors of significant dehydration (≥5%) are abnormal capillary refill, abnormal skin turgor, and abnormal respiratory pattern 2

Rehydration Therapy

For Mild to Moderate Dehydration

• Provide oral rehydration solution (ORS) as first-line therapy:
  • For the 12-year-old: 50-100 mL/kg over 3-4 hours
  • For adults: 2-4 L of ORS 1, 3
• Use commercially available low-osmolarity ORS (e.g., Pedialyte, CeraLyte) and avoid apple juice, sports drinks, and soft drinks as they are not appropriate for rehydration 1, 4
• If the 12-year-old refuses ORS, nasogastric administration may be considered 3, 1

For Severe Dehydration

• Administer isotonic intravenous fluids (lactated Ringer's or normal saline) at 20 mL/kg over 30 minutes 1, 3
• Continue IV rehydration until pulse, perfusion, and mental status normalize 3, 1
• After initial stabilization, the remaining deficit can be replaced using ORS 3

Maintenance and Ongoing Losses

• Replace ongoing losses with ORS until diarrhea and vomiting resolve:
  • For the 12-year-old: 120-240 mL ORS for each diarrheal stool/vomiting episode
  • For adults: ad libitum intake up to ~2 L/day 1, 3
• Once rehydrated, maintain normal fluid intake and resume regular diet 3, 1

Nutritional Management

• Resume age-appropriate diet during or immediately after rehydration 3, 1
• Avoid fasting or withholding food as this does not improve outcomes and may prolong illness 1, 4

Pharmacological Management

For the 12-Year-Old

• Ondansetron may be given to facilitate oral rehydration if significant vomiting is present, at a dose of 0.15 mg/kg 3, 1
• Antimotility drugs like loperamide should NOT be given to children under 18 years of age with acute diarrhea 3, 5

For Adults

• Loperamide may be given for acute watery diarrhea at a dose of 4 mg initially, followed by 2 mg after each loose stool (maximum 16 mg/day) 3, 1, 5
• Avoid loperamide in cases of inflammatory diarrhea, diarrhea with fever, or suspected toxic megacolon 3, 5
• Antiemetics may be considered once the patient is adequately hydrated 3

Probiotics and Supplements

• Probiotic preparations may be offered to reduce symptom severity and duration in both adults and children 3
• Zinc supplementation is only recommended for children 6 months to 5 years of age in countries with high prevalence of zinc deficiency or with signs of malnutrition 3

Prevention Measures

• Practice proper hand hygiene after using toilet, changing diapers, before/after food preparation, and after handling animals 3
• Use infection control measures including gloves, gowns, and hand hygiene with soap and water or alcohol-based sanitizers when caring for patients with diarrhea 3

Important Caveats

• Avoid using antimotility agents in children under 18 years, as this can lead to complications 3, 5
• Recognize that most cases of acute gastroenteritis are self-limiting and viral in nature, requiring primarily supportive care 4, 6
• Seek medical attention if there are signs of severe dehydration, bloody diarrhea, persistent high fever, or worsening symptoms despite appropriate home management 4, 2