Food poisoning occurs when you swallow food or water that contains bacteria, parasites, viruses, or toxins made by these germs. Most cases of food poisoning are from common bacteria such as Staphylococcus or E. coli.
The germs may get into the food you eat (called contamination) in different ways:
- Meat or poultry can come into contact with the normal bacteria from the intestines of an animal that is being processed
- Water that is used during growing or shipping can contain manure or human waste
- Food handling or preparation in grocery stores, restaurants, or homes
Food poisoning often occurs from eating or drinking:
- Any food prepared by someone who does not use proper hand washing techniques
- Any food prepared using cooking utensils, cutting boards, and other tools that are not fully cleaned
- Dairy products and other foods that have sat out of the refrigerator too long
- Frozen or refrigerated foods that are not stored at the proper temperature or are not reheated properly
- Raw fish or oysters
- Raw fruits or vegetables that have not been washed well
- Raw vegetable or fruit juices and dairy (look for the word "pasteurized")
- Undercooked meats or eggs ;
- Water from a well or stream, or city or town water that has not been treated
- Food poisoning can be caused by:
- Botulism (Clostridium botulinum)
- Campylobacter enteritis
- E. coli enteritis
- Fish poisoning
- Many different viruses
- Staphylococcus aureus
Who are at risk?
- Infants and elderly people are at the greatest risk for food poisoning. You are also at higher risk if:
- You have a serious medical condition, such as kidney disease or diabetes
- You have a weakened immune system
- You travel outside to areas where there is more exposure to organisms that cause food poisoning
The symptoms from the most common types of food poisoning generally start within 2 - 6 hours of eating the food. That time may be longer (even a number of days) or shorter, depending on the cause of the food poisoning.
Possible symptoms include:
- Abdominal cramps
- Diarrhea (may be bloody)
- Fever and chills
- Nausea and vomiting
- Weakness (may be serious and lead to respiratory arrest, as in the case of botulism)
Your doctor will examine you for signs of food poisoning, such as tenderness in the abdomen and dehydration. Your doctor will also ask about foods you have eaten recently.
Tests to find the cause may be done on your:
Even if you have food poisoning, however, these tests may not be able to prove it.
- Leftover food
In rare but possibly serious cases, your doctor may order one or more of the following procedures:
- A thin, tube-like tool placed in the anus to look for the source of bleeding or infection (sigmoidoscopy)
- A test to measure electric impulses in the muscles (electromyography) to check for botulism
- A test of fluid from the spine (lumbar puncture) if you have signs of a nervous system disorder
You will usually recover from the most common types of food poisoning within a couple of days. The goal is to make you feel better and avoid dehydration.
If you have diarrhea and are unable to drink fluids (for example, due to nausea or vomiting), you may need medical attention and fluids given through a vein (by IV). This is especially true for young children.
- Don't eat solid foods until the diarrhea has passed, and avoid dairy products, which can worsen diarrhea (due to a temporary state of lactose intolerance).
- Drink any fluid (except milk or caffeinated beverages) to replace fluids lost by diarrhea and vomiting.
- Give children an electrolyte solution sold in drugstores.
If you take diuretics, you need to manage diarrhea carefully. Talk to your doctor-- you may need to stop taking the diuretic while you have the diarrhea. Never stop or change medications without talking to your doctor and getting specific instructions.
For the most common causes of food poisoning, your doctor would NOT prescribe antibiotics.
You can buy medicines at the drugstore that help slow diarrhea. Do not use these medicines without talking to your doctor if you have bloody diarrhea or a fever. Do not give these medicines to children.
If you have eaten toxins from mushrooms or shellfish, you will need medical attention right away. The emergency room doctor will take steps to empty out your stomach and remove the toxin.
Most people fully recover from the most common types of food poisoning within 12 - 48 hours. Serious complications can arise, however, from certain types of food poisoning
Dehydration is the most common complication. This can occur from any of the causes of food poisoning.
