What is the appropriate management for a patient presenting with acute gastroenteritis?

Management of Acute Gastroenteritis

Oral rehydration solution (ORS) is the first-line treatment for mild to moderate dehydration in acute gastroenteritis, with early refeeding and supportive care forming the cornerstone of management. 1

Initial Assessment and Hydration Status

Evaluate dehydration severity through specific clinical signs to guide therapy 1:

• Mild dehydration (3-5% fluid deficit): Slightly dry mucous membranes, normal vital signs, adequate urine output 1
• Moderate dehydration (6-9% fluid deficit): Loss of skin turgor with tenting when pinched, dry mucous membranes, decreased urine output, tachycardia 1
• Severe dehydration (≥10% fluid deficit): Severe lethargy or altered consciousness, prolonged skin tenting (>2 seconds), cool and poorly perfused extremities, decreased capillary refill, rapid deep breathing indicating acidosis 1

The most accurate assessment is acute weight change if premorbid weight is known, though prolonged skin retraction time, abnormal capillary refill, and rapid deep breathing are the most reliable clinical predictors 1.

Rehydration Protocol

Mild to Moderate Dehydration

Administer low-osmolarity ORS as first-line therapy 1, 2:

• For mild dehydration: 50 mL/kg ORS over 2-4 hours 1
• For moderate dehydration: 100 mL/kg ORS over 2-4 hours 1
• Replace ongoing losses continuously: 10 mL/kg ORS for each watery stool and 2 mL/kg for each vomiting episode 1
• Technique for vomiting patients: Start with small volumes (5-10 mL every 1-2 minutes) using a spoon or syringe, gradually increasing as tolerated 1
• Nasogastric administration may be considered for patients who cannot tolerate oral intake or refuse to drink adequately 1

Low-osmolarity ORS formulations are preferred over sports drinks, apple juice, or soft drinks, which have inappropriate osmolarity and can worsen osmotic diarrhea through high simple sugar content 1.

Severe Dehydration

Reserve intravenous rehydration for specific indications 1:

• Severe dehydration with shock or altered mental status 1
• Failure of oral rehydration therapy after 2-4 hours of appropriate ORS administration 1
• Intractable vomiting despite antiemetics 1
• Ileus (absent bowel sounds on auscultation) 1

Use isotonic fluids such as lactated Ringer's or normal saline, continuing IV therapy until pulse, perfusion, and mental status normalize, then transition to ORS to replace remaining deficit 1.

Nutritional Management

Resume age-appropriate diet during or immediately after rehydration—do not delay feeding 1:

• Continue breastfeeding in infants throughout the diarrheal episode 1
• Early refeeding reduces severity and duration of illness 1
• Avoid restrictive diets or prolonged fasting 1

Foods to avoid during acute illness 1:

• Foods high in simple sugars (soft drinks, undiluted apple juice) that exacerbate diarrhea through osmotic effects 1
• Caffeinated beverages (coffee, tea, energy drinks) that worsen symptoms through stimulation of intestinal motility 1
• High-fat foods 1

Pharmacological Management

Antiemetics

Ondansetron may be given to children >4 years and adolescents to facilitate oral rehydration when vomiting is significant 1, 3:

• Enhances compliance with ORT and decreases hospitalization rates 3
• Allows improved tolerance of ORS when used appropriately 4

Antimotility Agents

Loperamide is absolutely contraindicated in children <18 years with acute diarrhea 1:

• Serious adverse events including ileus and deaths have been reported 1
• May be given to immunocompetent adults with acute watery diarrhea once adequately hydrated 1
• Never use in cases of bloody diarrhea 1

Probiotics and Zinc

• Probiotics may reduce symptom severity and duration in both adults and children 1
• Zinc supplementation reduces diarrhea duration in children 6 months to 5 years of age in areas with high zinc deficiency prevalence or in children with signs of malnutrition 1

Antimicrobial Therapy

Antimicrobial agents have limited usefulness since viral agents are the predominant cause 1:

• Consider only in specific cases: bloody diarrhea with fever, recent antibiotic use (test for Clostridioides difficile), exposure to certain pathogens, recent foreign travel, or immunodeficiency 1, 5
• Do not use adsorbents, antisecretory drugs, or toxin binders—they do not demonstrate effectiveness in reducing diarrhea volume or duration 1

Infection Control Measures

Implement strict infection control to prevent transmission 1:

• Practice proper hand hygiene after using toilet or changing diapers, before and after food preparation, before eating, and after handling soiled items 1
• Use gloves and gowns when caring for people with diarrhea 1
• Clean and disinfect contaminated surfaces promptly 1
• Separate ill persons from well persons until at least 2 days after symptom resolution 1

Admission Criteria

Hospitalize patients with the following high-risk features 1:

• Severe dehydration (≥10% fluid deficit) requiring IV therapy 1
• Signs of shock or persistent tachycardia/hypotension despite initial fluid resuscitation 1
• Failure of oral rehydration therapy 1
• Altered mental status 1
• Intractable vomiting despite antiemetics 1
• Significant comorbidities increasing risk of complications 1

Lower thresholds for admission apply to 1:

• Elderly patients (≥65 years) due to higher hospitalization and mortality rates 1
• Immunocompromised patients (on immunosuppressive therapy, HIV-infected, transplant recipients, malignancy) 1
• Infants <3 months given higher risk of severe dehydration and complications 1

Critical Red Flags Requiring Immediate Evaluation

Seek immediate medical attention for 1:

• Bloody stools with fever and systemic toxicity (may indicate Salmonella, Shigella, or enterohemorrhagic E. coli) 1
• Symptoms persisting beyond 5-7 days (typical viral gastroenteritis resolves within this timeframe) 6
• Severe abdominal pain disproportionate to examination findings or suggesting surgical abdomen 1
• Signs of hemolytic uremic syndrome in bloody diarrhea cases 1

Common Pitfalls to Avoid

• Do not delay rehydration while awaiting diagnostic testing—initiate promptly 1
• Do not use inappropriate fluids like apple juice or sports drinks as primary rehydration solutions for moderate to severe dehydration 1
• Do not administer antimotility drugs to children or in cases of bloody diarrhea 1
• Do not unnecessarily restrict diet during or after rehydration 1
• Do not underestimate dehydration in elderly patients who may not manifest classic signs 1
• Do not use metoclopramide—it has no role in gastroenteritis management and may worsen outcomes 1