Pediatric Diarrhea: History is the Primary Diagnostic Tool
By Frederick Varone, MD and Meghan Beucher, MD
CASE
A 5 year-old healthy male presented to the emergency department with his father with a chief complaint of fever, diarrhea, and vomiting.
Fever was his first symptom. It started one week prior to presentation and was persistent over the course of the week. His highest temperature was 103.7 °F. Fevers occurred daily despite treatment with antipyretics. After his fever developed, he started having 4-5 daily episodes of watery diarrhea. Dad noted blood in the diarrhea only once. He complained of generalized abdominal pain when having bowel movements. He also had several episodes of nonbloody nonbilious vomiting over the first few days but this had resolved. His appetite was decreased and dad said he had only eaten one full meal in the three days prior to presentation. He had not urinated yet on the day of presentation.
Vital signs were notable for a heart rate of 120 and temperature of 101.5°F. Blood pressure and respiratory rate were normal for his age. Physical exam was notable for signs of dehydration – dry mucous membranes, prolonged capillary refill time – and a patient who simply appeared sick and tired. His abdomen was soft and nontender to deep palpation in all quadrants.
Labwork demonstrated mildly low sodium, potassium, chloride, and bicarbonate – consistent with dehydration. CRP and ESR were mildly elevated. CBC showed a normal white blood cell count and no anemia although platelets were elevated. Respiratory pathogen panel and urinalysis were negative. An extended Cary Blair stool panel returned positive for Salmonella species.
THE CATCH
This was the history, physical exam, and diagnostic evaluation that I obtained on my initial encounter with this patient. Predominant symptoms of diarrhea and fever as well as minimal abdominal pain and vomiting pointed me towards a possible infectious etiology of his symptoms. His abdominal exam was helpful in lowering my suspicion for an appendicitis given his lack of tenderness. Otherwise, his exam did not give me any further clues as to the underlying disease process. The prolonged course of 7 days of illness plus fever and an episode of bloody diarrhea prompted my suspicions for a bacterial infectious etiology – however, I had not asked all of the appropriate questions to explain why the patient may had an infection. The work-up explained what the patient had, but further history would explain why. We had already started IV fluid rehydration and antipyretic treatment, and we planned to admit the patient for dehydration.
THE SECOND HISTORY
Upon seeing that the patient’s stool tested positive for Salmonella species, I went back to the room to let dad know the results. He was surprised to hear this, and immediately asked if I thought the patient could have contracted Salmonella at a cookout the day prior to presentation. This was certainly suspect as the source of the patient’s exposure. Salmonella species are known to grow in a variety of foods including meat, eggs, and fruits and grow quickly in warm weather. Symptoms can start 6 hours after exposure, so this patient fell within the right time frame. On further questioning, dad and several other people at the cookout at all of the same foods as the patient and no one else became sick, which lowered my suspicion that the cookout is where he picked up the bacteria.
Digging into my previously (mostly) useless bank of knowledge from Steps 1, 2, and 3, I asked a very specific question that I had never asked a patient before: Do you have a turtle? Dad looked surprised, and told me that they had gotten a turtle a week before the patient’s symptoms had started. They were rehabilitating the turtle to be released into the wild, as they had rescued it when it was sick. Turtles and other reptiles are known reservoirs of Salmonella bacteria, as well as some bird species like chickens and turkeys. [2] We had our why!
DISCUSSION
Diarrhea is the presence of a higher amount of water in stool than normal, typically associated with more frequent bowel movements than what is normal for the patient although exact definitions differ by source. [4] Mechanistically, diarrhea is caused by either increased intestinal water secretion, decreased intestinal absorption, increased osmotic load, or abnormal intestinal motility. Clinically it often makes sense to separate diarrhea into the categories of infectious, inflammatory, structural, or malabsorptive to have a framework for your differential.