Less common but much more serious complications include:
- Arthritis (Yersinia and Salmonella)
- Bleeding disorders (E. coli and others)
- Death (from mushrooms, certain fish poisonings, or botulism)
- Kidney problems (Shigella, E. coli)
- Nervous system disorders (Botulism, Campylobacter)
- Pericarditis (Salmonella)
- Respiratory distress, including the need for support on a breathing machine (botulism)
To prevent food poisoning, take the following steps when preparing food:
- Carefully wash your hands often, and always before cooking or cleaning. Always wash them again after touching raw meat.
- Clean dishes and utensils that have had any contact with raw meat, poultry, fish, or eggs.
- Use a thermometer when cooking. Cook beef to at least 160°F, poultry to at least 180°F, and fish to at least 140°F.
- DO NOT place cooked meat or fish back onto the same plate or container that held the raw meat, unless the container has been completely washed.
- Promptly refrigerate any food you will not be eating. Keep the refrigerator set to around 40°F and your freezer at or below 0°F. DO NOT eat meat, poultry, or fish that has been refrigerated uncooked for longer than 1 to 2 days.
- Cook frozen foods for the full time recommended on the package.
- DO NOT use outdated foods, packaged food with a broken seal, or cans that are bulging or have a dent.
- DO NOT use foods that have an unusual odor or a spoiled taste.
- DO NOT drink water from streams or wells that are not treated. Only drink water that has been treated or chlorinated.
- If you take care of young children, wash your hands often and dispose of diapers carefully so that bacteria can't spread to other surfaces or people.
- If you make canned food at home, be sure to follow proper canning techniques to prevent botulism.
- DO NOT feed honey to children under 1 year of age.
- DO NOT eat wild mushrooms.
- When traveling where contamination is more likely, eat only hot, freshly cooked food. Drink water only if it has been boiled. DO NOT eat raw vegetables or unpeeled fruit.
- DO NOT eat shellfish that has been exposed to red tides.
- If you are pregnant or have a weakened immune system, DO NOT eat soft cheeses.
Call your doctor if:
- Diarrhea lasts for more than 2 - 3 days
- There is blood in your stools
- You have diarrhea and are unable to drink fluids due to nausea or vomiting
- You have a fever over 101°F
- You have signs of dehydration (thirst, dizziness, light-headedness)
- Bleeding is excessive or your stools are maroon or black
- You may have poisoning from mushrooms, fish, or botulism
- Your heart is racing, pounding, or skipping
This is the name for a condition in which the membrane that covers the heart (known as the pericardium) becomes inflamed, often as a result of a bacterial or viral infection.
The pericardiumThis fluid filled sac surrounds the heart and performs a range of vital functions which include:
- Securing the heart in its current position
- Acting as a form of protection (shock absorption)
- Preventing the heart from over-increasing in size as blood volume increases.
If the pericardium becomes inflamed it results in severe chest pain but there is likely to be minimum damage to the heart itself.
How does this relate to food poisoning?
Pericarditis can be caused by a bacterial, viral or parasitical infection, for example the salmonella bacteria.
The salmonella bacteria are responsible for an unpleasant form of food poisoning; however, there are other types of bacteria which also cause food poisoning and pericarditis.
- E coli
- Clostridium perfringens
- Staphylococcus aureus
These cause ‘bacterial pericarditis’.
Causes of pericarditis
There are a variety of causes, most of these being viral infections such as ‘the flu’virus or the herpes simplex virus.
Bacterial infections are another reason which includes the strains of bacteria described above which are responsible for food poisoning.
Other causes include:
- Serious injury or accident which involves the chest
- Autoimmune disease, e.g. rheumatoid arthritis
- Radiotherapy: as part of cancer treatment
- Heart attack
- Heart surgery
In many cases of pericarditis there is no obvious cause. This is known as ‘idiopathic pericarditis’.
