Food Poisoning — Recognition and Field Treatment

Food poisoning presents with gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal cramping) that appear within hours of consuming contaminated food. Use symptom onset timing as the primary clue to identify the likely pathogen:

• 1-6 hours onset: Bacterial toxins (Staphylococcus aureus, Clostridium perfringens) or preformed toxins. Symptoms typically resolve within 24 hours.
• 6-24 hours onset: Salmonella species. Often includes fever (>101°F/38.3°C) and may have bloody diarrhea.
• 24-72 hours onset: Viral pathogens (norovirus) or bacterial toxin-producing organisms (E. coli O157:H7, Campylobacter). Norovirus typically features rapid onset of severe vomiting; E. coli often presents with bloody diarrhea.

Note the time of exposure and symptom onset. Ask about food source, who else ate the same food, and current symptoms. This timing assessment guides treatment decisions.

Upon recognizing food poisoning, take these immediate steps:

1. Assess the person's current condition: Check vitals (heart rate, respiratory rate, temperature). Assess mental status and ability to drink.
2. Do NOT induce vomiting in most cases. Only consider vomiting induction if: ingestion occurred within the last 30 minutes, AND the substance is not caustic (no acids, bases, hydrocarbons), and the person is conscious and can protect their airway. In wilderness settings, if needed, have the person drink warm salt water (1 teaspoon salt per cup) or place a finger in the throat. Do not use ipecac.
3. Monitor for signs of dehydration: Dry mucous membranes, dark urine, decreased urination, dizziness, weakness, rapid heart rate.
4. Position the person: If vomiting is occurring, place them in a side-lying position to prevent aspiration. Have them rest in a cool, comfortable location away from food preparation.

If the person cannot keep fluids down, shows signs of severe dehydration, has high fever (>104°F/40°C), or is altered mentally, plan for evacuation to medical care.

Dehydration is the primary danger in food poisoning. Use an oral rehydration solution (ORS) rather than plain water or sugary drinks, as ORS contains the correct balance of electrolytes and glucose for intestinal absorption.

Creating ORS in the field:

• Mix 1 liter of clean water with 6 teaspoons of sugar and 1/2 teaspoon of salt
• Alternatively: 1 liter water + 8 teaspoons sugar + 1 teaspoon salt (slightly less concentrated version)
• Stir until completely dissolved

Administration technique:

• Offer small, frequent sips (5-10 mL or 1-2 teaspoons every 5-10 minutes)
• Do NOT give large gulps or rapidly consume large volumes—this triggers more vomiting
• If person is actively vomiting, wait 10-15 minutes between sips
• Continue small sips even if vomiting occurs; some fluid will be absorbed
• Avoid carbonated beverages, caffeine, and high-sugar drinks

Goal: Replace losses gradually over hours. A person losing 1-2 liters of fluid should receive similar replacement over 3-4 hours.

If the person cannot keep any fluids down for more than 4 hours, or shows signs of severe dehydration (extreme thirst, profound weakness, confusion), this requires medical evaluation.

Examine the diarrhea to assess severity and determine appropriate treatment:

Assess the following:

1. Frequency: How many stools per hour? (Mild: 1-2/hour; Moderate: 3-5/hour; Severe: >5/hour)
2. Presence of blood: Any visible red blood in stool?
3. Presence of mucus: Slimy appearance or clear mucus in stool?
4. Fever: Take temperature. Fever >100.4°F (38°C) suggests bacterial or parasitic infection.
5. Abdominal pain: Mild cramping (common) vs. severe pain (concerning).
6. Duration: How long has diarrhea been occurring?

Interpretation:

• No fever, no blood, mild cramping: Likely viral or toxin-mediated. Hydration is primary treatment.
• Fever present, especially with bloody diarrhea: Likely bacterial infection. May benefit from antibiotics if severe.
• Severe, frequent diarrhea with rapid dehydration: Assess evacuation need.
• Abdominal pain out of proportion: Consider other causes and plan evacuation.

Record these observations—they guide medication use and evacuation decisions.

Blood in diarrhea combined with high fever suggests invasive bacterial infection. Evacuation may be necessary.

Loperamide (Imodium) can provide symptomatic relief but must be used carefully in food poisoning:

When to USE loperamide:

• No fever (temperature <100.4°F / 38°C)
• No blood in stool
• No mucus in stool
• Diarrhea is primarily a nuisance (not debilitating)
• No severe cramping
• Person is able to stay hydrated

Dosing:

• Initial dose: 4 mg (2 capsules of 2 mg each) after first loose stool
• Subsequent doses: 2 mg (1 capsule) after each loose stool
• Maximum: 16 mg per day; use for 2-3 days maximum

When to AVOID loperamide:

• Fever is present (suggests bacterial infection that needs to exit the body)
• Blood or significant mucus in stool (sign of invasive infection)
• High-volume diarrhea with rapid dehydration
• Severe abdominal pain
• Person appears systemically ill

Rationale: Loperamide slows intestinal motility. However, in bacterial dysentery, slowing transit allows the pathogen to invade deeper into the intestinal wall, potentially worsening infection.

Never use loperamide in the presence of fever or bloody diarrhea. If unsure, do NOT use it.

