Central  South  Dakota  Medical News
The Clinical View
by Phillip Hoffsten,M.D.
5 May 2004

WHAT IS FOOD POISONING?

     Several weeks ago, a gentleman came to the ER because he had had profuse diarrhea beginning in the early morning hours.  He related that he had been to another community at a very nice restaurant and had a meal there the night before.  He drove home to Pierre after the meal had been completed and felt no ill effects on his arrival at approximately midnight.  He went to bed and awakened with cramping abdominal pain about 2 hours later.  Shortly thereafter, he had a large loose stool and then another.  The cramping abdominal pain continued and in a short time, he had a third episode of diarrhea.  It was at this point, that he was beginning to feel faint and came into the hospital for evaluation.  He wasn’t sure what was wrong but was very suspicious that it was the food that he had eaten the night before.  A subsequent inquiry by the State Health Department eventually demonstrated that the problem was a salad bar in which the ingredients had been contaminated with a certain strain of bacteria called E coli strain 0517:H7.  This had been traced to bean sprouts that were in the salad bar.  The gentleman was briefly admitted to the hospital and administered intravenous fluids to deal with the dehydration from his diarrhea.  As in most cases of “food poisoning” the condition is self limited and only requires supportive care until the diarrhea stops spontaneously.  Contrary to what you might think, the use of medicine to stop the diarrhea may prolong the illness by keeping the toxic material in the bowel for a longer time.

     “Food poisoning” is one of the most common illnesses in the United States.  Annually, one out of three people will have an episode of food borne illness.  Surprisingly, only about 300,000 of the 76 million cases result in hospitalization and of these only 5,000 cases result in a mortality.  Be that as it may, the condition is very uncomfortable and definitely interferes with the person’s well being.

     The gentleman above inquired as to the nature of his illness and how it could be avoided.  Textbooks of medicine list over 25 different organisms that can contaminate food or water and cause food poisoning.  The gentleman was instructed that determining the cause of the food poisoning is usually a detective story in which the person has to trace backwards to the common source when multiple people got sick.  In isolated cases, it is very difficult to tell what the cause of the problem was.

     The most common causes of food poisoning include about 9 million cases a year of something called Norwalk agent.  This is a virus that comes from contaminated food especially when large batches of food are made by kitchen workers.  This is the most common problem that has been occurring on our cruise ships in which hundreds of people get infected at one time.  Avoidance of the problem depends upon how carefully food is prepared.

     Other common pathogens include the agent causing typhoid fever and a host of agents that cause dysentery like problems.  These agents are all spread from fecal contamination and again result from unclean preparation or incomplete cleaning of foods.

     One of the common causes of food poisoning is a small organism called giardia which frequently contaminates those beautiful mountain streams that we think are good enough to drink out of.  The reservoir for this agent is the raccoon and other wild animals whose urine contaminates those beautiful mountain streams.  No matter how good the water looks, it needs to be treated before it is consumed.

     Some episodes of food poisoning come from wonderful times and perfect intents.  The person who goes to a picnic with a large batch of potato salad made in the morning but not consumed until 6:00 pm while it is sitting in the sun runs a high likelihood of having staphylococcal food poisoning.  The staphylococcus infects the potato salad and sitting in the warm environment the staphylococcus multiplies very quickly.  The staphylococcus secretes a poison that causes food poisoning.  It is interesting that the organism itself is not so bad; it is the toxins that it secretes that cause the intestinal upset.

     As mentioned above, almost all cases of food poisoning are self limited.  A few such as giardia and campylobacter diarrhea in children are effectively treated with antibiotics.  In most cases, simple fluid replacement and avoidance of further contamination is all that is needed.

     Two special problems are worth mentioning.  One is called the MSG syndrome.  This is the so called Chinese restaurant syndrome where a person consumes a substantial amount of monosodium glutamate used to improve the flavor of Chinese food.  In rare individuals, this results in cramping, diarrhea, flushing, sweating, tingling, headaches and a profound sensation of doom that can last 2-3 hours.  Fortunately, the syndrome is self limited but very alarming when it occurs.  People that have ever had it seem to learn that they shouldn’t be eating at Chinese restaurants.

     A second problem that deserves special mention has to do with certain fish.  At certain times of the year, a so called red tide can occur that results from the natural growth of certain one celled animals in the ocean.  These one celled animals are consumed by the fish who are not bothered by the poison. However, if a fisherman catches the fish and then eats it, that can result in a condition called ciguatera.  This will begin as severe abdominal pain, nausea, vomiting, diarrhea that can last 24-48 hours.  Hospitalization is usually required for severe cases.  The message here is to be very careful about eating grouper, red snapper or amber jack fish from certain areas during certain times of the year.  Red snapper, I know is a delicious fish but one must be careful about the source of the fish and the time of the year.  In this case, the food poisoning is a true chemical problem and not really an infection.

     Thus in summary, food poisoning is a condition that results from contaminated food and comes in so many varieties that it is unusual we ever find the cause for sure.  Fortunately, treatment is usually supportive with replacing intravenous fluids and comfort measures for abdominal pain.  It is unusual that there is specific treatment or antibiotic that makes a difference except in the case of giardia and campylobacter.  Fortunately, there are diagnostic tests for those two organisms and we can make that diagnosis relatively quickly.

     The healthcare providers at your local clinics are well aware of these problems and how to help deal with them and alleviate the symptoms.