Transcript Document

Hard Facts About Loose
Stool
Persistent Diarrhoea in the
Returned Traveller
Stan Houston
Dep’t of Medicine & School of
Public Health, U of Alberta
Objectives: Persistent Diarrhoea
 A subset,
generally a complication, of
“regular” acute travellers diarrhoea
 What is it? (arbitrarily, duration > 30 days)
 Who gets it?
 What causes it?
 What investigations are appropriate?
 How should we manage it?
Why Talk About
Persistent Diarrhoea?
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It is not uncommon
 It is a significant challenge when it occurs
 We are getting a handle on acute, “garden
variety” travellers’ diarrhoea
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Very common
Mainly food borne
Usually bacterial (? Role of norovirus)
Realistic expectations
Practical strategies
We are learning more about persistent diarrhoea
Persistent Diarrhea Post-Travel
Differential Diagnosis
“Typical” protozoan cause (E. histolytica, G. lamblia)
 Atypical presentation of “acute” pathogens, e.g.
Shigella
 Newer pathogens: Cyclospora, Cryptosporidia,
Dientameba fragilis
 ?Lactose intolerance
 Clostridium difficile diarrhea (antibiotic-related)
 “Unmasked” inflammatory bowel disease (IBD) or
celiac disease
 Tropical sprue
 HIV-related
 Post infectious irritable bowel
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• Helminths (worms or flukes) rarely cause diarrhea in travellers
Case 1.
 38
y.o. man returned from living in Mexico
with a history of intermittent bloody,
mucusy diarrhoea over a period of
months.
 Multiple stool exams for everything,
specifically amebiasis, negative
 Colonoscopy when he had been
asymptomatic for some time…negative
The doctor has to be persistent too
 Physical
examination unremarkable
 Stool examinations negative
 Repeat colonoscopy showed ulcerative
colitis (and biopsies confirmed absence of
ameba)
 Responded well to standard therapy
Case 2. 33 y.o. alternative medicine
enthusiast,
 Persistent
diarrhoea on return from Yemen
 Large volume, minimal pain, occasionally
nocturnal
 20 lb. weight loss*
 I was hoping for my first case of tropical
sprue!
Case 2, cont’d
 Small
bowel biopsy: celiac disease
(serology positive)
 Responded to celiac diet
Unmasked disease
 Inflammatory
bowel disease
 Celiac disease
 ? Lactose intolerance, irritable bowel
syndrome
Tropical sprue
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Much discussed in the era of the British empire
and the wars of the first half of the 20th century
Persistent malabsorption syndrome acquired in
the tropics
Epidemiology unclear or inconsistent
Thought to be mediated by bacterial overgrowth
in small intestine
Rx: antibiotics & folate
Rarely if ever seen now
Family Doc in her 30’s
 Went
to Chad as a missionary
 Within 48 hrs. of arrival, her kids got very
sick with febrile diarrhea, improved with
cotrimoxazole
 3 wks later she got sick
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Cramps “worse than labour”
In bed X 10 days
Tenesmus, some blood & mucus
For the next 10 months
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Diarrhea persisted, waxed & waned, never
resolved
Experienced severe urgency & incontinence
Lost 9 kg
Had amebiasis diagnosed in a Chadian lab, Rx
with no benefit
Cultures negative in Burkino Faso & Nairobi
Never took antibiotics!
In Canada, 1 culture negative
So of course, she was scoped
Chadian
Diarrhea
Endoscopic Diagnosis
 Definite
IBD
 Given a prescription for Asacol
 A report was received
 2nd
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specimen: Shigella flexneri serotype 1.
R Amp, S TMPSMX, S ciproflox
Course
 Rx:
ciprofloxacin 500 bid X 14
 Better within days, rapidly returned to
normal health, stool habit and weight, fine
since.
Common bugs behaving
uncommonly
 Shigella
normally self limiting
 Persistent shigella has been described,
often in association with HIV (my
colleague was HIV negative)
Case 3. 26 y.o. ♀ epidemiologist
 Returned
from a year working in Brazil, via
Peru, where she had an acute diarrhoeal
illness, treated with ciprofloxacin with
improvement
 On return, within 1-2 weeks, had recurrent
diarrhoea with small volume, tenesmus,
mucus in stool and lower abdominal pain
Case 3 cont’d
 Stool
C&S negative
 Stool O&P negative
 Stool positive for Clostridium difficile toxin
 Responded to metronidazole (but had one
relapse). Has done well since.
