Food poisoning
Food poisoning is an illness caused by consuming foods and drinks contaminated with microbes such as bacteria (or bacterial toxins), viruses, and parasites, or sometimes heavy metal toxins, leading to gastrointestinal problems with differing severity due to multiple factors. The most common symptoms include abdominal pain, nausea, vomiting, diarrhea, and fever.
Causes, risk factors, and conditions contributing to food poisoning
As mentioned earlier, food poisoning is caused by food or drink contamination with infectious organisms. Germs can pass from infected people preparing food without washing their hands before cooking or from contaminated foods or drinks that are not correctly washed or adequately heated. Germs on one food can be passed on to another by sharing the same utensils, such as a cutting board or knife. Leaving foods at a temperature suitable for the growth of germs can also lead to food poisoning.
Factors influencing infection or symptom severity variation among people are, for example:
- Age and medical conditions: Certain pathogens such as rotavirus usually cause illness in children than in adults; it is probably due to alteration of the intestinal mucus layer in the small intestine. Certain medical conditions that weaken the immune system lead to individual symptom severity variations.
- Personal hygiene: Good personal hygiene can limit the number of germs below the threshold that can invade our body.
- Gastric acid and bowel movement: Stomach acid can kill germs in foods we consume. Healthy bowel peristalsis can distribute normal flora to help kill the invading pathogen.
Symptoms and complications of food poisoning
Symptoms can begin within a few hours or days after exposure to contaminated foods. Common symptoms are gastrointestinal upsets such as nausea, vomiting, diarrhea (either watery or mucous-bloody), abdominal cramps, and fever. There are some specific symptoms indicating the specific pathogen, such as predominant vomiting symptoms that may be caused by Staphylococcus aureus, B cereus, or Norovirus, while large-volume rice-water diarrhea is caused by Vibrio cholerae.
Other symptoms that reflect the body’s hydration status such as dry mouth and throat, dark urine, dizziness when sitting up or changing position, blurred vision, and passing out in severe cases should be evaluated and promptly treated if present.
When to see a doctor
Please seek medical care if you experience severe food poisoning symptoms as follows:
- Diarrhea, more than 6 times per day
- Diarrhea or vomiting which contains blood
- Fever with a temperature over 38.5 oC (101.3 oF) after the first day
- Severe abdominal cramps
- Unable to eat anything
- High-risk underlying conditions, for example if you are over 70 years old or have medical conditions such as heart diseases or strokes, diseases with weakened immunity such as diabetes and chronic kidney diseases, or you are taking immunosuppressants.
- Signs of dehydration such as fatigue, dizziness and blacking out when sitting up, confusion, unconsciousness, dark urine, or no urination longer than 6 hours.
Prevention
Personal hygiene plays a vital role in preventing food poisoning. It is essential to wash your hands before eating or after activities that could cause contamination, such as going to a toilet, blowing your nose, touching pets or animals, disposing of garbage, or changing diapers. With ongoing food poisoning symptoms, you can pass on the disease to others; therefore, you should avoid contacting others while still sick.
Another important preventive measure is being mindful of food safety. You should avoid taking unpasteurized milk. Wash fruits and vegetables thoroughly before eating or cooking, and maintain the refrigerator temperature below 4.4 oC (40 oF) and the freezer below -18 oC (0 oF). Eat only well-cooked foods with adequate heating and clean kitchen utensils after using them on raw ingredients.
Diagnosis and additional tests
Your doctor can diagnose based on your symptoms and physical examination to assess your hydration status. Additional tests are usually unnecessary except in patients with severe symptoms who may require a blood test to check the kidney function and electrolyte imbalance. A blood culture may be ordered in patients with high fever or suspected severe infection.
A stool test detects inflammatory white blood cells indicative of colonic infection by invasive bacteria. The doctor may consider stool pathogen identification for patients with inflammatory diarrhea, weakened immunity, persistent symptoms longer than 2 weeks, or patients who may be linked to an outbreak.
Other tests such as endoscopy are not essential for diagnosing acute food poisoning. However, if diarrhea lasts longer than 2 weeks without a clear cause, the doctor may consider upper and lower GI endoscopy to delineate the cause.
Treatment
In most cases, food poisoning resolves on its own without specific treatments. Treatments aim to maintain the balance of fluids and electrolytes lost through diarrhea and vomiting. Replacing lost fluids and electrolytes with oral electrolyte solutions will gradually improve and resolve the symptoms within 3-5 days. However, if patients have the danger signs mentioned earlier, please seek immediate medical attention; intravenous (IV) fluids may be administered to replace the lost fluids and electrolytes, which cannot be rehydrated in time with an oral electrolyte solution.
Antibiotics benefit patients with signs and symptoms of invasive infection such as high fever, mucous-bloody diarrhea, and fecal white blood cells.
Moreover, ancillary medications such as antidiarrheal, antispasmodics, or anti-emetic agents can be taken to relieve the symptoms. However, antidiarrheal agents should be used cautiously, particularly in patients with inflammatory diarrhea or children.
