Course:PostgradFamilyPractice/ExamPrep/99 Priority Topics/Diarrhea

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Diarrhea - Key Features

1. In all patients with diarrhea,
a) Determine hydration status:

-heart rate, BP, orthostatic vital signs, mucous membranes, skin turgor, urine output, capillary refill time, eyes, fontanelle (peds), production tears (peds)

b) Treat dehydration appropriately.

-mild-moderate dehydration: trial of PO rehydration
-Severe or failure of PO rehdration: IV fluid therapy – NS or RL bolus

2. In patients with acute diarrhea, use history to establish the possible aetiology (e.g., infectious contacts, travel, recent antibiotic or other medication use, common eating place for multiple ill patients).

Note: acute diarrhea is < 14days duration

Infectious etiology:
• Bacterial: shigella, salmonella, campylobacter, yersinia, ecoli, clostridium, vibrio, staph aureus, bacillus cereus
• Viral: norovirus, rotavirus, adenovirus, CMV, HSV
• Parasitic: cryptosporidium, microsporidia, entamoeba histolytica, giardia lamblia, cyclospora

Medications: Antibiotics, colchicine, laxatives, magnesium containing antacids

Food Intolerance: Lactose, fructose in soft drinks, sorbital, coffee

Intestinal Diseases (acute episodes): Celiac, inflammatory bowel dz

Clues from hx regarding specific cause:

• presence of fever, bloody diarrhea and tenesmes suggest inflammatory diarrhea (eg. Shigella, salmonella, campylobacter, c diff colitis or IBD)
• Consider norovirus with classic history of nausea, vomiting, intense cramping, and watery diarrhea that usually lasts 48-72 hrs
• Travelers diarrhea is most commonly caused by enterotoxogenic E. Coli, but still consider other causes of diarrhea and specific organisms based on area of travel
• Exposure to contaminated water or camping think of parasites (giardia, cryptosporidium and entamoeba)
• Exposure to animals: Young cats/dogs → campylobacter; Turtles → Salmonella
• Organisms that cause food poisonings:
o Dairy food -Campylobacter and Salmonella species; Eggs -Salmonella species
o Ground beef - Enterohemorrhagic E coli
o Poultry -Campylobacter species
o Pork -C perfringens, Y enterocolitica
o Seafood - Astrovirus and Aeromonas, Plesiomonas, and Vibrio species
o Oysters - Calicivirus and Plesiomonas and Vibrio species
o Vegetables -Aeromonas species and C perfringens

3. In patients with acute diarrhea who have had recent hospitalization or recent antibiotic use, look for clostridium difficile.

• Suspect if antibiotic use within the last 2 months or discharge from hospital within last 72 hours; can happen with almost all antibiotics (although clinda is the classical example). Presents with watery diarrhea that is rarely bloody, crampy abdo pain, malaise, fever, anorexia.
• Can lead to fulminant colitis and toxic megacolon

4. In patients with acute diarrhea, counsel about the timing of return to work/school (re: the likelihood of infectivity).

• No return to work until no diarrhea for at least 48 hours
• Food handlers/daycare workers/health care workers may require negative stool samples on 2 occasions at least 24 hrs apart prior to returning to work to prevent outbreaks

5. Pursue investigation, in a timely manner, of elderly with unexplained diarrhea, as they are more likely to have pathology.

• Any change in bowel habit should raise possibility of colorectal cancer
• Also consider other pathology such as diverticulitis, inflammatory bowel disease, etc.

6. In a young person with chronic or recurrent diarrhea, with no red flag symptoms or signs, use established clinical criteria to make a positive diagnosis of irritable bowel syndrome (do not over investigate).

• Red flags: fevers/chills, weight loss, bloody stool, mucousy stool, nocturnal diarrhea, large volume stool, greasy stool, FHx of IBD or cancer, anemia, persistent daily diarrhea or constipation, severe pain

• Rome III criteria:

o Recurrent abdominal pain or discomfort for at least 3 days per month in the last 3 months associated with 2 or more of the following:
• Improvement with defecation
• Onset associated with a change in frequency of stool
• Onset associated with a change in form (appearance of stool)
o criteria fulfilled for the last 3 mths with sx onset at least 6 mths prior to dx
o Supportive sxs that are not part of the diagnostic criteria include:
• a) <3 BM/week, b) >3BM/day or abnormal stool form c) lumpy/hard stool d) loose/watery stool e) defecation straining f) urgency or feeling of incomplete bowel movement, passing mucus or bloating
o in the absence of structural or metabolic abnormalities to explain the sxs
o “discomfort” means an uncomfortable sensation not described as pain

7. In patients with chronic or recurrent diarrhea, look for both gastro-intestinal and non-gastro-intestinal symptoms and signs suggestive of specific diseases

• Malabsorption Syndrome:

o Stool tend to be pale, greasy, voluminous, and foul-smelling
o Patients typically have weight loss despite adequate food intake
o Common disorders with malabsorption include: Lactose intolerance, chronic pancreatitis, Celiac disease, Bacterial overgrowth of the small intestine

• Cholecystecomy:

o Reported in 5-12% of patients following cholecystectomy, due to excessive bile salts entering the colon
o Usually resolves spontaneously over the course of weeks to months
o Can be treated with cholestryamine

• Inflammatory Bowel Disease: crohn’s and ulcerative colitis

o Age on onset typically between 15 and 40, but may have a second peak between 50 to 80
o Extraintestinal manifestions: iritis/uveitis, arthritis, skin changes, aphthous stomatitis, nail changes, pericholangitis, and sclerosing cholangitis
o Need to monitor for cancerous changes in colon
o Crohn’s:
• present with abdo pain, diarrhea, weight loss and fever; hemoccult positive stools are common, macroscopic bleeding less common
• Can get inflammation anywhere along GI tract (“from gums to bum”) in discontinuous fashion
• Inflammation is transmural therefore commonly get fistula formation
o Ulcerative colitis:
• Only involves colon, always starting distally and ascends in continuous manner
• Variable presentation depending on extent of disease, typically presents with bloody diarrhea, fever, weight loss

Study Guide



Wanke, CA. (2011). Approach to the adult with acute diarrhea in developed countries. In D.S. Basow (Ed.), UpToDate. Retrieved from

Bonis, PA and LaMont, JT. (2011). Approach to the adult with chronic diarrhea in developed countries. In D.S. Basow (Ed.), UpToDate. Retrieved from

Aberra, FN (2011). Clostridium difficile colitis. Retrieved from

Guandalini, A. (2010). Diarrhea. Retrieved from

Rowe. WA (2011). Inflammatory bowel disease. Retrieved from

Therapeutic Choices Sixth edition. Ottawa, Canadian Pharmacists Association. 2011.