U1 L4 GASTROENTERITIS, U1 L4 GASTROENTERITIS.pdf

U1 L4 GASTROENTERITIS.pdf
U1 L4 GASTROENTERITIS.pdf

1. GASTROENTERITIS
(u1l4)

Mohammad Javed Ansari, PhD.
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2. OBJECTIVES OF THE LECTURE
•At the end of this lecture, you will be able to learn:
•What is gastroenteritis?
•Epidemiology-Incidence, prevalence, morbidity,
mortality, Risk factors.
•Etiology
•Pathophysiology
•Signs and symptoms, complications
•Clinical evaluations,
•Management, Pharmacotherapeutics
•Prophylaxis








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3. GASTROENTERITIS
•Gastroenteritis is an inflammation of the
gastrointestinal tract involving-
•Stomach, or
•Intestines, or
•Both.
•Gastroenteritis is frequently termed "stomach flu" or
"gastric flu" because the most frequent cause of
gastroenteritis is viral.
•Influenza viruses (flu viruses) do not cause
gastroenteritis.
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4. GASTROENTERITIS- ETIOLOGY
•Etiology:
•Viral 50-70%
•Rotavirus, Noraviruses,
•Caliciviruses, Adenovirus, Parvovirus, Astrovirus
•Bacterial 15-20%
•Salmonella, Shigella, and Campylobacter species are the
top 3 leading causes of bacterial diarrhea worldwide,
followed closely by Aeromonas species
•Parasitic 10-15%
•Entamoeba hystolytica, Giardia intestinalis
•Others:
•Toxins, drugs etc.
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5. GASTROENTERITIS - PATHOPHYSIOLOGY
•Infectious agents reach to GI tract via unhygienic
food, water, or contacts etc.
•They cause diarrhea by adherence, mucosal
invasion, enterotoxin production, and/or cytotoxin
production.
•These result in increased fluid secretion and/or
decreased absorption.
•The increased luminal fluid content that cannot be
adequately reabsorbed, leading to dehydration and
the loss of electrolytes and nutrients.





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6. GASTROENTERITIS - PATHOPHYSIOLOGY
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Viral gastroenteritis Bacterial gastroenteritis
50-70% cases 15-20% cases
Rotavirus in most cases
Sporadic, severe diarrhoea,
Mostly in children under 5 years
Incubation period is 2-4 days
Symptoms lasting 3-5 days
Vaccine available
Staphylococcus aureus
contaminates (food poisoning),
produces endotoxins.
Salmonella spp., Shigella
spp., and Clostridioides spp.
follow staph.
Norovirus / Norwalk
Mostly found in adults
Incubation period of 16-48 hrs
Duration of 1-2 days
Toxins cause acute nausea,
vomiting, and diarrhoea within
12 h of ingestion of
contaminated food.
Symptoms abate within 36 h.

7. GASTROENTERITIS - PATHOPHYSIOLOGY
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Viral gastroenteritis Bacterial gastroenteritis
50-70% cases 15-20% cases
Adenoviruses
year-round, or in summer
Children under 2 years
Incubation period is 3-10
days
Vibrio cholerae, EnteroToxigenic
strains of E. coli (ETEC) adhere to
intestinal mucosa without invading and
produce enterotoxins.
Clostridium difficile produces a
similar toxin when overgrowth follows
antibiotic use.
Toxins impair intestinal absorption and
cause secretion of electrolytes and
water by stimulating adenylate cyclase,
resulting in watery diarrhoea.
Astrovirus
infects infants and
children.
Common in winter.
Incubation is 3 to 4 days.

8. GASTROENTERITIS - PATHOPHYSIOLOGY
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Viral gastroenteritis Bacterial gastroenteritis
50-70% cases 15-20% cases
In US, noroviruses cause
21% of all acute
gastroenteritis cases in
young children with
outpatient visits,
emergency department
visits, and annual
hospitalizations
numbering, 627,000,
281,000, and 14,000,
respectively
-Shigella, Salmonella,
Campylobacter, Enterohemorrhagic
E. coli-EHEC) invade the mucosa of
intestine and cause microscopic
ulceration, bleeding, exudation of
protein-rich fluid, and secretion of
electrolytes and water.
-It produces Shiga toxin, which causes
bloody diarrhoea (hemorrhagic
colitis).
-Hemolytic-uremic syndrome is a
serious complication.

9. GASTROENTERITIS - PATHOPHYSIOLOGY
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Viral gastroenteritis Bacterial gastroenteritis
-Induce maldigestion of
carbohydrates,
-Malabsorption of
nutrients
-Inhibition of water
reabsorption, can lead to
a malabsorption
component of diarrhoea.
-Mucosal adherence- affects water
reabsorption
--Enterotoxin production-induce
excessive fluid secretion.
-Both causes watery diarrhoea
-Mucosal invasion- ‘invasins’ disrupt
the host cell facilitating invasion.
-- Cytotoxin production- damage the
intestinal mucosa and, in some cases,
vascular endothelium as well.
Both causes dysentery (low-volume
bloody diarrhoea, with abdominal pain).
Rotavirus secretes an
enterotoxin, NSP4, which
leads to a Ca2+ -
dependent Cl- secretory
mechanism.

