Does Your Patient Have a Foodborne Disease?

David W.K. Acheson, MD, FRCP


April 01, 2002

In This Article

Clinical Manifestations

To make a diagnosis of foodborne disease, one must first consider the spectrum of clinical manifestations.[2] Foodborne disease typically manifests as a mixture of nausea, vomiting, fever, abdominal pain, and diarrhea. However, it is important to remember that some foodborne diseases may manifest in a way that is not focused on the gastrointestinal tract. For example, paralysis could be due to botulism or some types of shell fish poisoning, headaches and paresthesia could be caused by ciguatera fish poisoning or scromboid, amnesia may result from shell fish poisoning, hepatitis could be the result of hepatitis A or E, and meningitis or spontaneous abortion may be caused by Listeria monocytogenes.

The physician should consider 3 important factors while trying to determine the differential diagnosis of foodborne diseases: the presenting symptoms, exposure to a particular type of food associated with foodborne disease, and the interval between exposure to the suspect food and the onset of symptoms. Examples of the types of questions to ask in relation to obtaining a food history are shown in Table 2. Having made this determination, the physician may then be able to decide what tests to order -- if any -- that will confirm the diagnosis.

An understanding of the basic pathogenetic mechanisms can also help in understanding the differential diagnosis of foodborne disease. Microbes generally cause foodborne disease through 3 pathogenic mechanisms: preformed toxins, toxins that are formed after ingestion, and directly pathogenic organisms.

Consumption of foods with preformed toxins usually leads to rapid (6-12 hours) onset of predominantly upper gastrointestinal symptoms. Examples of organisms that produce such toxins are Staphylococcus aureus, Bacillus cereus, and botulism. Symptoms from microbes that make toxinsafter ingestion usually take longer to manifest (approximately 24 hours or longer). These toxins cause diarrhea that may be watery (eg, enterotoxigenic Escherichia coli) or bloody (eg, Shiga toxin-producing E coli [STEC]). Directly pathogenic organisms damage the epithelial cell surface and can actually cross the intestinal epithelial cell barrier. These organisms have a wide clinical spectrum, ranging from watery diarrhea (eg, C parvum, enteric viruses) to inflammatory diarrhea (eg, Salmonella, Campylobacter, or Shigella species) or systemic disease (eg, L monocytogenes).

To simplify the diagnostic approach, various major presenting symptoms will be discussed in the context of the most likely microbial causes. This is summarized in Table 3. Although management of foodborne disease is beyond the scope of this article, treatment of many types of foodborne illness has been reviewed recently by a panel of experts in the context of treating diarrheal disease.[3]