What are the symptoms and treatment options for food poisoning?

Symptoms of Food Poisoning

Food poisoning typically presents with nausea, vomiting, diarrhea (watery or bloody), abdominal pain/cramping, and fever, with symptom onset ranging from 1 hour to several days after consuming contaminated food. 1, 2

Core Clinical Presentation

The hallmark symptoms include:

• Gastrointestinal symptoms: Diarrhea (increased frequency >3 stools/day with decreased consistency), nausea, vomiting, and abdominal cramps are the most common manifestations 1, 3
• Systemic symptoms: Fever, headache, myalgia (muscle aches), arthralgias (joint pain), and general malaise frequently accompany the GI symptoms 2, 3
• Dehydration signs: Look specifically for decreased skin turgor, dry mucous membranes, decreased urine output, tachycardia, and hypotension indicating hypovolemia 1

Timing and Duration

• Incubation period: Symptoms may begin within 1-4 hours (toxin-mediated from Staphylococcus aureus, Bacillus cereus) or be delayed 12-72 hours (infectious causes like Salmonella, Campylobacter) 1
• Duration: Most foodborne illnesses are self-limiting, lasting from a few hours to several days, though some persist beyond 14 days 1, 3

Red Flag Symptoms Requiring Immediate Evaluation

Perform thorough clinical evaluation when any of these features are present:

• Bloody diarrhea (suggests invasive pathogens like Shigella, Campylobacter, or Shiga toxin-producing E. coli) 1, 4
• High fever (>38.5°C/101.3°F) indicating systemic infection 1, 4
• Profuse watery diarrhea causing severe dehydration 1
• Symptoms in high-risk populations: infants, elderly, immunocompromised patients (HIV/AIDS, neutropenia, transplant recipients, cancer patients) 1, 4
• Neurological symptoms: Descending paralysis, blurred vision, diplopia, difficulty swallowing (suggests botulism) 1

Pathogen-Specific Symptom Patterns

Toxin-Mediated (Rapid Onset: 1-6 hours)

• Staphylococcus aureus, Bacillus cereus: Abrupt onset of nausea and vomiting within 1-6 hours, minimal fever, resolves in 24-48 hours 1

Viral Gastroenteritis (12-48 hours)

• Norovirus: Vomiting predominates over diarrhea, low-grade fever, myalgia; symptoms last 12-72 hours in immunocompetent hosts 1

Bacterial Invasion (1-3 days)

• Campylobacter: Bloody diarrhea, severe abdominal cramps, fever 1, 4
• Salmonella: Diarrhea, fever, abdominal cramps; may cause bacteremia in high-risk patients 1, 4
• Shigella: Bloody diarrhea, high fever, tenesmus 1, 4

Parasitic (Days to weeks)

• Giardia, Cryptosporidium: Prolonged watery diarrhea, weight loss, malabsorption 1

Critical History to Obtain

When evaluating suspected food poisoning, specifically ask about:

• Food exposure: Raw/undercooked meat, raw seafood, unpasteurized dairy, eggs 1
• Timing: When symptoms began relative to food consumption 1
• Stool characteristics: Frequency, volume, presence of blood or mucus 1
• Travel history: Recent travel to endemic areas 1
• Outbreak context: Whether others who ate the same food are ill 1
• Immune status: HIV, cancer therapy, transplant, chronic steroids 1, 4

Treatment Approach

Immediate Management Priority

Rehydration is the cornerstone of treatment, using oral rehydration solution (ORS) for mild-moderate dehydration and IV fluids for severe dehydration, shock, or altered mental status. 4

When Antibiotics Are Indicated

• Severe illness: High fever, bloody diarrhea, or systemic toxicity 4
• Immunocompromised patients: Neutropenia, HIV/AIDS, transplant recipients 4
• First-line empiric antibiotic: Azithromycin 500 mg once daily for 3 days (covers Campylobacter and Shigella effectively) 4

Critical Contraindications

• Never use antimotility agents (loperamide) in patients with bloody diarrhea, fever, or suspected Shiga toxin-producing E. coli, as this increases risk of hemolytic uremic syndrome and toxic megacolon 1, 5
• Avoid empiric antibiotics for mild, self-limited diarrhea in immunocompetent patients 4

Common Pitfalls to Avoid

• Do not assume all diarrhea is viral—bloody diarrhea or high fever mandates bacterial workup 1
• Do not delay rehydration while awaiting stool culture results 1, 4
• Do not use fluoroquinolones empirically due to 19% Campylobacter resistance rates 1, 4
• Do not treat asymptomatic carriers except for Salmonella Typhi in food handlers 4