Ep 162: A 73-Year-Old Woman with Fever and Altered Mental Status

This episode discusses a particular cause of sepsis and its treatment following a foodborne illness.

Read more on this topic in Harrison's.

Harrison's Principles of Internal Medicine, 22nd Edition

Transcript

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[Ms. Heidhausen] This is Katerina Heidhausen, executive editor of Harrison's Principles of Internal Medicine. Harrison's Podclass is brought to you by McGraw Hill's AccessMedicine, the online medical resource that delivers the latest content from the best minds in medicine. And now, on to the episode. 

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[Dr. Handy] Hi everyone, welcome back to Harrison's Podclass. We're your co-hosts. I'm Dr. Cathy Handy. 

[Dr. Wiener] And I'm Dr. Charlie Wiener, and we're joining you from the Johns Hopkins School of Medicine. Welcome to today's podclass, a 73-year-old woman with fever and altered mental status. Cathy, today's patient is a 73-year-old grandmother who's brought to the emergency department with fever and altered mental status. Her blood pressure in the ED is found to be 85/60 with a heart rate of 110. She's febrile to 102 degrees Fahrenheit with normal oxygen saturation. She's only oriented to person but has no focal, neurologic, cardiovascular, pulmonary, abdominal, or skin findings. 

[Dr. Handy] All right, fever, hypotension, tachycardia, that sounds like sepsis. We would start her volume resuscitation, send some labs, cultures, and maybe get some more history, but we should start antibiotics promptly, too. 

[Dr. Wiener] So talking to her family, they tell you that she's generally well and active. She lives with her daughter, son-in-law, and their three children who are ages four through ten. Her past medical history is only notable for some osteoarthritis, and in fact, her only medication is PRN ibuprofen. 

[Dr. Handy] All right, so she's not immunosuppressed. What's been going on lately, and has she traveled? Also, what time of year is it? 

[Dr. Wiener] It's winter, she lives in suburban Maryland, and has not left the country in the last two years. On a complete review of systems, the only notable finding is that about 10 days ago, most of the family, including the patient, had an acute gastroenteritis with fever, fatigue, and diarrhea that lasted one to three days after a meal of taco salads. The patient has been feeling fatigued, but everybody else felt better. 

[Dr. Handy] All right, that was helpful. So now we're leaning towards a febrile gastrointestinal illness that affected the patient but not the other family members for this prolonged course. So maybe something more common in the elderly. 

[Dr. Wiener] That gets us to our question, which is asking, which of the following is the most likely effective antibiotic for this patient? And the options are A. intravenous acyclovir; B. intravenous ampicillin; C. intravenous ceftriaxone; D. intravenous doxycycline; or E. oral vancomycin. 

[Dr. Handy] Okay, so let me rule out a few of the choices first. First, IV acyclovir would not be indicated even if this was a viral gastroenteritis. We can also eliminate oral vancomycin. That's a treatment for C. diff, but that seems unlikely given her history and not having any recent antibiotic use. Lastly, we can also rule out doxycycline, which is used more for most of the tick-borne illnesses, such as Lyme or Rocky Mountain spotted fever, but this is the wrong time of year, and again, the history is not suggestive. 

[Dr. Wiener] Okay, so you've left us with IV ceftriaxone and IV ampicillin. 

[Dr. Handy] Okay, let's think about the most likely infection. With her symptoms of fever, diarrhea, and fatigue that only lasted a couple days after a meal where everyone was sick, this is likely Listeria, and given her acute presentation now, I'd be concerned that she has invasive Listeria and is bacteremic. I think that the taco salad was probably the culprit. 

[Dr. Wiener] Why do you say that? 

[Dr. Handy] Listeria transmission is almost always foodborne, and it's a substantial contributor to deaths from foodborne illness despite being a relatively uncommon cause of illness. Hot dogs and deli meats were the major sources of US outbreaks until 2002 when an outbreak linked to turkey deli meat resulted in eight deaths and the recall of over 30 million pounds of meat. After that outbreak, the US Department of Agriculture's Food Safety and Inspection Service issued new regulations and intensified testing for Listeria in ready-to-eat meat and poultry plants, and producers added growth inhibitors. Since then, these products have rarely been implicated in outbreaks, yet the incidence of listeriosis has not declined significantly in about two decades. Dairy products are an important source, especially soft cheeses made with raw and pasteurized milk or produced from pasteurized milk in unsanitary facilities. Raw produce is another important source. Outbreaks have been traced to packaged salads, fruits, and sprouts. 

[Dr. Wiener] Our patient has no obvious risks, is that typical? 

[Dr. Handy] Most patients with invasive listeriosis are older adults, whose risk increases with each decade over 59 years of age. Most other patients have impaired cellular immunity associated with either hematologic malignancy, transplantation, HIV infection, or receipt of glucocorticoid or other immunosuppressive drugs. The group at highest risk is pregnant women, who almost always have only mild flu-like symptoms, but who transmit the infection to the fetus through the placenta. 

[Dr. Wiener] How does Listeria present clinically? 

[Dr. Handy] Most commonly, it's a febrile gastroenteritis that likely follows a large ingested inoculum. As occurred in this family, the usual symptoms are fever, diarrhea, headache, and constitutional symptoms. The illness is usually self-limited with symptoms lasting an average of one to three days. 

[Dr. Wiener] But this patient is even farther out than the rest of her family. What's going on here? 

[Dr. Handy] Some patients may develop disseminated disease with bacteremia, and that often occurs about ten days after the initial inoculation. Bacteremia can cause neurolisteriosis or localized infection at other sites. In a large French cohort study, the three month mortality rate for Listeria bacteremia was 46%. Death was associated with older age, female sex, neoplasia, multiorgan failure, worsening of preexisting organ dysfunction, and monocytopenia. Also, Listeria has an affinity for the central nervous system and neurolisteriosis or Listeria meningitis may complicate disseminated Listeria infection. 

[Dr. Wiener] Okay, I'm with you that she's presenting with disseminated Listeria, but the question's asking, how do we treat it now? 

[Dr. Handy] Well, Listeria treatment has not been evaluated in clinical trials, so recommendations are based on in vitro animal studies and observational clinical data. High-dose ampicillin or penicillin G is first-line therapy. So the answer is B. Because penicillins are only weakly bactericidal against Listeria, many experts recommend adding Gentamicin for synergy, particularly if the infection is severe. It is important to know that cephalosporins are not effective for Listeria, so option C. is not correct. 

[Dr. Wiener] Great, so the teaching points in today's case are that Listeria monocytogenes is a food-borne illness that can present with an acute self-limited gastroenteritis, but may evolve to a disseminated infection presenting with sepsis or meningitis. The treatment is with ampicillin or penicillin, often combined with gentamicin, cephalosporins are not effective. Also, we should note that listeriosis is a nationally notifiable disease in the United States. 

[Dr. Handy] You can find this question and other questions like it in the Harrison's Self-Review book, and you can learn more about this topic in the Harrison's chapter on Listeria monocytogenes infections. Visit the show notes for links to helpful resources, including related chapters and review questions from Harrison's, available exclusively on AccessMedicine. If you enjoyed this episode, please leave us a review, so we can reach more listeners just like you. Thanks so much for listening. 

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