PBL 17 It comes back to haunt me
Rick Allen
Gastroenteritis
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Most common cause of acute gastrointestinal infection
CF: diarrhoea w/wo vomiting
Our way of thinking:
o Disturbed motility – hypermotility (resection or neural issue)
o Osmotic – osmotic drag (lactose)
o Malabsorbitive – blanketing. Linked to osmotic
o Exudative – inflam  pus, mucous, blood eg shigella and salmonella
o Secretion – excessive electrolyte/fluid excretion (cholera  ↑ Cl-)
Viral
o Norovirus – causes ~ 50% of outbreaks worldwide. Food/water, personto-person. Self limiting, short incubation. Infect mucosal cells.
o Rotavirus – most common for kids and diarrhoeal deaths. Selectively
infects and destroys small intestine enterocytes, leading to these areas
repopulated with immature secretory cells. ↓ Absorption, ↑ secretion
(osmotic)
o Adenovirus – 2nd most common for kiddies
Dysentery
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Dictionary meaning: “any of a variety of disorders marked by inflammation of the
intestines (especially the colon) combined with abdominal pain, tenesmus (straining or
ineffectual straining) and diarrhoea/increased bowel motions possibly containing blood
and/or mucous.”
Low volume bloody diarrhoea w. abdo pain
So basically could be any part of a lot of things. That’s all your getting from me.
Methods of causing diarrhoea (bacteria):
o Mucosal adherence – effacement of intestinal mucosa  mod. watery
diarrhoea eg. E. coli
o Mucosal invasion – penetration and destruction of mucosa  dysentery
eg. Shigella, campylobacter
o Toxin production
 Enterotoxin – cause fluid secretion wo mucosal damage 
profuse watery diarrhoea eg. Cholera. S. auereus and B. cereus
enterotoxin causes vomiting.
 Cytotoxin – damage the mucosa  dysentery eg. Salmonella,
campylobacter
Clinical syndromes can be used to differentiate bacterial causes
o Dysentery vs. watery stools
Examples
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Salmonella – many different types.Inc. 12-48hrs. Cause sx. via invasion and
enterotoxin. Large and small bowel. Can get fever. Self-limiting 3-6d. Can be
complicated by bacteremia and metastatic infection. Dx. Culture stool/blood. Tx.
AB may help, but not be needed.
Campylobacter – Most common enteric pathogen in developed countries (USA).
Undercooked meat. Inc. 2-4d. Self-limiting 3-5d. Dx. stool culture
PBL 17 It comes back to haunt me
Rick Allen
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Shigella – enterocyte invasion  macrophage invasion  inflam. Inc. 24-48 hrs.
DYSENTRY, fever. Self limiting 7-10d. AB. Humans only known reservoir.
E.coli – some nasty varients out there
Cholera – raw fish/shellfish. “explosive diarrhoea”. Activates CFTR channels 
Cl secretion  HCO3, H2O and Na into lumen
S.aureus – enterotoxin
Clostridium difficile – inc. 2d to 1 mth after AB use!!! Psuedomembranous colitis
(psuedomembrane: neutrophil, dead epithelial cells and inflam. debris) RF. 3rd
gen cephlasporins.
Whipple disease – bacteria ingested by macrophages which accumulate in
lamina propria + mesenteric lymph nodes  lymphatic obstruction 
malabsorptive diarrhoea.
Other
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Giardia lamblia, cryptosporidium (basically like giardia), entamoeba histolytica,
all types of worms (ascaris [nematode - round worm], cestodes [tapeworms],
schistosomiasis [trematode - blood fluke], pinworms, hookworms)
Prevention
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HYGIENE BITCHES!!!!
Stay clear of suspect food, water and people
Stay clear of day care facilities, institutions or homes for the mentally ill
Treatment
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Rehydration – either orally or via IV as appropriate
Ix. – blood/stool culture, stool toxins (difficile), electrolytes, urea.
AB as deemed suitable. May not always be necessary.
Determine the source
Notifiable disease?
Watch for pt. complications (septicaemia, renal failure, perforation)
AVOID anti-motility drugs.
PBL 17 It comes back to haunt me
Rick Allen
Management of chronic disease
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Chronic Disease
o Features: persistent, complex causality, multiple RF, insidious onset (not
always), not immediately life threatening (but complications may be)
o Dimensions:
 Disease = clinical. Anatomical/physiological manifestations
 Illness = social. Impact/response of interactions w family, friends,
co-workers, HCP, community. = Personal. Psychological, se;f
perception and the perception of others
o Pervasive uncertainty, no cure and ‘shared’ knowledge & expertise w Doc
Dealing with it
o Self management – gives a sense of control, confidence and
responsibility to the pt., keeps them involved in the decision making
process, gives them ownership. Increases efficacy and adherence.
o Communication/partnerships with HCP
o Focus beyond the condition – look at health promotion and lifestyle.
Peoples capacity to manage chronic illness involves:
o Individual factors: willpower, age, education, finance, attitude, beliefs…
o Doc/HCP: approach
o Family and friends: level of influence and support
o Community organisations: self-help, peer support, role models
o Work colleagues: support and acceptance
o Community: support services, transport, attitude
o Media/policy: information, laws, access to services, discrimination
Docs role
o Collaboratively defined probs: Doc and pt view.
o Goal setting and planning: realistic considering pt. current position
o Organise or assist with support services or education/training for effective
self management
o Active follow-up: specified intervals, monitor, reinforce progress.