CRACKCast E031 – Diarrhea

In CRACKCast, Podcast by Justin Roos2 Comments

This episode of CRACKCast covers Rosen’s Chapter 31, Diarrhea. This chapter covers a common ED complaint including the pathophysiology, risk factors for non-benign diarrhea, and the approach to treatment.

Shownotes – PDF Here


Rosen’s in Perspective

Runny poo accounts for 5% of all ED visits… or about 6 patients a week for the average provider. While in the developed world we associate diarrhea more with embarrassing road trip and first dates than a real health concern, worldwide diarrhea is responsible for 4% of ALL DEATHS. That’s equal to a 737 crashing and killing all on-board every 50 minutes for an entire year! There’s some food for squat… er… thought.


1) Define Acute, Persistent, Chronic Diarrhea

Diarrhea – Greek from dia (Through) and rhein (to flow)

Acute – 14 days or less (usually infectious viral or bacterial)

Persistent – 14 days or more (usually bacterial or protozoan)

Chronic – 30 days or more (usually non-infectious)


2) Describe 4 mechanisms of diarrhea

Rule of NUMBER 2 (POO): 2 fast, 2 strong, 2 broken, 2 confused

Too fast: Abnormal motility – hypermotility decreases contact time, limiting water and electrolyte absorption. Example, heroin withdrawal, also component of almost every acute diarrhea

Too strong: Osmotic diarrhea – highly osmotic solutes induce strong osmotic gradient favoring stool, overcoming transporter’s ability to absorb. Examples include laxatics and steatorrhea.

Too broken: Inflammatory diarrhea is caused by direct damage or toxicity to cells, decreasing the ability to absorb, examples include  chemo, rad, infection – continues despite fasting

Too confused: Cellular confusion by cytotoxic chemicals cause secretion rather than absoption, Ex. cholera


3) List 15 historical factors that increase the risk of probability of non-benign diarrhea

Coming at you straight outta Compton.. I mean straight outta Table 31, what are the so called ‘red-flags’ of diarrhea?

Lets break it down a little bit so the knowledge ‘flows’ a little better…

Location: Encounters with hospital system, travel, day care and wilderness

Exposure: Antibiotic exposure, strange animals (shellfish, farm animals, amphibians), sick amigos, known contaminated meats or dairy

Symptoms: Vomiting immediately after suspicious food, pain/n/v/blood/fever/tenesmus (my favorite work), more than a week of poops

Signs and labs: HUS (HGB < 80 with peripermal smear schistos and helmets, plt < 140, AKI), stool WBCs (not reliable), colonic ulcerations and pseudomembranes (I for one am doing sigmoidoscope on every large volume diarrhea….), proctitis

Patient factors: Immunecompromised (Organs, HIV, other)


4) What are the indications for empiric antibiotic treatment?

Direct from rosens: “Antibiotic treatment is initiated in patients with a suspected invasive process and severe diarrhea, systemic symptoms, fever, or abdominal pain and in patients who appear toxic.”

Clear as…well…. Mud? If you do decide to treat, Cipro 500 BID for 3-5d is recommended. Caveats apply to pregnant women as it crosses the placenta, and children under 18, who should only have supportive care initially until culture results as infection with ETEC can cause HHS and TTP


5) List 6 organisms that cause bloody diarrhea

“Clotty salty excrement screws your vitals”

Camplyobactor, Salmonella, EPEC, Shigella, Yersinia, Vibrio





1) When is Loperamide indicated?

Controversial, but generally accepted to be safe if no fever and non-bloody.

However, probably okay if combined with antibiotics in the fever/bloody diarrhea

Avoid in pediatrics (can provoke HUS, toxic megacolon)

Lactobacillius probiotics may also help with diarrhea and can be suggested


2) Who, what, when, when, why of stool cultures?

  • Ill-appearing
  • Immunocompromised (including young and old people)
  • Non-responders to treatment
  • Chronic course

Know that positive rate is about 2%, which is astronomically low!

Ova & Parasites?

  • Chronic, high risk locations
    -> Rosens is very specific with this one: Russia and Nepal
  • Exposure to infants in daycare (strangely non-specific)
  • HIV (+) patients

3) Best way to give children pedialyte?

It turns out we may not have to…

Recent study in JAMA by Freedman et al (Effect of Dilute Apple Juice and Preferred Fluids vs. Electrolyte Maintenance Solution on Treatment Failure Among Children With Mild Gastroenteritis)

Suggested that children with mild gastro who were given dilute juice had less treatment failure than electrolyte solution and required less IV fluid / hospitalization


This post was uploaded and copyedited by Colin Sedgwick (@colin_sedgwick)

Justin Roos

Justin Roos is an emergency medicine resident at the University of British Columbia. His interests include mountain and wilderness medicine. He is a contributor to the CrackCast podcast.

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