Food poisoning is when we get illness due to contaminated food. It is often food-borne gastroenteritis. Contamination of food usually occurs due to improper handling, preparation or storage of food or drinks.
For it to be considered a food poisoning outbreak, a cluster of 2 people with the same symptoms following ingestion of the same contaminated food or drink.
⚠️ Risk factors
- Consumption of undercooked meat, raw seafood canned foods unpasteurised soft cheeses raw eggs
- PPIs and antacids
- Recent history of travel
- Chronic disease
😷 Presentation
Similar to gastroenteritis.
- Diarrhoea - blood in the stool indicates mucosal invasion and requires more investigations.
- May be rice-watery stool and is suggestive of cholera.
- Nausea
- Vomiting
- Abdominal pain
- Fever
- Dehydration
🦠 Causative agents
- Campylobacter jejuni - most common of food poisoning in the UK. Common in chicken.
- It has a characteristic seagull shape.
- It releases an enterotoxin in the gut and invades the mucosa. Can cause bloody diarrhoea.
- Incubation period of 16-48 hours.
- Vomiting is rare
- Salmonella enteritidis/typhimurium - second most common cause of food poisoning in the UK. Incubation period of 16-48 hours.
- Bacillus cereus - incubation period of 30 minutes - 6 hours as there is a pre-formed toxin that is heat stable (so heating food keeps the toxin active). Rice is a common source.
- Staphylococcus aureus - incubation period of 1-6 hours. Most commonly in milk, puddings, pastries, sandwiches and sliced meat.
- Clostridium perfringens - incubation period is 12-24 hours. Red meat is a common source of infection.
- E. coli - E. coli O157 releases an enterotoxin that may cause bloody diarrhoea.
- Clostridium botulinum - associated with poorly preserved foods (such as honey). Leads to flaccid paralysis through the BoNT (botulinum neurotoxin).
- Scrombotoxin - another toxin that leads to an anaphylactic reaction. It is found in dark fish such as mackerel, tuna, salmon. Can be treated with anti-histamines.
- Shigella - releases Shiga-toxin and causes bloody diarrhoea.
🔍 Investigations
- Microscopy - assessing for WBCs and RBCs to differentiate invasive from non-invasive when suspecting pathogens such as E. coli O157.
- Culture - mandatory in patients with bloody stools.
- FBC and U&Es - may be useful to detect HUS when suspected.
🧰 Management
🥇 Oral rehydration and electrolyte replacement is the first-line treatment as it is usually self-limiting.
Empirical antibiotics (such as ciprofloxacin) are given in the very young, very old and immunocompromised. May also be given if there are systems of systemic toxicity (such as sepsis).
🚨 Complications
Generally seen in young children. It is generally secondary to infection (typical HUS) such as STEC, pneumococcal infection, HIV. Primary HUS may be due to dysregulation of complement.
😷 Presentations
It presents with a triad of:
- AKI
- Microangiopathic haemolytic anaemia - a normocytic anaemia.
- Thrombocytopenia
🔍 Investigations
- FBC
- Microangiopathic haemolytic anaemia - Hb <8g/dL and negative Coomb’s test
- Thrombocytopenia
- Schistocytes and helmet cells on blood film
- U&E - indicates AKI
- Stool culture - for identification of STEC infection.
🧰 Management
- Supportive treatment - fluids, blood transfusion and dialysis if required.
- Plasma exchange indications are complex, but generally it is reserved for severe cases of HUS that are not associated with diarrhoea. Eculizumab has evidence of grater efficiency than plasma exchange solely with an adult that has typical HUS.