Food poisoning refers to illness caused by consuming contaminated food or beverages. Contamination may result from bacteria, viruses, parasites, toxins, or chemical substances. Clinical presentation ranges from mild gastrointestinal distress to severe dehydration, neurological symptoms, and systemic toxicity. Proper diagnosis and management are essential to reduce complications and prevent outbreaks.
Types of Food Poisoning
1. Bacterial Food Poisoning
The most common type, caused by ingestion of bacteria or their toxins.
a. Staphylococcus aureus
- Preformed enterotoxin in food (milk, pastries, meat)
- Rapid onset: 1–6 hours
Symptoms: Severe vomiting, abdominal cramps.
Management: Oral rehydration; usually self-limiting.
b. Clostridium botulinum
- Found in improperly canned foods
- Produces botulinum neurotoxin
Symptoms: Diplopia, dysphagia, descending paralysis, respiratory failure.
Management: Botulinum antitoxin, mechanical ventilation.
c. Salmonella
- Contaminated eggs, poultry, water
Symptoms: Diarrhea, fever, abdominal pain.
Management: Rehydration; antibiotics only for severe cases.
d. Bacillus cereus
Two types:
- Emetic type: rice dishes → vomiting
- Diarrheal type: meat/vegetables → diarrhea
e. Vibrio cholerae
- Contaminated water and seafood
Symptoms: Profuse “rice-water” stools, severe dehydration.
Management: Aggressive oral/IV rehydration; antibiotics shorten illness.
2. Viral Food Poisoning
- Norovirus: leading cause of outbreaks
- Rotavirus: common in children
Symptoms: Vomiting, watery diarrhea, low-grade fever.
Management: Rehydration; no specific antiviral therapy.
3. Parasitic Food Poisoning
- Giardia lamblia
- Entamoeba histolytica
- Toxoplasma gondii
Symptoms: Chronic diarrhea, malabsorption (Giardia), bloody diarrhea (E. histolytica).
Management: Metronidazole or appropriate antiparasitic drugs.
4. Chemical Food Poisoning
- Pesticides
- Heavy metals
- Food additives
Symptoms vary depending on the chemical involved.
Common Toxins in Food Poisoning
1. Aflatoxins
- Produced by Aspergillus on grains and nuts
- Causes hepatotoxicity and liver cancer
2. Scombrotoxin (Histamine Poisoning)
- Spoiled fish (tuna, mackerel)
- Flushing, headache, vomiting
3. Ciguatera Toxin
- Reef fish (barracuda, snapper)
- Neurological symptoms: hot–cold reversal
4. Mushroom Toxins
- Amanita species → severe hepatotoxicity
Clinical Features of Food Poisoning
- Nausea and vomiting
- Diarrhea (watery or bloody)
- Abdominal cramps
- Fever (bacterial causes)
- Neurological signs (botulism, ciguatera)
- Dehydration and electrolyte loss
Diagnosis
- History of food exposure
- Stool microscopy and culture
- Electrolytes and renal function
- Toxin assays (botulism, cholera) when available
Management
1. Rehydration (Mainstay of Treatment)
- Oral rehydration solution for mild–moderate dehydration
- IV fluids for severe dehydration
2. Symptomatic Care
- Antiemetics
- Antipyretics
- Probiotics to restore gut flora
3. Antibiotic Therapy (Only When Indicated)
- Severe Salmonella or Shigella infections
- Cholera
- Traveler’s diarrhea caused by E. coli
Unnecessary antibiotics may worsen symptoms or cause resistance.
4. Specific Treatments
- Botulism: botulinum antitoxin
- Amoebiasis: metronidazole
- Giardiasis: tinidazole or metronidazole
Prevention
- Wash hands before handling food
- Avoid raw or undercooked meat, eggs, and seafood
- Store food at safe temperatures
- Drink clean, treated water
- Maintain kitchen hygiene
Detailed Notes:
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PATH: PHARMD/ PHARMD NOTES/ PHARMD FOURTH YEAR NOTES/ CLINICAL TOXICOLOGY/ FOOD POISONINGS.