Diarrhea plus fever in the pediatric patient sets us down the infectious pathway. The most common cause of pediatric infectious diarrhea is viral infection, typically with rotavirus.[1] Dysentery – the presence of bloody diarrhea – should prompt you think about bacterial and inflammatory causes. In pediatrics, bacterial infections (Shigella, Salmonella, EHEC, Campylobacter, Yersinia, Vibrio, C. Difficile) and/or inflammatory bowel disease such as Crohn’s and ulcerative colitis need to be given strong consideration.
Diagnosing the cause of diarrhea is not always the most important thing we have to do. Often, pediatric patients present to the emergency department very well-appearing after one or two days of some watery diarrhea. Most of the time I don’t do any diagnostic work other than my history and physical exam – blood work and a stool PCR panel don’t change my management in an otherwise well-appearing child. The majority of children will improve without significant intervention other than supportive care and hydration at home. In the acutely ill, dehydrated and sick looking kid with a week of fever and bloody diarrhea, finding out the exact cause can be much more crucial.
A 2017 guideline published by the Infectious Disease Society of America for the diagnosis and management of diarrhea recommends testing for Salmonella, Shigella, Campylobacter, Yersinia, C. difficile, and STEC in people with diarrhea and fever, bloody or mucoid stools, severe abdominal cramping or tenderness, or signs of sepsis. They do not recommend empiric antibiotics in the setting of a presumed infectious diarrhea unless the patient is an infant less than 3 months of age with a suspected bacterial etiology, has a presumptive diagnosis of Shigella, or has recently travelled internationally and has a fever ≥38.5°F or signs of sepsis. If antibiotics are indicated, choose ceftriaxone as first line. Alternative agents include ciprofloxacin, ampicillin, amoxicillin, or TMP-SMX as alternatives. [5]
Species like Salmonella and Shigella are known to cause severe systemic illnesses include typhoid fever, sepsis, and spreading infections such as osteomyelitis. Infection with E. coli 0157:H7 can cause hemolytic uremic syndrome (HUS), which may present with similar symptoms and lead to kidney failure. While antibiotics are indicated in severe Salmonella infections, they lead to a higher chance of HUS and kidney failure in an E. coli 0157:H7 infection.
If I had known that this patient had adopted a turtle during my initial history, I could have had a clear idea of the full diagnosis with no other tests. The patient’s father planned to give the turtle to a friend to prevent future episodes. If I had not asked, they would have never known the likely source. Kids aren’t known to be terribly diligent with hand washing after handling pets. Of all human cases of Salmonella infection, 6% are attributed to reptile exposure – for patients under 21 years of age it’s 11%, certainly not a negligible number. [2] Most people don’t know that reptiles can be Salmonella carriers! Knowing the source of this bacteria hopefully prevented this patient from a second Salmonella infection.
I know that on busy days, my focus shifts and I find myself reducing my history and physical in favor of broad diagnostic studies hoping to find something to guide my disposition. While the patient may get where they need to go, I probably have not done my due diligence as a physician, public health champion, and patient advocate when I miss details. This case was a good reminder of my most important diagnostic test as a physician: taking a good history.
AUTHORS
Frederick Varone, MD is a third year emergency medicine resident at Brown University
Meghan Beucher, MD is an assistant professor in emergency medicine at Brown University
REFERENCES
Freedman SB, Thull-Freddman J. Vomiting, Diarrhea, and Dehydration in Infants and Children. In: Intinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. Mcgraw-Hill.
Harris JR, Bergmire-Sweat D, Schlegel JH et al. Multistate Outbreak of Salmonella Infections Associated with Small Turtle Exposure, 2007-2008. Pediatrics. 2009; 124(5) 1388-1394. doi: https://doi.org/10.1542/peds.2009-0272
Kman NE, Werman HA, Greenberger SM. Disorderes Presenting Primarily With Diarrhea. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. Mcgraw-Hill.
Pereira F, Hsu D. Diarrhea. In: Shaw K, Bachur RG, eds. Fleisher and Ludwig’s textbook of pediatric emergency medicine. 7th edition. Lippincott Williams & Wilkins, 2016.
Shane AL, Mody RK, Crump JA et al. 2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea. CID. 2017; 65(12) e45-e80. doi: https://doi.org/10.1093/cid/cix669.