Gastroenteritis: Signs and Treatment
The mainstay of treatment for gastroenteritis is oral rehydration therapy, with intravenous fluids reserved for severe dehydration, shock, altered mental status, or failure of oral rehydration therapy. 1
Clinical Presentation
Signs and Symptoms
Gastrointestinal manifestations:
- Diarrhea (watery, bloody, mucous, or purulent)
- Vomiting
- Abdominal pain and cramps
- Tenesmus (in dysenteric presentations)
Systemic manifestations:
- Fever
- Headache
- Myalgias
- Lethargy
Assessment of Dehydration
Dehydration severity guides treatment approach:
Mild dehydration (3-5% fluid deficit):
- Increased thirst
- Slightly dry mucous membranes
- Normal vital signs
Moderate dehydration (6-9% fluid deficit):
- Loss of skin turgor
- Skin tenting when pinched
- Dry mucous membranes
- Tachycardia
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 (acidosis)
- Hypotension
Treatment Approach
1. Rehydration Therapy
Mild to Moderate Dehydration:
- Oral rehydration solution (ORS) is first-line therapy 1
- Dose: 50-100 mL/kg over 3-4 hours for children
- Adults: 2-4 L of ORS
- Replace ongoing losses: 60-120 mL for each diarrheal stool or vomiting episode
Severe Dehydration:
- Intravenous fluids (isotonic crystalloids such as lactated Ringer's or normal saline) 1
- Continue until pulse, perfusion, and mental status normalize
- Once stabilized, transition to oral rehydration
If vomiting prevents oral intake:
- Consider nasogastric administration of ORS 1
- For children >4 years with significant vomiting, ondansetron may facilitate oral rehydration 1
2. Antimicrobial Therapy
Antimicrobial therapy is NOT routinely recommended for most cases of gastroenteritis 1
Empiric antimicrobial therapy is indicated only in specific situations:
- Infants <3 months with suspected bacterial etiology
- Immunocompromised patients with severe illness and bloody diarrhea
- Patients with fever >38.5°C, recent international travel, and signs of sepsis
- Confirmed bacterial pathogens requiring treatment
When indicated in adults, use either:
- Fluoroquinolone (e.g., ciprofloxacin)
- Azithromycin (based on local susceptibility patterns)
3. Symptomatic Treatment
Antimotility agents (e.g., loperamide):
- Should NOT be given to children <18 years 1, 2
- May be used cautiously in adults with watery diarrhea
- Contraindicated in inflammatory diarrhea, bloody diarrhea, or fever 1, 2
- Avoid in elderly due to risk of ileus 3
Bismuth subsalicylate:
- May provide symptomatic relief in adults 3
- Dosage: 2 tablets (262 mg each) or 30 ml liquid every 4-6 hours
- Maximum: 8 tablets or 120 ml per 24 hours
4. Nutritional Management
- Early refeeding is recommended once rehydration is initiated
- No need for prolonged fasting or "bowel rest"
- Breastfeeding should continue throughout illness
- Temporarily avoid dairy products if they worsen symptoms 3
- BRAT diet (bananas, rice, applesauce, toast) may be helpful but evidence is limited 1
Special Considerations
Children
- Higher risk of dehydration due to:
- Higher body surface-to-weight ratio
- Higher metabolic rate
- Dependence on others for fluid intake 1
- Oral rehydration is as effective as IV rehydration for preventing hospitalization 4
Elderly
- Higher risk for severe dehydration and electrolyte imbalances
- Monitor closely for signs of dehydration (dry mouth, decreased urination, dizziness, confusion) 3
- Patients on anticoagulation require special attention to medication interactions 3
Prevention
- Handwashing is crucial to prevent transmission
- Thorough cleaning of environmental surfaces
- Proper food handling and preparation
Common Pitfalls to Avoid
- Overuse of antimotility agents in children or in inflammatory diarrhea
- Unnecessary use of antibiotics for viral gastroenteritis
- Delayed refeeding after initial rehydration
- Relying on sports drinks instead of proper oral rehydration solutions
- Underestimating dehydration in vulnerable populations (very young, elderly)
Remember that most cases of gastroenteritis are self-limiting and will resolve within a few days with proper hydration and supportive care.