Download gastroenteritis

GASTROENTERITIS
BAHAR PEZÜKLİ
NAZLI SEDA GÖKDERELİ

the term gastroenteritis is applied to
syndromes of diarrhea or vomiting that
tend to involve noninflammatory infection
in the upper small bowel or inflammatory
infection in the colon.

Risk of acquiring a gastrointestinal
infection varies greatly with age, living
conditions, personal and cultural habits,
and group exposures
Host defense factors
Gastric acidity
 Intestinal motility
 Intestinal microflora
 Mucus
 Systemic and local immune mechanisms
 Others (e.g. breast feeding)

Bacterial virulence factors
Adherence
 Enterotoxin production
 Cytotoxin production
 Mucosal invasion

Defense Barriers of the Enterocytes
Mechanisms of infection
Ingestion of preformed toxin (food
poisoning)
 Fecal-oral contamination

◦ Food, flies, fingers, feces, and fomites
◦ Contaminated food
 Animal reservoir
 Fecal-oral contamination of food
◦ Infectious dose varies (~100 to 109)
DIARRHEA
Alteration in a normal bowel movement
 Characterized by an increased in the
water content, volume, or frequency of
stools
 >3 or more stools and at least 200 gr


Decrease in consistency (soft or liquid)
and an increase in frequency of bowel
movement to >3 stools per day
Acute diarrhea is an episode of diarrhea
of <14 days in duration
 Persistent diarrhea is of >14 days in
duration
 Chronic diarrhea lasts >30 days

DIARRHEA
Non-inflammatory
 Watery diarrhea, no blood or mucus or
pus in stool, no fever or systemic signs
 Secretory or osmotic mechanism
 Dehydration may occur
 Generally self-limited and more benign
 Therapy generally supportive

Inflammatory
 Frequent lower volume stool, mucoid,
bloody, or purulent. Often with fever or
systemic signs, tenesmus, urgency
 Exudative mechanism
 Dehydration rare
 Less benign

Osmotic Diarrhea
Increased amounts of poorly absorbed,
osmotically active solutes in gut lumen
 Interferes with absorption of water

Secretory Diarrhea
Excess secretion of electrolytes and
water across mucosal surface
 Bacterial or viral enterotoxins
 Cholera, enterotoxigenic E. coli, B. cereus,
S. aureus, Rotavirus, Norwalk virus

Exudative Diarrhea
Intestinal or colonic
mucosa inflamed
and ulcerated
 Leakage of fluid,
blood, pus
 Impairment of
absorption
 Increased secretion
(prostaglandins)

Infectious, invasive organisms
 Shigella, Campylobacter,Yersinia, E.
histolytica, EHEC, C diff
 Idiopathic inflammatory bowel disease
 Crohns disease
 Ulcerative Colitis
 Ischemia

Etiology of Infectious Diarrhea
(in (((8developed countries)
• 70-80%
is viral
• 10-20% is bacterial
– Bacterial are responsible for most severe cases
• < 10% is parasitic
Acute Diarrhea in Children
• The most important infective causes of acute
diarrhea in developing countries in children
are:
• Rotavirus
• Enterotoxigenic escherichia coli
• Shigella
• Campylobacter jejuni
• Salmonella typhimurium
Bacterial
Salmonella
 Shigella
 Shiga-toxin producing Escherichia coli
 Non-shiga-toxin E. coli
 Campylobacter
 Yersinia
 Clostridium difficile
 Vibrio cholerae

Salmonella
Contaminated animal products
 Normal flora in animals

Clinical Symptoms may evolve
 Fever; general malaise
 Sometimes no GI symptoms
 If there are GI symptoms, will see:

Bloody diarrhea
 Abdominal pain
 Weight loss

Salmonellosis



Fever, cramping, abdominal pain, and diarrhea within 848 hours after ingestion of infective dose (contaminated
poultry, shell eggs, dairy products, beef, exotic pets such
as reptiles)
Inflammatory (neutrophilic) enteritis most typically
involving the small bowel mucosa, occasional cause of
colitis with crypt abscesses and erosive ulceration of
colonic mucosa (Salmonella serotype Typhimurium)
Moderate number of fecal neutrophils, usually fewer
than in shigellosis except colitis with blood and pus in
stool
Diagnosis
Stool culture
 Salmonella bacilli may be found in
stool/blood cultures
 Serology: positive Widal test with
increased titers