10. GASTROENTERITIS - PATHOPHYSIOLOGY
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Protozoan Parasites Drug induced diarrhoea
Giardia lintestinalis
adhere to or invade the
intestinal mucosa.
(Giardiasis).
-Infection can become
chronic and cause a
malabsorption syndrome.
Laxatives like docusate sodium induces
Secretory diarrhoea, by activating
intestinal secretion of fluids and
electrolytes as well as decreased
absorption.
Large volume, painless, persists with
fasting.
-Purgatives like Magnesium sulfate or
magnesium containing antacids causes
Osmotic diarrhoea, retention of
water in the large intestine as a result
of an accumulation of non-absorbable,
water soluble compounds.

Entamoeba histolytica
cause of subacute bloody
diarrhoea (amoebiasis).
-Cryptosporidiosis,
Cyclospora, Microsporidia
etc.

11. GASTROENTERITIS - PATHOPHYSIOLOGY
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Viruses Bacterial/ Drug / disease induced diarrhoea
Secretory
diarrhoea, active
intestinal secretion of
fluids and
electrolytes as well
as decreased
absorption. Large
volume, painless,
persists with fasting.
Causes-Cholera,
enterotoxin,
thermolabile, E. coli
enterotoxin,
Laxatives like
docusate sodium
Inflammatory (or mucosal) diarrhoea, damage
to intestinal mucosal cell leading to a loss of
fluids and blood. Causes- Immunodeficiency,
Shigella dysentery
Inflammatory conditions like Ulcerative colitis.
Motility diarrhoea, increases frequency of
defecation due to underlying diseases.
Large volume, signs of Malabsorption.
Causes- DM – autonomic neuropathy
Hyperthyroid diarrhoea, IBS.
Osmotic diarrhoea: Especially associated with
excessive intake of Sorbitol and Mannitol.,
Generalized malabsorption.
Secretory diarrhoea: Toxins, Drugs, etc.

12. GASTROENTERITIS – SIGN & SYMPTOMS
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Viral gastroenteritis Bacterial gastroenteritis
◦Nausea and vomiting
◦Watery diarrhoea
◦Fever
◦Headaches
◦Abdominal cramps
◦Nausea and vomiting
◦Bloody Diarrhoea
◦Anorexia, Fever
◦Headaches
◦Abnormal flatulence
◦Abdominal pain
◦Abdominal cramps
◦Fainting and Weakness
◦Heartburn
Usually acute onset,
lasting 1–3 days, and is
self- limiting.

Usually acute onset,
lasting 3–7 days.
Antibiotics required.

13. GASTROENTERITIS –CLINICAL EVALUATIONS
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14. GASTROENTERITIS –CLINICAL EVALUATIONS
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15. GASTROENTERITIS –CLINICAL EVALUATIONS
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Viral gastroenteritis Bacterial gastroenteritis
Diagnosed using
commercially
available rapid
assays that detect
viral antigen in the
stool, but these are
usually done only to
document an
outbreak.

-If watery diarrhoea persists > 48 h,
stool examination (fecal WBCs, ova,
parasites) and culture are indicated.
-Patients with bloody diarrhoea should
usually have sigmoidoscopy with
cultures and biopsy.
-Diagnosis of giardiasis or
cryptosporidiosis, stool antigen detection
using an enzyme immunoassay has a
higher sensitivity.
-Patients with recent antibiotic use
should have a stool assay for C. difficile
toxin.

16. GASTROENTERITIS –MANAGEMENT
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Viral gastroenteritis Bacterial gastroenteritis
The treatment of dehydrating
diarrheal diseases was
revolutionized by oral
rehydration solutions.

Patients who are severely
dehydrated or in whom
vomiting precludes the use of
oral therapy should receive IV
solutions such as Ringer's
lactate.
-Symptomatic treatments
- Oral rehydration solutions.

-Antimicrobial agents can
shorten the duration of illness
from 3–4 days to 24–36 h.

-Loperamide should not be
used by patients with fever or
dysentery; its use may prolong
diarrhoea in patients with
infection due to Shigella or
other invasive organisms.

17. GASTROENTERITIS –MANAGEMENT- ORT- IVRT
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•Fluid replacement is the cornerstone of therapy for diarrhea
regardless of etiology.
•Initial assessment of fluid loss is essential for rehydration.
•Weight loss is the most reliable means of determining the
extent of water loss.
•Weight loss of 9% to 10% is considered severe and requires IV
fluid replacement with Ringer’s lactate or 0.9% sodium
chloride.
•IV therapy is also indicated in patients with uncontrolled
vomiting, the presence of paralytic ileus, stool output greater
than 10 mL/kg/hour, shock, or loss of consciousness.
•The maintenance phase should not exceed 100 to 150
mL/kg/day and is generally adjusted to equal stool losses.

18. GASTROENTERITIS –MANAGEMENT- ORT-IVRT
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19. GASTROENTERITIS –MANAGEMENT
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Adults Children
•Ciprofloxacin, 750 mg as a single
dose or 500 mg bid for 3 days.
•Levofloxacin, 500 mg as a single
dose or 500 mg qd for 3 days;
•Norfloxacin, 800 mg as a single
dose or 400 mg bid for 3 days.
•Azithromycin, 1000 mg as a single
dose or 500 mg qd for 3 days.
•Rifaximin, 200 mg tid or 400 mg
bid for 3 days (not recommended
for use in dysentery).
Azithromycin
10 mg/kg on day 1,
5 mg/kg on
days 2 and 3 if
diarrhoea persists.

Alternative
Furazolidone,
7.5 mg/kg per day in
four divided doses for 5
days..
Vaccines as
a prophylaxis should be
taken.

20. Questions..




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