You are working a shift in the urgent care when you grab the next chart, a 34 year old male with one day history of bloody diarrhea. As you prepare to enter the room, you brief the medical student you are with, on the possible causes of both inflammatory and non-inflammatory diarrhea.
Upon speaking with the nurse, you find the patient’s vital signs are stable: pulse is 102, blood pressure 110/68, respirations 14, temperature 100.1 F. The intake form states the patient has had one day of very loose, bloody diarrhea without an inciting event such as travel, new medication, or recent illness. As you prepare to go into the room, you realize that the case itself has the potential for many good teaching points with the student.
Upon taking the history, you find that the onset of diarrhea began last evening. The patient reports no provoking factors. His diet has been similar to previous. He has not tried anything over the counter such as Immodium. He denies any abdominal pain, but does state that his abdomen feels “sore”. The timing of the diarrhea has been fairly consistent, about every hour for the past twelve hours. He reports greater than 10 loose, bloody bowel movements over the past 12 hours. He rates the diarrhea as “severe” and “unlike anything I’ve ever seen”. He is clearly very stressed about his acute illness, and you provide some reassurance.
There is no accompanying chest pain, palpitations, difficulty breathing, hematuria, fever, chills, headache, confusion, skin rash, joint pains. The patient reports that there have been no sick contacts. He has not had any recent travel. He has no family history of inflammatory bowel disease that he is aware of. He has no recent hospitalizations or antibiotic use. He is a current every day smoker, but trying to quit. He drinks alcohol occasionally and denies drug use.
Although sometimes uncomfortable to discuss, you spend a few minutes of the visit specifically discussing the patient’s diarrhea. He tells you that prior to last evening, he had had regular bowel movements. There is no history of previous diarrhea, let alone bloody diarrhea. The diarrhea itself is foul smelling, but has no mucus. It is “loose”, but “not watery”.The blood is bright red and is on the stool itself. The patient denies any history of hemorrhoids or anal fissure.
The patient tells you at the end of your history that, “This probably doesn’t make a difference”, but that about two days prior, he ate breakfast at a local diner. The patient states that he had an omelet that was “a little undercooked”. He did not feel poorly after eating this.
On exam, you re-reference his vital signs. There are no red flags that could indicate dehydration. His HEENT example is unremarkable, no oral lesions. There is no lymphadenopathy in the neck. His heart rate is tachycardic yet regular and his lungs are clear. His abdominal exam is notable for hyperactive bowel sounds and mild tenderness throughout the abdomen. His skin exam shows no delayed capillary refill. His neurologic exam is intact.
Before you explain the potential diagnosis and plan to the patient, you take some time to ask your student some questions. Obviously, just based on clinical exam, it is not possible to make a specific diagnosis. The differential remains somewhat broad, including infectious, inflammatory, immunologic, and much more. You come up with the following questions:
• What features, if present in the history, could indicate Clostridium difficile?
• What features, if present in the history, could indicate IBD?
• What features, if present in the history, could point toward a Giardia infection?
For the students reading the article, I would suggest that you work through each of the questions on your own prior to continuing to read the article. We will have the answers at the end!
Next, you direct your plan to the patient. You tell him that given the acute onset and blood, you suspect that this may be an infectious cause. You are suspicious of the omelet that he consumed just days prior. You discuss with the patient that at this point, you will hold off on any anti-biotics and suggest getting a stool culture. You remind the patient to drink plenty of fluids and AVOID over the counter anti-motility drugs. The next day, you discuss with your colleague who received the results after your shift: your patient’s stool was positive for salmonella.
Salmonella gastroenteritis is caused by a gram negative bacillus called Salmonella enterica (Prakash et al, 2016). There can be thousands of sub-types. Approximately 42,000 cases are reported to the CDC each year. The disease peaks between July and November and is one of the major bacterial causes of traveler’s diarrhea in the United States.
Etiology includes food causes such as contaminated poultry, beef, eggs, tomatoes, water, or prepared nuts. It can also be spread via the fecal oral route or contact with a chronic carrier. A notable cause of Salmonella diarrhea that is commonly tested includes exotic pets such as reptiles and turtles.
Possible risk factors include recent travel, contact with contaminated food as above, reptile as a pet, use of PPIs, previous gastric bypass.
Prevention includes vigorous hand washing, proper cooking to recommended temperature, refrigeration of eggs, and avoiding contact with animal feces.
Once ingested, the incubation period is usually 12 to 72 hours. As discussed above, there may be a history of eating undercooked poultry or eggs. Symptoms can include rapid onset of nausea, vomiting, diarrhea, abdominal pain, headache, and fever. On physical exam, there is commonly fever, dehydration, abdominal tenderness, and guaiac positive stool.
The diagnosis can be made via a stool culture. Other causes of infectious diarrhea such as E. Coli 0157, Shigella, and Campylobacter should be ruled out. In the very ill patient, blood cultures may be necessary. Other inpatient labs could include a CBC to measure leukocytosis or a CMP to indicate electrolyte balance.
The treatment for Salmonella gastroenteritis is largely supportive. The vast majority of patients will have a self-limited illness. In identified cases, the clinician or lab director should assure reporting to the CDC to track outbreaks. Vigorous hydration and electrolyte support is key. Anti-motility drugs are contraindicated as they can worsen the course.
In those with immunocompromised state, geriatric patients, or young pediatric patients, care should be taken to watch for bacteremia. These patients may benefit from anti-biotics, as they can be at risk for systemic infection. Reasonable anti-biotics include Levaquin, azithromycin, amoxicillin, ceftriaxone. Patients with severe infection, bacteremia, or signs of overt dehydration should be admitted to the hospital.
General prevention of further disease is paramount. Patients should be educated about properly handling meat, poultry, and eggs. Food should be cooked properly and thoroughly to kill Salmonella spores. Patients with reptilian pets should be cautious and practice vigorous hand washing.
As discussed above, there are many pearls here in the case presentation as well as regarding Salmonella in general. In reference to our questions from previous, one would note more watery diarrhea and possibly a history of anti-biotic use or health care exposure with Clostidium Difficile infection. In patients with IBD, there usually is a longer duration of bloody diarrhea and can be accompanied by joint pains, skin rash, visual changes such as scleritis, in the setting of a positive family history. Giardia infections can be from drinking in streams and may be accompanied by sulfur smelling burps.
Prakash, P. et al (2016). Salmonella Infection. The 5 Minute Clinical Consult.
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