Sooner or later, every primary care physician will get a call from a patient who says something like, “Doc, I think I ate something bad. I've been sick for 3 days and I'm not getting better.”
It's no surprise, given that the CDC currently estimates 1 in 6 Americans will be sickened by a foodborne pathogen each year, and of those, 128,000 will be hospitalized and 3,000 will die.
Internal medicine staff such as nurse practitioners or physician assistants can start the screening process on the telephone and help determine which patients should be sent right to the ED, said Joel Kammeyer, MD, MPH, FACP, an infectious disease specialist at ProMedica Toledo Hospital in Ohio. “The most important things they should watch for are severe dehydration, sudden and severe abdominal pain, bloody diarrhea with fever, and blurred or double vision or muscle weakness.”
If an office visit is deemed appropriate, staff can also order tests, said Stuart H. Cohen, MD, FACP, chief of the division of infectious diseases, director of hospital epidemiology and infection control, and professor in the department of internal medicine at the University of California, Davis.
“You could make this semi-algorithmic with bloodwork, stool samples, and what to order and test beyond electrolytes, albumin, and so on based on the symptoms, so office staff can get the ball rolling before the physician sees the patient,” Dr. Cohen said.
From there, it's a matter of history, Dr. Cohen added, emphasizing the importance of basic questions. “You will never diagnose a single foodborne illness if you don't ask what patients ate. Have they eaten out? How recently? How do they prepare food at home? Have they traveled recently?”
If tests reveal a pathogen, treatment will be fairly obvious, but often enough, tests will come back negative, said Beth Kassanoff, MD, FACP, physician partner at North Texas Preferred Health Partners in Dallas at Baylor University Medical Center.
“Then we'll think about whether there is anything we could be missing. We might try an empiric antibiotic,” Dr. Kassanoff said, noting that such a measure is a judgment call and that primary care physicians should also consider the potential gastrointestinal effects of antibiotics, including creating an environment where Clostridium difficile can flourish.
Dr. Kassanoff added that sometimes parasitic infections don't show up right away on tests. “Then we have patients provide a stool sample once a day every day for 3 subsequent days.”
Regardless of the treatment, internists should follow up, Dr. Kassanoff said. “Sometimes patients won't call back to let you know something didn't work, so have a system in the office to follow up with patients a couple of days later.”
This will help internists ensure that complications don't develop. “If the illness is lingering longer than a week, the patient needs to be seen to check things like electrolytes, kidney function, and blood counts,” Dr. Kassanoff said.
Follow-up is particularly important for patients whose occupations put them in contact with the public, such as food workers, health care workers, and school and daycare workers, said Dr. Cohen. “It's one of your responsibilities to make sure they are not shedding [the pathogens] before they go back to work. If I pick up Salmonella, before I go back to work, I should have some negative cultures to demonstrate that I won't be ‘Typhoid Stu’ and pass it off to my patients.”
Most patients who are treated for foodborne pathogens recover well, but for some, complications ensue. The National Institute of Arthritis and Musculoskeletal and Skin Diseases notes that infections with Salmonella, Shigella, Yersinia, and Campylobacter species can trigger reactive arthritis. The U.S. Department of Health and Human Services notes that certain strains of Escherichia coli can lead to hemolytic-uremic syndrome, that Listeria infection can lead to meningitis, and that up to 40% of cases of Guillain-Barré syndrome in the U.S. may be triggered by an infection with Campylobacter.
The symptoms of hemolytic-uremic syndrome are usually severe enough to send a patient to the hospital, leading to a diagnosis there, but for the most part, physicians rely on patients to come forth and report symptoms of other conditions that may arise from foodborne illness, said Dr. Kassanoff. “Most cases of Guillain-Barré syndrome happen within about 12 weeks of the initial illness, and there is no screening or monitoring other than symptom reporting. Reactive arthritis is similar to Guillain-Barré syndrome in that we rely on patients to report their symptoms, as there is no testing to be done in the absence of symptoms. There is no specific amount of time after which we can say a patient is ‘safe’ from reactive arthritis.”
