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Toronto Notes 2019
Small and Large Bowel
Gastroenterology G15
Acute Diarrhea
Definition
• passageoffrequentunformedstoolsfor<14d
Etiology
• mostcommonlyduetoinfections
• mostinfectionsareself-limitingandresolvewithin7d
Risk Factors
• food(raworundercookedmeatandseafood,unpasteurizeddairyproducts)
• medications: antibiotics, laxatives
• others:highrisksexualactivity,infectiousoutbreaks,occupationalexposures(daycareworkers),family
Useful Questions in Acute Diarrhea
Those Fads Wilt Travel
Homosexual contacts Outbreaks
Seafood
Extra-intestinal signs of IBD Family history
Antibiotics
Diet
Steatorrhea
Weight loss Immunosuppressed Laxatives
Tumour history
Infectious Causes of Inflammatory Diarrhea Your Stool Smells Extremely Crappy
Yersinia
Shigella
Salmonella
E. coli (EHEC 0157:H7), E. histolytica Campylobacter, C. difficile
history (IBD)
Table 8. Classification of Acute Diarrhea
Definition Site Mechanism
Sigmoidoscopy Symptoms
Investigations Etiology
Differential Diagnosis
Significance
Investigations
Inflammatory
Disruption of intestinal mucosa Usually colon
Organisms and cytotoxins invade mucosa, killing mucosal cells, and further perpetuating the diarrhea
Usually abnormal mucosa seen
Bloody (not always)
Small volume, high frequency
Often lower abdominal cramping with urgency ± tenesmus
May have fever ± shock
Fecal WBC and RBC positive
See Differential Diagnosis of Presenting Complaints, G4
Acute presentation of idiopathic inflammatory bowel disease
Higher yield with stool C&S
Can progress to life-threatening megacolon, perforation, hemorrhage
Antibiotics may benefit
Non-Inflammatory
Intestinal mucosa intact Usually small intestine
Stimulation of intestinal water secretion and inhibition of water absorption (i.e. secretory problem)
Usually normal
Watery, little or no blood
Large volume
Upper/periumbilical pain/cramp ± shock
Fecal WBC negative
See Differential Diagnosis of Presenting Complaints, G4
Acute presentation of non-inflammatory chronic diarrhea (e.g. celiac disease)
Lower yield with stool C&S
Chief life-threatening problem is electrolyte disturbances/ fluid depletion
Antibiotics unlikely to be helpful
• stoolcultures/microscopy(C&S/O&P)arerequiredonlyifdiarrheaisinflammatory,severe,or for epidemiological purposes (day care worker, nursing home resident, community outbreaks, e.g. Walkerton, etc.)
■ C&S only tests Campylobacter, Salmonella, Shigella, E. coli ◆ other organisms must be ordered separately
• flexiblesigmoidoscopy(withoutbowelpreparation):usefulifinflammatorydiarrheasuspected
■ biopsies are the most useful method of distinguishing idiopathic IBD (Crohn’s disease and ulcerative
colitis) from infectious colitis or acute self-limited colitis
• C. difficile toxin: indicated when recent/remote antibiotic use, hospitalization, nursing home, or recent
chemotherapy
Treatment
• fluidandelectrolytereplacementorallyinmostcases,intravenousifsevereextremesofage/coma • anti-diarrheals
■ antimotility agents: diphenoxylate, loperamide (Imodium®); contraindicated in mucosal inflammation
◆ side effects: abdominal cramps, toxic megacolon
■ absorbants: kaolin/pectin (Kaopectate®), methylcellulose, activated attapulgite
◆ act by absorbing intestinal toxins/micro-organisms, or by coating intestinal mucosa
◆ much less effective than antimotility agents
■ modifiers of fluid transport: bismuth subsalicylate (Pepto-Bismol®) may be helpful (but should not
be used in the presence of bloody diarrhea or fever) • antibiotics:rarelyindicated
■ risks
◆ prolonged excretion of enteric pathogen (especially Salmonella) ◆ drug side effects (including C. difficile infection)
◆ development of resistant strains
◆ renal failure/hemolysis (enterohemorrhagic E. coli O157:H7)
Finally: A Role for Bacteriotherapy
Duodenal Infusion of Donor Feces for Recurrent Clostridium difficile
NEJM 2013; 368:407-15
For centuries, out-of-the-box thinkers have speculated that the colonic bacteria all of us have, but which differs among individuals, play a role in disease. More recently, the colonic microbiome has become the hottest area of research in gastroenterology. The best documented medical indication for manipulating the colonic bacteria is recurrent C. difficile infection. In this randomized study of this disease, infusion of donor feces via
a nasoduodenal tube resolved diarrhea in 81% of patients, without side-effects, compared to 31% given the standard treatment of oral vancomycin, and 23% of patients given oral vancomycin plus bowel lavage. It takes little prescience to predict an onslaught of future studies investigating
the therapeutic potential of altering the human microbiome.