Some food sources pose threats beyond typical food poisoning. Recognize these dangers:

Botulism (Clostridium botulinum toxin):

• Source: Often home-canned foods (vegetables, meats) with inadequate heating; also vacuum-sealed foods at room temperature
• Onset: 12-72 hours (occasionally up to 10 days)
• Warning signs: Descending paralysis (starts with head, moves downward)—blurred vision, double vision, difficulty swallowing, weak voice, drooping eyelids, then arm and leg weakness, respiratory failure
• Key feature: Normal temperature (no fever) and normal mental status despite severe symptoms
• Treatment in field: Immediate evacuation. There is no field treatment. Antitoxin exists only in hospitals.
• Action: Do NOT wait for paralysis to worsen; evacuate at first signs of vision changes or difficulty swallowing

Mushroom Poisoning (hepatotoxic varieties like Amanita phalloides):

• Source: Foraged mushrooms, especially if picked by inexperienced foragers
• Onset of severe symptoms: 24-48 hours after ingestion (deceptive symptom-free period)
• Initial symptoms (first 6-24 hours): Nausea, vomiting, abdominal pain (often mild)
• Severe phase (24-48+ hours): Liver failure begins—jaundice, dark urine, coagulopathy (bleeding)
• Field treatment: If <1 hour since ingestion, activated charcoal 50 g may reduce toxin absorption. After 1 hour, charcoal is ineffective.
• Management: Supportive care, hydration, immediate evacuation for hospital-based management (possible liver transplant may be needed)

Botulism and mushroom poisoning both require hospital care. Evacuate immediately if suspected—these conditions can be fatal without proper medical intervention.

When multiple people become ill after eating together, identifying the shared contaminated food is crucial for preventing further exposure:

Investigation steps:

1. Interview all affected individuals: What did each person eat? What did unaffected people eat? Sometimes only those who ate a specific item become ill.
2. Identify the common food: The contaminated food is eaten by all sick people but not (or rarely) by well people.
3. Consider the food's characteristics: High-risk foods include undercooked poultry, unpasteurized dairy, deli meats, seafood, home-canned foods, and foods left at room temperature >2 hours.
4. Discard the suspected food: If still present, do not taste-test. Discard safely to prevent further exposure.
5. Clean food preparation surfaces: Wash all surfaces and utensils that contacted the suspected food with soap and water.
6. Coordinate symptom timing: If all became ill at similar times, this confirms a shared source and narrows the probable pathogen based on incubation period.
7. Report if in civilization: In developed areas, report to local health department—public health investigations confirm pathogens and prevent community-wide illness.

Relevance to treatment: If the group becomes ill with fever and bloody diarrhea (suggesting Salmonella or E. coli), antibiotics may be considered for severely ill patients.

Do not allow people to continue eating food from the suspected source. Ensure contaminated food is discarded securely.

Antibiotics are indicated only in specific scenarios with confirmed or highly probable bacterial infection:

Indications for antibiotics:

1. Salmonella infection (fever + diarrhea with 6-24 hour onset, often with blood or mucus):

   • Severe infection: Ciprofloxacin 500 mg orally twice daily for 5-7 days
   • Alternative: Azithromycin 500 mg day 1, then 250 mg daily for 4 more days
   • Mild-moderate infection: Often self-limited

2. Campylobacter infection (fever, bloody diarrhea, severe cramping, 2-5 day onset):

   • Ciprofloxacin 500 mg orally twice daily for 5-7 days
   • Alternative: Azithromycin as above

3. Giardia or other parasites (chronic diarrhea or known contaminated water exposure):

   • Metronidazole 250 mg orally three times daily for 5-7 days, OR
   • Tinidazole 2 g single dose

4. E. coli O157:H7 (bloody diarrhea, no fever or low fever):

   • Do NOT use antibiotics—they increase risk of hemolytic uremic syndrome (HUS)
   • Supportive care and evacuation if severe

Important notes: Antibiotics are not available in true wilderness; plan evacuation if bacterial infection is suspected. Most mild food poisoning resolves without antibiotics.

Using antibiotics in E. coli O157:H7 infection can trigger kidney failure (hemolytic uremic syndrome). Do NOT use antibiotics unless bacterial species is confirmed and it is not O157:H7.

As the person recovers from food poisoning, gradually restore nutrition and monitor for relapse:

Timeline for recovery:

• Acute phase (first 24-48 hours): Hydration only (ORS, water, broth)
• Early recovery (24-48 hours onward): Begin bland foods as tolerated
• Full recovery: 3-5 days for most viral/toxin-mediated cases; 5-7 days for bacterial

BRAT diet (for initial food reintroduction):

• Bananas: Provide potassium, pectin (aids stool binding), easy to digest
• Rice: White rice or rice-based foods; bland carbohydrate
• Applesauce: Provides pectin, calories, tolerable sweetness
• Toast: Plain white bread toast; source of carbohydrates

Additional foods to introduce gradually:

• Crackers (saltine crackers)
• Broths (vegetable or chicken, low fat)
• Plain cooked vegetables (carrots, potatoes, green beans)
• Plain cooked chicken or lean meats (after 2-3 days)
• Eggs (if person is recovering well)

Foods to AVOID during recovery:

• Dairy products for 24-48 hours post-diarrhea—lactose intolerance is common during recovery
• Fatty foods (fried foods, fatty meats, oils)
• Spicy foods
• High-fiber foods (until stool has normalized)
• Caffeine and alcohol
• Sugar-heavy items

Return to normal diet: Gradually return to normal foods over 3-5 days. Reintroduce dairy last. If diarrhea recurs, avoid that food for another 24 hours.

Monitoring: Watch for recurrence of symptoms, dehydration signs, and report if diarrhea continues beyond 7 days.

Reintroducing too much food too quickly can restart diarrhea. Go slow—a bland diet for 2-3 days saves suffering later.