Common organisms causing food contamination include bacteria, viruses, parasites or their toxins. Food poisoning
commonly presents with fever, nausea, vomiting, abdominal cramping pain and diarrhea
Campylobacter, salmonella, staphylococcus aureus, listeria, botulinum, E.coli are some of the common organisms causing food poisoning.
Some people are more prone to food poisoning than others due to certain factors. Some of those risk factors are older individuals, young children and infants, pregnancy and immunocompromised persons (ones with a weak immune system due to long standing chronic conditions like diabetes, HIV, liver disease or those who are on treatment for cancers).
History, presentation, examination and investigations are useful in arriving on diagnosis. Investigations like stool examination with culture, blood work up, imaging modalities (only when needed) are helpful in concluding on diagnosis.Symptoms of food poisoning can mimic various conditions like:
- Appendicitis – It is the inflammation of the appendix located at the caecum. It happens due to blockage of the opening of the appendix. Colicky pain that is of sudden onset `around the navel progressing to the right iliac region, fever, chills, nausea, diarrhea/constipation and loss of appetite are some of the common symptoms of appendicitis. Physical examination, abdominal ultrasound and blood investigations are useful in concluding on the diagnosis.
- Acquired or congenital enzyme deficiency – The most common enzyme deficiency is lactose intolerance. It presents with bloating diarrhea, vomiting, nausea, abdominal pain and flatulence after consuming dairy products. Symptoms may arise from 30 minutes to 2 hours after consumption of lactose containing dairy products. History, presentation and investigations like lactose tolerance test, hydrogen breath test and stool acidity test are useful in making the diagnosis.
- Addison disease – It is due to damage to the adrenal glands, producing very low quantity of hormones (cortisol and also aldosterone). Common symptoms are nausea, vomiting, diarrhea, weight loss, muscle weakness, joint pains, fatigue, skin darkening, sexual dysfunction, loss of body hair, low blood pressure and low blood sugar levels. Estimation of sodium, potassium, cortisol and adrenocorticotropic hormone levels are helpful in identifying the cause. CT scan abdomen and MRI brain are ordered based on the results of blood investigations.
- Heavy metal poisoning – It is due to accumulation of heavy metals in the soft tissues of the body in toxic amounts leading to various problems. Lead, mercury, arsenic and cadmium are the common metals causing toxic effects. Presentation varies depending upon the metal causing the symptoms. Blood investigations, urine estimation of metals, chest X –ray and X-ray of long bones are useful in making the diagnosis.
- Malabsorption syndromes – It is a condition in which the intestines are unable to process the food we eat and hence absorption of nutrients from the food becomes difficult. Malabsorption occurs due to underlying conditions like celiac disease, lactose intolerance, genetic conditions, Whipple’s disease, short bowel syndrome etc. Weight loss, bloating, abnormal stools or chronic diarrhea are common. Eliciting a proper history, physical examination and certain investigations like stool examination, X-ray abdomen, and endoscopy are useful in concluding on the diagnosis.
- Inflammatory bowel disease – It is a chronic inflammation of the intestine (whole or segmental). Ulcerative colitis and Crohn’s disease are two entities that come under inflammatory bowel disease. Abdominal cramping with pain, mucus and/or blood in stools, loss of appetite, unintentional weight loss, nausea, bloating, diarrhea/ constipation are the common symptoms with this condition. Sigmoidoscopy, colonoscopy, Upper endoscopy, X-ray abdomen, CT abdomen, barium studies are useful in arriving on diagnosis.
Frequently Asked Questions1. What is Food poisoning?
Food poisoning, as the name suggests is the transmission of infection from bacteria, viruses or their toxins due to ingestion of contaminated food.2. What are the common pathogens causing food poisoning?
Common pathogens causing food poisoning include campylobacter, clostridium, E.coli, salmonella and staphylococcus. 3. What are the common symptoms of food poisoning?
Symptoms of food poisoning include abdominal cramps, diarrhea, nausea, vomiting, headache, fever and fatigue. 4. How is food poisoning diagnosed?
Food poisoning may be diagnosed with the help of a detailed history, examination (e.g. looking for signs of dehydration), stool examination with culture and if required sigmoidoscopy can also be ordered.