Treatment
TMP/SMX 960 mg bid or
 Chloramphenicol 250 mg qid for 3 weeks
 In case of sepsis, IV therapy is necessary


Shorter regimens are:
• ciprofloxacin 500 mg bid or ofloxacin
400 mg bid or ceftriaxone 2 g IV for 710 days

Many patients often relapse after treatment and
chronic maintenance therapy (TMP/SMX 1
DD daily) is sometimes necessary.
Shigella
Primarily a human parasite
 Infects the large intestine
 Exotoxin (shiga-toxin)
 Enterotoxin
 May be complicated by reactive arthritis
and rarely HUS
 Very infectious ( ~100 organisms cause
disease)


Clinical Symptoms may evolve
High fever
 Abdominal pain
 Bloody diarrhea

Diagnosis

Stool microscopy— fresh examination
and after concentration

Multiple stool samples may be necessary

Shigella bacillus found in stool
Treatment


TMP/SMX 960 mg bid x 5 days
or
amoxicillin 500 mg tid x 5 days
If resistant to the above, give
or
 norfloxacin 400 mg bid x 5 days
or
 nalidixic acid 1 g qid x 10 days
 ciprofloxacin 500 mg bid

E. coli
Enterohemorrhagic Escherichia coli





Abdominal cramps and watery diarrhea 3 to 8
days following ingestion of contaminated food
(undercooked beef, raw milk, fresh produce) or
water
Shiga toxin absorbed from intestine and damages
vascular endothelial cells (intestinal mucosa and
kidney)
Watery diarrhea followed by grossly bloody
diarrhea
Uncomplicated illness lasts 1 to 12 days
Use of antibiotics contraindicated (phagemediated production of Shiga toxin enhanced by
ampicillin, norfloxacin, and other antibiotics)
Campylobacter
Most common bacterial cause of diarrhea
 Related to Guillain-Barre syndrome (GBS)
– paralysis
 Transmission from infected animals or
food products, fresh or salt water
 Watery diarrhea or dysentery

Clinical Symptoms may evolve
 Fever and general malaise, sometimes
without GI symptoms


When present, GI symptoms include
bloody diarrhea, abdominal pain and
weight loss.
Treatment

Erythromycin 500 mg bid x 5 days (1st
choice)


Fluoroquinolones are also effective, but
resistance rates of 30-50% have been
reported in some developing countries
Yersinia
High degree of abdominal pain
 Mistaken for appendicitis
 Infects the small intestine
 Some can affect the lymphatic system
(intracellular)

Yersinosis
Febrile diarrhea with abdominal pain 16
to 48 hours following ingestion of an
infectious inoculum
 Duration of illness ranges from 1 day to a
prolonged diarrhea of 4 weeks

Treatment
Safe food handling
 Y. enterocolitica is suscestible to
amg,chloram, tetra, TMP/SMZ,pip, cipro,
 ß lactamase, resis to pen, ampi, 1. gen.
ceph.
 Patients with septicemia should receive
antb.
 Y. pseudotuberculosis usually not require
antb, but with septicemia ampi or tetra

Clostridium difficile
Pseudomembranous colitis or antibiotic
associated colitis
 Capable of superinfecting the large
intestine due to drug treatments
 Enterotoxins


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Antibiotics – fluoroquinolones, cephalosporins,
clindamycins, penicillins
Medications:
Proton pump inhibitor
Histamine-2 receptor blockers
Non-steroidal anti-inflammatories (except aspirin)
Laxatives
Narcotics
Antiperistaltic drugs
Advanced age ( ≥ 65yrs.)
Chemotherapy
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Medical/Surgical procedures
Gastrointestinal surgery
Enemas
Enteral tube feedings
Endoscopy
Underlying illness and its severity
Inflammatory bowel disease
Diabetes mellitus/Hyperthyroidism
Leukemia/Lymphoma
Liver/Renal failure
History of C. difficile associated diarrhea
Prolonged hospital stay/Nursing home resident
Treatment
Discontinue the offending agent
 If unable:
 Choose an antibiotic less frequently
associated with antibiotic-associated
diarrhea (aminoglycosides, sulfonamides,
macrolides, vancomycin, tetracyclines)
 Prescribe Metronidazole 500mg PO TID
throughout the needed course of
antibiotic therapy and for 7 days after.

