What is the treatment for a 50-year-old patient with suspected food poisoning?

Treatment of Suspected Food Poisoning in a 50-Year-Old Adult

For a 50-year-old with suspected food poisoning, the primary treatment is aggressive oral rehydration with oral rehydration solution (ORS), and antibiotics should only be given if there is bloody diarrhea with fever—otherwise, supportive care alone is appropriate. 1

Initial Assessment

When evaluating this patient, focus on these specific clinical features:

• Hydration status: Look for increased thirst, dry mucous membranes, loss of skin turgor, and urine output 2
• Stool characteristics: Document frequency, volume, and critically—the presence of blood or mucus 1, 2
• Fever: Temperature >38°C suggests bacterial infection 1
• Timing: Symptoms within hours to one day of eating suggest food poisoning; if severe GI symptoms occurred within hours and mushrooms were consumed, consider amatoxin poisoning 1, 3
• Ability to tolerate oral fluids: This determines whether outpatient management is feasible 2

Rehydration Protocol (The Cornerstone of Treatment)

Oral rehydration is the primary treatment for food poisoning. 1

• For mild dehydration: Give 50-100 mL of ORS after each loose stool 1, 2
• For moderate dehydration: Administer 100 mL/kg ORS over 2-4 hours 2
• Reassess after 2-4 hours: Continue rehydration if still dehydrated 2
• Increase normal fluid intake: Encourage locally available fluids like soup, rice water, or cereal-based gruels 1

The 2017 IDSA guidelines emphasize that most cases of infectious diarrhea are self-limited and require only supportive care with hydration. 1

When to Use Antibiotics (Critical Decision Point)

Do NOT give antibiotics routinely. Antibiotics are indicated only in specific circumstances: 1

Give antibiotics if:

• Bloody diarrhea (dysentery) PLUS fever 1, 2
• Severe systemic symptoms (high fever, severe abdominal pain, signs of sepsis) 1

Antibiotic choice:

• First-line: Azithromycin 500 mg daily for 3 days (covers Campylobacter, Shigella, Salmonella) 1
• Alternative: Ciprofloxacin 500 mg twice daily for 3 days, but avoid if Shigella is suspected with ciprofloxacin MIC ≥0.12 μg/mL 1

Obtain stool culture BEFORE starting antibiotics if dysentery is present 1, 2

Medications to AVOID

Do not use loperamide (Imodium) if there is any fever or bloody diarrhea, as this increases the risk of toxic megacolon and can worsen invasive bacterial infections. 2, 4 The FDA label for loperamide states it should not be used when inhibition of peristalsis should be avoided. 4

Special Consideration: Mushroom Poisoning

If the patient ate wild mushrooms and has severe GI symptoms (nausea, vomiting, diarrhea, cramping) within hours to one day:

• This is a medical emergency requiring immediate ED referral 1, 3
• If presenting early: Consider gastric lavage and activated charcoal 1 g/kg via nasogastric tube 3, 5
• Aggressive IV fluid resuscitation is essential 3
• Antidote therapy: Penicillin G 300,000-1 million units/kg/day IV PLUS silymarin 30-40 mg/kg/day 1, 3
• List for liver transplantation immediately, as this is often the only lifesaving option 1, 3

Red Flags Requiring Emergency Department Evaluation

Refer immediately if: 1, 2

• Inability to tolerate oral fluids
• Signs of severe dehydration (prolonged skin tenting, severe lethargy, hypotension)
• Altered mental status
• Suspected mushroom ingestion
• Immunocompromised, elderly with comorbidities, or signs of sepsis 6

Monitoring and Follow-Up

• Reassess after 2-4 hours to ensure adequate response to rehydration 2
• If symptoms worsen despite treatment: Consider C. difficile if recent healthcare exposure or antibiotics, and obtain stool testing 1
• Most cases resolve within 48 hours with supportive care alone 4

Common Pitfalls to Avoid

• Don't give antibiotics empirically without bloody diarrhea and fever—this promotes resistance and doesn't improve outcomes in viral or toxin-mediated food poisoning 1
• Don't use antimotility agents with fever or bloody stools—this can cause serious complications 2, 4
• Don't underestimate dehydration—aggressive rehydration is more important than any other intervention 1, 2
• Don't miss mushroom poisoning—always ask specifically about wild mushroom consumption 1, 3