2. Definition
Measured stool volume greater than 10ml/kg/day,
including changed consistency of stool (loose or
watery) and frequency (≥3 episodes within 24H)
Acute diarrhea: < 2/
52
Persistent diarrhea: 2-3/
52
Chronic diarrhea: > 4/
52
Practical pediatric, 5th edition, Churchill & Livington, 2003
Fre q ue nt p a s s ing o f fo rm e d s to o ls in no t c o ns id e re d a s
d ia rrhe a
Pocket guide on management of acute diarrhea 2011
3. Mechanisms of Diarrhea
6 mechanisms explain pathophysiology of
diarrhea
More than 1 mechanism may present at the
same time
8. Primary
Mechanism
Defect
Secretory
Absorption
Secretion &
electrolytes
transport
Osmotic
Maldigestion,
transport
defect,
ingestion of
unabsorbable
solute
Stool
Examination
Examples
Comment
Watery
Normal
osmolality
Cholera, E.coli,
carcinoid, VIP,
neuroblastoma,
Clostridium
difficile,
cryptosporidiosis
(AIDS)
Persist during
fasting; bile salt
malabsorption may
intestinal water
secretion; no stool
leukocytes
Watery,
acidic, and
reducing
substances;
increased
osmolality
Lactase
deficiency,
glucose-galactose
malabsorption,
lactulose, laxative
abuse
Stops with fasting,
increased breath
hydrogen with
carbohydrate
malabsorption; no
stool leukocytes
9.
10. Primary
Mechanism
Defect
Decreased
motility
Defect in
neuromuscula
r unit (s)
Stool
Examination
Examples
Comment
Loose to normal Pseudoobstructio
appearing stool n
Blind loops
Possible
bacterial
overgrowth
Loose to normal
appearing stool,
stimulated by
gastrocolic
reflex
Infection may
also contribute to
increased motility
Stasis
(bacterial
overgrowth)
Increased
motility
Decreased
transit time
IBS,
thyrotoxicosis,
postvagotomy
dumping
syndrome
11. Primary
Mechanism
Defect
Decreased Decreased
surface area functional
(osmotic, capacity
motility)
Mucosal
invasion
Inflammation,
decreased
colonic
reabsorption,
increased
motility
Stool
Examination
Watery
Examples
Comment
Short bowel
syndrome, celiac
disease, rotavirus
enteritis
May require
elemental diet plus
parenteral
alimentation
Blood and
Salmonella,
Dysentery = blood
increased
Shigella,
+ mucus + WBCs
WBC in stool Yersinia,amebiasi
s Campylobacter,
Nelson textbook of pediatrics, 16th edition
12. Major Causes of Diarrheal
Illnesses
Major Causes of Diarrheal Illnesses:
Secretory Infectious:
Diarrhea 1.Rotavirus
2.Caliciviruses
3.Enteric adenoviruses
4.Astroviruses
Infectious: endotoxin mediated
1.Vibrio cholera
2.Escherichia coli
3.Bacillus cereus
4.Clostridium perfringens
Osmotic
Diarrhea
1.
2.
3.
4.
5.
Neoplastic:
1. Tumor elaboration of peptide,
serotonin or prostaglandins
2. Villous adenoma in distal colon
(nonhormone mediated)
Excess in laxative usage
Disaccharides (lactase) deficiency
Lactulose therapy (for hepatic encephalopathy, constipation)
Perscribed gut lavage for diagnostic procedures
Antacids (MgSO4 and other magnesium salts)
Primary bile acids malabsorption
14. Major Causes of Diarrheal Illnesses:
Deranged
Motility
Decreased intestinal transit time
1. Surgical reduction of gut length
2. Neural dysfunction – IBS
3. Hyperthyroidism
4. Diabetic neuropathy
5. Carcinoid syndrome
Decreased motility (increased intestinal transit time)
1. Small intestine diverticula
2. Surgical creation of ‘blind’ intestinal loops
3. Bacterial overgrowth in small intestine
15. Evaluation of Diarrhea
Acute vs. chronic diarrhea
Acute diarrhea
Complete history/physical examination
Stool examination for occult blood and W
BC
+ no hx to suggest contaminated food viral
Positive bacterial causes must be excluded 1st
Negative
Absence of bacterial pathogens & toxins inflammatory
bowel disease (esp. in adolescent with weight loss, fever &
abdominal pain)
Stool for parasites: not helpful unless diarrhea
persists
19. Specific Causes of Infectious
Diarrhea:
VIRAL CAUSES:
Rotavirus:
Mostly during winter months
Primary infection in infancy – moderate to severe
illness
Reinfection in adolescent – mild illness
MOA:
invade
upper small intestine
May extend throughout small intestine and colon – villous
damage, secondary transient disaccharide deficiency &
inflammation of lamina propria
Vomiting: 3-4days, diarrhea: 7-10days
20.
Vomiting: 3-4days, diarrhea: 7-10days
Treatment: supportive
Addition
of probiotic (lactobacillus GG) or enkephalinase
inhibitor (racecadotril) may shorten duration of illness
Refractory cases- protracted diarrhea may benefit from oral
IgG or lactobacillus GG
22. Organisms
Virulence properties
S
higella
Invasion, enterotoxin, cytotoxin
S onella
alm
Invasion, enterotoxin
Vibrio cholerae
Enterotoxin
Yersinia enterocolitica
Invasion, enterotoxin
Giardia lam
blia
Cyst resistant to physical destruction;
adherence to mucosa
Cryptosporidium
adherence
E
ntam
oeba histolytica
Cyst resistant to physical destruction;
invasion; enzyme and cytotoxin
production
23. Oral Rehydration Therapy:
The cheapest way to treat diarrhea – to
prevent dehydration
Adequate glucose-electrolyte solution
WHO recommendation: ORT + guidance on
appropriate feeding practices main strategy
to achieve reduction in diarrhea related
morbidity and mortality
ORAL REHYDRATION SALT: non proprietary
name for a balanced glucose-electrolyte
mixture
24.
1969: ORS 1st introduced
1969
1984:
1984
Mixture containing trisodium citrate instead of
hydrogen carbonate was introduced
Aim: to produce stability of ORS in hot and humid
climate
Original ORS:
Contain 90mEq/ of sodium total osmolarity
L
of 311mOsm/
L
26. Why reduced osmolarity ORS?
Pharmacokinetics and therapeutics values
Glucose facilitates absorption of sodium (hence
water) on 1:1 molar basis in small intestine
Sodium & potassium are needed to replace body loss
in diarrhea
Citrate corrects acidosis that may occur as results of
diarrhea and dehydration
* * Citrate: systemic alkalizing agent & is used as buffer, sequestrant & emulsion stabilizer,
freely soluble in water
27.
Other clinical benefits:
Reduces stool output or stool volume by ~25% when compared to original WHO-UNICEF ORS
solution
Reduces vomiting by ~30%
Reduces need for unscheduled IV therapy >30%
Less
hospitalization
