What is the appropriate treatment approach for a patient with suspected food poisoning versus acute gastroenteritis?

Treatment Approach: Food Poisoning vs Acute Gastroenteritis

The Distinction is Clinically Irrelevant for Treatment Purposes

The treatment approach for food poisoning and acute gastroenteritis is identical because food poisoning is simply one subset of acute gastroenteritis—both require the same evidence-based management focused on rehydration, supportive care, and selective antimicrobial therapy based on specific clinical criteria rather than the source of infection. 1, 2

Core Treatment Algorithm

Step 1: Assess Hydration Status and Severity

Evaluate for clinical signs of dehydration 2:

• Mild dehydration (3-5%): Slightly dry mucous membranes, normal vital signs
• Moderate dehydration (6-9%): Decreased skin turgor, tachycardia, reduced urine output
• Severe dehydration (≥10%): Altered mental status, hypotension, poor perfusion, shock

Step 2: Initiate Rehydration Based on Severity

For mild to moderate dehydration:

• Reduced osmolarity oral rehydration solution (ORS) is first-line therapy 1, 2
• Administer 100 mL/kg over 2-4 hours for moderate dehydration 2
• Replace ongoing losses: 10 mL/kg for each watery stool, 2 mL/kg for each vomiting episode 2
• In adults without severe dehydration, glucose-containing drinks or electrolyte-rich soups guided by thirst are sufficient 3

For severe dehydration, shock, or altered mental status:

• Isotonic intravenous fluids (lactated Ringer's or normal saline) are mandatory 1, 2
• Continue IV therapy until pulse, perfusion, and mental status normalize 1
• Transition to ORS once patient improves 2

Step 3: Determine Need for Antimicrobial Therapy

Do NOT give empiric antibiotics for typical watery diarrhea 1, 2

DO give empiric antimicrobials ONLY for these specific scenarios 1:

Bloody diarrhea with:

• Infants <3 months of age with suspected bacterial etiology 1
• Fever documented in medical setting + abdominal pain + bacillary dysentery (frequent scant bloody stools, fever, cramps, tenesmus) presumptively due to Shigella 1
• Recent international travel with temperature ≥38.5°C or signs of sepsis 1
• Immunocompromised patients with severe illness 1

Empiric antibiotic choices 1:

• Adults: Ciprofloxacin or azithromycin (based on local susceptibility and travel history)
• Children: Azithromycin (or third-generation cephalosporin for infants <3 months or neurologic involvement)

Critical exception—AVOID antibiotics if STEC/Shiga toxin-producing E. coli suspected (can precipitate hemolytic uremic syndrome) 1

Step 4: Adjunctive Pharmacological Management

Antiemetics:

• Ondansetron may be given to children >4 years and adults with significant vomiting to facilitate oral rehydration 2, 4
• This reduces hospitalization rates and improves ORS tolerance 4

Antimotility agents:

• Loperamide 2 mg may be given to immunocompetent adults with watery diarrhea once adequately hydrated 2, 3
• NEVER give loperamide to children <18 years, or anyone with bloody diarrhea or high fever 1, 2, 3

Probiotics:

• May reduce symptom severity and duration in both adults and children 2

Step 5: Nutritional Management

• Resume age-appropriate diet immediately during or after rehydration—do not restrict diet 2, 3
• Continue breastfeeding throughout illness in infants 2
• Avoid foods high in simple sugars (soft drinks, undiluted apple juice), fatty/spicy foods, and caffeine 2, 3

Common Pitfalls to Avoid

Critical errors that worsen outcomes:

1. Delaying rehydration while awaiting diagnostic tests—start ORS immediately 2, 3
2. Using sports drinks or apple juice as primary rehydration for moderate-severe dehydration—these lack appropriate electrolyte composition 2, 3
3. Giving antimotility drugs to children or patients with bloody diarrhea—can cause toxic megacolon or worsen STEC complications 1, 2
4. Prescribing antibiotics for typical watery diarrhea—70% of cases are viral and antibiotics provide no benefit 1, 2
5. Unnecessarily restricting diet during recovery—early refeeding reduces illness duration 2, 3
6. Underestimating dehydration in elderly patients—they have higher mortality and may not show classic signs 2

Admission Criteria

Hospitalize patients with 2:

• Severe dehydration (≥10% fluid deficit)
• Signs of shock or persistent hypotension despite initial resuscitation
• Altered mental status
• Intractable vomiting despite antiemetics
• Failure of oral rehydration therapy
• Age <3 months (consider carefully)
• Age ≥65 years with moderate dehydration (lower threshold)
• Immunocompromised status
• Bloody diarrhea with fever and systemic toxicity (monitor for hemolytic uremic syndrome)

Infection Control Measures

Essential to prevent transmission 2, 3:

• Hand hygiene after toilet use, before food preparation/eating, after handling soiled items
• Use gloves and gowns when caring for ill persons
• Clean and disinfect contaminated surfaces promptly
• Separate ill persons from well persons until at least 2 days after symptom resolution