That some of these complications can turn up long after the immediate foodborne illness is gone points to the importance of the internist's role in managing the patient early on, said Dr. Kammeyer. “As far as long-term planning, where the internist is going to be most helpful is in making the correct initial diagnosis. For instance, if a patient develops signs of Guillain-Barré syndrome, the internist would be helpful in identifying that the patient could have had infection with Campylobacter [some time ago].”
Although complications should and would be managed by the appropriate subspecialists—for example, nephrologists managing patients with hemolytic-uremic syndrome—internists still play a role in the patient's care, said Dr. Kassanoff. “Patients rely on us as the physicians they know best, and we can help them figure out what questions to ask the specialists. They'll also call us when their specialists are hard to get on the phone. We can consult with the specialists ourselves.”
If complications are chronic, internists need to be aware of how the subspecialists are treating the patient, Dr. Kassanoff added. “At some point, specialists will release the patient back to the internist for long-term monitoring. We also need to watch for and monitor [side effects] of potent medication.”
‘But, doc …’
Patients who get the all-clear on pathogens and have no severe complications that need to be managed by a subspecialist can still suffer the after-effects of foodborne pathogens, said Jeffrey A. Abrams, MD, a gastroenterologist and clinical assistant professor at the Sidney Kimmel Medical College at Thomas Jefferson University in Philadelphia.
“When symptoms linger and not from persistent infection, the problem could be due to a change in gut function or change in bacterial intestinal flora. At that point, you need to consider postinfectious irritable bowel syndrome, gastroparesis, functional dyspepsia, and/or small intestinal bacterial overgrowth syndrome,” Dr. Abrams said.
He added that when persistent infection has been ruled out, the next step is treating and managing symptoms. “The particular symptoms, whether upper gastrointestinal symptoms with nausea or early satiety or lower gastrointestinal symptoms with discomfort pain and diarrhea, will dictate the treatment regimen,” he said. He noted that if symptoms persist, further work-up may also be needed.
Dr. Abrams reminded primary care physicians to be aware that treatment with certain medications may increase the risk of foodborne illness. For example, he noted, treatment with proton-pump inhibitors remove one line of defense by inhibiting acid. “Of course, immunosuppressant medications can also increase risk,” he said.
Some patients may be left with irritable bowel syndrome (IBS) in the wake of foodborne illness, but Dr. Kammeyer warned against tossing out that diagnosis without thorough investigation. “IBS can feel like a catch-all term [once other illnesses and conditions have been eliminated as possibilities], but IBS has been more rigorously defined and assigned more rigorous criteria than some years ago,” for example, with the May 2016 release of updated diagnosis criteria by the Rome Foundation.
As with conditions like Guillain-Barré syndrome and reactive arthritis, it's up to the patient to come forth with symptoms of IBS, said Dr. Kassanoff. “We don't have any tests or specific symptoms to tell us if it is related to foodborne illness, apart from the fact that patients who have [postinfection] IBS often don't feel that their initial illness symptoms ever completely resolve. We typically treat them the same way [we treat other IBS patients], except that we might not use certain medications like antidepressants because those take 4 to 6 weeks to kick in and for many of these patients, their symptoms would be better at that point. But it all depends on how bothered patients are by their symptoms and how aggressive they want to be.”
Dr. Kassanoff emphasized that internists can play a role in the day-to-day management of gastrointestinal symptoms after the patient has been treated for foodborne illness.
“We can help them with the secondary lactose malabsorption patients can have for a period of time [after foodborne illness] by working with them on their diet, and we can help patients with IBS by helping them work through an elimination diet,” said Dr. Kassanoff, referring to plans that restrict fermentable oligosaccharide, disaccharide, monosaccharide, and polyols in the diet, known as low-FODMAP diets.
As for the distant aftermath of foodborne illness, the science is still in its infancy, said Dr. Kammeyer. “We have a lot to understand yet in terms of the long-term effects of foodborne illness, and there will be a lot of new data in the coming years, so stay tuned.”