HTHSCI 2HH3 Lecture Notes - Lecture 8: Chemotherapy, Neutrophil, Cholera
26 May 2018
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Infections of the GI System
Campylobacter jejuni
Salmonella enterica
Gastroenteritis
• Inflammatory process of the stomach or intestinal mucosal surface
• Commonly associated with ingestion of contaminated foods and/or contaminated water
• 4 million Canadians suffer from food-related illness per year
Infection
• Pathogen enters gastrointestinal tract and multiplies
• Delay in appearance of gastrointestinal symptoms (generally 1 – 3 days), while pathogen
increases in number or damages invaded tissue
• Associated with fever
Intoxication
• Associated with the ingestion of preformed toxin EXOtoxin (inside cell)
• Does’t need to adhere and penetrate to cause damage to the host defenses (no lag
phase)
• Characterized by a sudden appearance of symptoms
o 2 – 10 hours after consumption of the toxin
• Fever rarely a symptom
Gastrointestinal infections and intoxications cause acute diarrhea
• Increased frequency of stools (more than 3 bowel movements per day)
• Increased stool volume (> 200mL of fluid/day excreted in feces)
• Stools take the shape of their container
Gastroenteritis
• Abdominal pain/cramping
• Nausea and vomiting
• Dehydration
• Weight loss
• Fever (intoxication- no fever, infection- fever)
Acute diarrhea (< 2 weeks) divided into 3 clinical syndromes
1. Non-inflammatory
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2. Inflammatory
a. Invasive
Non-inflammatory (secretory) diarrhea
• Most common diarrheal syndrome in North America
• Typically caused by viruses: Norovirus, rotavirus
• More severe attacks caused by bacteria:
o Enterotoxigenic E. coli, Vibrio Cholera traelers’ diarrhea
• Associated with some parasites: Giardia intestinalis
• Characterized by infection of the small intestine leading to large volumes of watery
diarrhea
o Absence of fecal leukocytes (why it is non-inflammatory)
Inflammatory diarrhea
• Caused by bacteria
o Shigella spp., Salmonella enterica, Campylobacter jejuni
• Associated with some parasites
• Characterized by an infection of the colon, causing frequent, small volume loose stools
o Blood (gross or occult) often present
o Presence of fecal leukocytes and mucous
Dysentery: Specific term referring to severe diarrhea containing visible blood and often mucous
and/or pus
Invasive diarrhea
Subset of inflammatory diarrhea associated with an invasion of the, and increased risk of
bacteremia
• Caused by bacteria
• Salmonella spp., Verocytotoxin-producing E. coli
• Associated with some parasites
• Invasive microbes in the epithelial lining of the gut, especially dangerous if it is able to
move to the bloodstream
Gastroenteritis
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Physician consultation advised in all patients with any of the following symptoms
• Fever (> 38.5°C)
• Dysentery
• Significant abdominal pain
• Dehydration
Initial evaluation should include
• Patient history, physical exam and screening stool examination
Further laboratory testing and antimicrobial therapy warranted for specific patients, based on
results of initial evaluation
Screening tool: allos HCP to ko if it’s ifetio or itoiatio
Antibiotic: can target and weaken our normal flora which is why it should be used sparingly with
the GI tract
• Intoxication
• Infection
o Inflammatory
▪ invasive
o non-inflammatory
Patient history
• Focus on disease severity & risk factors for significant disease
• Symptom duration, fever, abdominal pain, nausea, vomiting, and dehydration
o Description of diarrhea especially important
• Frequency, volume, visible blood, pus or mucous
• Investigate potential for common source outbreak
o Inquire about friends and relatives with similar symptoms
Gastroenteritis
Short incubation periods suggest ingestion of preformed toxin
Staphylococcal food poisoning 2 – 4 hours
C. perfringens food poisoning 10 – 24 hours
Norwalk virus 12 – 48 hours
Salmonellosis 8 – 18 hours
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Document Summary
Inflammatory process of the stomach or intestinal mucosal surface: commonly associated with ingestion of contaminated foods and/or contaminated water, 4 million canadians suffer from food-related illness per year. Infection: pathogen enters gastrointestinal tract and multiplies, delay in appearance of gastrointestinal symptoms (generally 1 3 days), while pathogen increases in number or damages invaded tissue, associated with fever. Intoxication: associated with the ingestion of preformed toxin exotoxin (inside cell, does(cid:374)"t need to adhere and penetrate to cause damage to the host defenses (no lag phase, characterized by a sudden appearance of symptoms. 2 10 hours after consumption of the toxin: fever rarely a symptom. Increased frequency of stools (more than 3 bowel movements per day: stools take the shape of their container. Increased stool volume (> 200ml of fluid/day excreted in feces) Gastroenteritis: abdominal pain/cramping, nausea and vomiting, dehydration, weight loss, fever (intoxication- no fever, infection- fever) Acute diarrhea (< 2 weeks) divided into 3 clinical syndromes: non-inflammatory, inflammatory, invasive.