Symptoms of pericarditis
The main symptom is chest pain which is usually localised in the centre of the chest and worsens if you take a deep breath or cough. Lying flat also worsens this although sitting upright will ease it.
This pain may spread to your arms, left shoulder or neck.
It is easy to mistake this pain as a sign of a heart attack and, indeed, this is something which many people do. Any sudden chest pain needs to be investigated, irrespective of whether it is pericarditis or another type of heart complaint.
In this situation seek urgent medical advice.
Other symptoms include:
- Swollen abdomen and/or legs
Complications of pericarditis
Complications are rare but do happen so it is as well to be aware of these. They include irregular heart beats (arrhythmia), cardiac tamponade and constrictive pericarditis. Chronic heart failure is another risk.
ArrhythmiaThis is an abnormal heart rate or rhythm which can either be too fast or too slow; or where the heart is unable to pump blood which causes it to collapse. These are life threatening conditions which need emergency medical treatment.
Cardiac tamponadeCardiac tamponade is where there is an excess amount of fluid inside the pericardium which puts pressure on the heart. This prevents it from pumping blood around the body as per normal.
This is a life threatening condition and requires emergency treatment.
Constrictive pericarditisThe tissue of the pericardium becomes scarred and thickens which then compresses (constricts) the heart. This prevents the heart from fully expanding as it beats and affects blood flow around the body.
This results in symptoms of heart disease.
Surgery is required to remove the scarring and to release this compression of the heart.
Chronic heart failureThis is an umbrella term used to describe a range of conditions which affect the ability of the heart to pump blood around the body.
Diagnosing pericarditisYour doctor will examine you, ask you about your symptoms and your medical history. He or she will ask you if you have experienced any recent bacterial or viral infections so mention to him/her if you had food poisoning.
Do this if you have had salmonella poisoning or any of the other three bacterial infections mentioned here.
You will be referred for tests which include:
- Blood tests
- ECG (electrocardiogram)
- CT/MRI scans
Treatment for pericarditisThis will depend upon the cause and whether your condition is such that you can be treated at home or require admission to hospital.
If you developed complications then hospital admittance is more than likely and means that your condition can be carefully monitored.
This will depend upon the results of your tests. If, for example, you have undergone an echocardiogram and this shows an excess of fluid around the pericardium plus a weak immune system then hospitalisation will be necessary.
EchocardiogramAn echocardiogram is the name for an ultrasound scan of the heart. This produces accurate images of the heart; its chambers, valves and well (or not) it is working.
The procedure is very similar to that performed during a pregnancy. It consists of a handheld device called a probe which is connected to an ultrasound monitor. This probe is placed onto your chest and moved around.
Ultrasound pulses are transmitted by the probe, through the skin and towards the heart. These then ‘echo’ (or reverberate) back from the heart to an ECG machine via the probe. These echoes appear as a series of images of the heart on the ultrasound monitor.
MedicationIf your pericarditis has been caused by food poisoning then you will treated for that as well as the pericarditis. If your food poisoning has a bacterial source then antibiotics can be prescribed. But antibiotics are ineffective against viral food poisoning and other viral infections.
You will be given additional medication which is designed to treat pericarditis which includes non-steroidal anti-inflammatory drugs (NSAIDs), steroids or colchicine.
NSAIDs are effective at easing any chest pain and inflammation in the pericardium. An example of these is ibuprofen.
Steroids are given to block the effects of the immune system, preventing any further release of antibodies and so help to reduce the inflammation. However, they are only prescribed if there is a dangerous build up of fluid within the pericardium or if an NSAID/colchicine is ineffective.
Colchicine is a treatment for gout which is also effective against pericarditis. It works by destroying many of the cells of the immune system that cause this inflammation which then reduces any inflammation within the pericardium.
This is given in recurring cases of pericarditis or if someone is unable to take NSAIDs.
If you have suffered a bout of bacterial food poisoning and suspect that you may have developed pericarditis then contact your doctor.