Vibrio cholerae
Heavy lost of fluid “rice-water stool”
 Untreated cases can be fatal

VIRAL GASTROENTERITIS
Background



Acute viral gastroenteritis is a common cause
of morbidity and mortality worldwide.
Conservative estimates put diarrhea in the top
5 causes of deaths worldwide, with most
occurring in young children in nonindustrialized
countries.
In industrialized countries, diarrheal diseases
are a significant cause for morbidity across all
age groups.
Viruses are responsible for a significant
percentage of cases affecting patients of all ages.
 Viral gastroenteritis ranges from a self-limited
watery diarrheal illness (usually < 1 wk)
associated with symptoms of nausea, vomiting,
anorexia, malaise, or fever,
 to severe dehydration resulting in hospitalization
or even death.

The clinician encounters acute viral
gastroenteritis in 3 settings.

The first is sporadic gastroenteritis in infants, which most
frequently is caused by rotavirus.

The second is epidemic gastroenteritis, which occurs either
in semiclosed communities (eg, families, institutions, ships,
vacation spots) or as a result of classic food-borne or
water-borne pathogens.Most of these infections are caused
by caliciviruses.

The third is sporadic acute gastroenteritis of adults, which
most likely is caused by caliciviruses, rotaviruses,
astroviruses, or adenoviruses.
Norovirus
Noroviruses cause approximately 23 million cases
of acute gastroenteritis each year and are the
leading cause of outbreaks of gastroenteritis.
 They are responsible for 68-80% of all outbreaks
in industrialized countries.
 The genus Norovirus, formerly called the
Norwalk-like virus, is a member of the family
Caliciviridae.
 Noroviruses are now recognized to be a
common cause of gastroenteritis in new settings,
including nursing homes and other health care
settings, cruise ships, in other travelers, and in
immunocompromised patients.

The frequency is seasonal.
The highest incidence of rotavirus cases occurs during the months from November to April.
Cruise ship outbreaks of noroviruses are more common during the summer months.
However, a CDC study by Tate et al demonstrated a decline in the seasonality of rotavirus following the 2006
introduction of the rotavirus vaccine.
Rotavirus
Responsible for most morbidity and
mortality from diarrhea
 Babies lacking maternal antibodies are at
risk
 Unique morphological appearance

A feces sample containing Rotavirus, which has a unique
“spoked-wheel” appearance.
Fig. 22.18 Rotavirus visible in a sample of feces from
A child with gastroenteritis.
54
Acute viral gastroenteritis is a
leading cause of infant
mortality throughout the
world.
 By age 3 years, virtually all
children become infected with
the most common agents.
Rotavirus causes 2 million
hospitalizations and 600,000875,000 deaths per year.
 Noroviruses were attributed
to 9 out of the 21 outbreaks
of acute gastroenteritis on
cruise ships reported to the
CDC's Vessel Sanitation
Program from January 1, 2002,
to December 2, 2002.


The occurrence of
noroviruses on cruise ships
has led to the use of the
term "the cruise ship virus"
as another name for these
viruses. Some illnesses
previously attributed to sea
sickness are now
recognized to be caused by
norovirus infections.

Acute viral gastroenteritis occurs
throughout life. Severe cases are seen in
the very young and in the elderly.Etiology
also varies with age.

In infants, most cases are due to rotavirus.

In adults, the most common cause is
norovirus.
Acute diarrhea with vomiting
Food poisoning - toxin
 Staphylococcus aureus
 Bacillus cereus
 Clostridium perfringens

Chronic diarrhea
Enteroaggregative (EAEC) E. coli
 Cyclospora cayetanensis
 Giardia lamblia
 Entamoeba histolytica

MANAGING INFECTIOUS
DIARRHEA
Initial rehidration
Perform thorough clinical and
epidemiological evaluation
 Perform selective fecal studies
 Institute selective therapy for
 Traveler’s diarrhea
 Shigellosis
 Campylobacter infection
 Avoid administering antimotilty agents
 Selectively administer available vaccines


Treatment of specific etiology
 Non-specific treatment
 hydration
 Absorptions (Kaopectate®)
 Bismuth
 Antiperistaltics/opiate derivatives
 Fiber supplementation


Thank you..
sources
https://www.cdc.gov/healthywater/pdf/glo
bal/programs/globaldiarrhea508c.pdf
 http://www.who.int/wer/2008/wer8347.pd
f
 https://www.cdc.gov/disasters/disease/diar
rheaguidelines.html
 https://extranet.who.int/sree/Reports?op=
vs&path=/WHO_HQ_Reports/G36/PRO
D/EXT/FoodborneDiseaseBurden