Clostridium difficile
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Infamous as a nosocomial pathogen
Requires “2 hit” sequence, timing may be
important
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Alteration of normal flora by antimicrobial Rx
Exposure to C. difficile, which is common, ubiquitous
in health care settings
Occasionally recognized as a TD pathogen
• CID 2008:46:1060. 6 cases, all had taken abx, no hospital
contact
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Travellers frequently take antibiotics for various
reasons
 Evolving issues
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Increased virulence and changing drug resistance
Relapses common; management unclear
Case 7: 39 y.o ♂. highly travelled
hotel manager
diarrhoea  15 stools/day
over 3-4 weeks after return from Hong
Kong
 20 lb weight loss
 Previous stool C&S & O&P negative
 O/E
 Progressive
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Thin, slightly dehydrated
Oral candidiasis
Lab: cryptosporidia in stool
Case 7 cont’d
 Subsequently
obtained history of
homosexual riskHIV test +
 HIV +, CD4 count 60/
 Required hospitalization, nitazoxanide,
antiretroviral therapy (ART) initiation;
interestingly, he had colonic involvement
 Now doing well on ART, diarrhoea long
since resolved, recently sent a postcard
from Sri Lanka.
Cryptosporidia
 Cryptosporidia
ubiquitous in low income &
industrialized countries, probably a fairly
common cause of travel-related diarrhea
in some settings
 Self limited, albeit after +/- 2 weeks in the
immunocompetent
 Severe persistent disease often seen in
presence of decreased cell mediated
immunity
Misc.
 Amebiasis,
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Entameba histolytica.
Not strictly a tropical disease
Causes persistent colonic involvement
Can cause liver abscess (with or without
diarrhoea or positive stool)
The practical problem is that microscopy
cannot distinguish it from E. dispar, a nonpathogenic commensal which is much more
common than E. histolytica
What if the only positive result is
Blastocystis hominis?
 Controversial
as a pathogen
 ? Strain specificity
 Treatment unclear; options include
metronidazole, cotrimoxazole
What About “Post-Infectious
Irritable Bowel Syndrome”
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Largely a diagnosis of exclusion at present
 Conceivably some of these patients have
infection with as-yet unrecognized organisms
 Several follow up studies show that after specific
infections, e.g. Salmonella, verotoxin producing
E. coli , Campylobacter & Shigella, a high
proportion of people have altered bowel habit
when surveyed many months later, even though
most had not presented to a health care provider
 4-32% of people who have travellers diarrhoea
met the criteria for irritable bowel syndrome
months later
b Study without pathogen identification
Dupont CID 2008;46:594
A Biological Basis?
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Significant increases in the number of rectal
enterochromaffin cells and in lymphocyte counts
have also been reported in patients with
postinfectious IBS, compared with matched
control subjects who recovered from their acute
illness without subsequent IBS
 Alterations of cytokines, serotonin levels & gut
permeability have been reported in PIIBS as
compared to normals
 Is this really a form of irritable bowel syndrome,
or are the mechanisms different?
Risk Factors Associated with Post
Infectious IBS Dupont, CID 2008
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Psychological factors
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Duration of the acute episode
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preexisting psychological disorders have repeatedly been
associated with an increased risk of postinfectious IBS
a history of anxiety or depression has been shown to be less
common among patients with postinfectious IBS than among
those with non-postinfectious IBS (26% vs. 54%).
11-fold increase in the risk of developing postinfectious IBS in
those with acute symptoms lasting >3 weeks compared with
those with an acute illness duration of <1 week
? severity
Etiologic organism? Suggestion of ↑ risk with invasive
pathogens
Antibiotic use associated with development of PI-IBS in
some studies (? Indicator of severity)
Approach to the Patient with
Persistent Diarrhoea Post Travel
 History
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Persistent or recurrent?
Previous bowel habit
Other health problems, *medications
Severity
Blood, mucus
Small vs. large bowel features
Weight loss
Investigation
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Trial of lactose elimination
 Stool for O&P X ?
 Stool C&S
 Stool for C. difficile if any history of
antibiotic exposure
 ??empiric metronidazole +/or ciprofloxacin
 observation
Further investigation?
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If:
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Severity
• Interfering with activity
• +/- patient’s perception
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Weight loss
Blood/mucus in stool
Consider endoscopy + biopsy, starting at the
most likely end, depending on symptoms
 Role for breath test for bacterial overgrowth?
Post Travel IBS: treatment
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Antimotility agents (loperamide, diphenoxylate)
Bulking agents
Other strategies: bismuth, bile salt binders,
probiotics
?? New irritable bowel drugs, e.g. tegaserod
*Reassure the patient regarding our
understanding of the condition, that there are
many other people in the same boat, that
whatever we don’t know about it, we do know
that people with this presentation don’t turn out
later to have some awful exotic disease that
does them in years later
Post travel IBS: ? prevention
 Measures
to prevent acute travellers’
diarrhoea
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Risk reduction
Bismuth
??Dukoral
References
 Dupont.
(review post infectious IBS) CID
2008:46 594
 CATMAT statement. http://www.phacaspc.gc.ca/publicat/ccdr-rmtc/06vol32/acs01/index.html