Transcript ACUTE GASTROENTERITIS IN CHILDREN

ACUTE GASTROENTERITIS IN
CHILDREN
Epidemiology of acute diarrhea:
developed versus developing countries.
Per year
Estimated episodes Hospitalizations
of acute diarrhea
Deaths
United States
375 million — 1.4
episodes per
person per year
> 1.5 million child
outpatient visits
900 000 total
6000 total
200 000 children
300 children
Worldwide
1.5 billion episodes
In developing
countries, children
< 3 y have 3
episodes per year
1.5–2 million
children < 5 y
NON-INFECTIOUS CAUSES
• ERRORS IN FEEDING ( WRONG FORMULA,
WRONG DILUTION)
• FOOD INTOLERANCE
• INFLAMMATION OF THE GUT
• CELIAC DISEASE
• GUT SURGERY
• MUCOVISCIDOSIS
• INFECTIONS OUTSIDE DIGESTIVE
Bacterial gastroenteritis
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± Bloody diarrhea
Child appears systemically ill : sepsis
Greater degree of dehydration
Abdominal pain
Raised inflammatory markers
Stool culture will show leucocytes
> 5 /hpf
Extra abdominal organ involvement :
Bacteremia - osteomyelitis
- meningitis
- endocarditis
Common pathogens
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Campylobacter
Salmonella
Shigella
Yersinia
Pathogenic E.coli
Cause 10 – 15 % of diarrheal illness
Under developed nations consider vibrio species
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Diarrheagenic Escherichia coli. All forms cause disease in
children in the developing world, but enterohemorrhagic E.
coli (EHEC, including E. coli O157:H7) causes disease more
commonly in the developed countries.
• Enterotoxigenic E. coli (ETEC) — traveler’s diarrhea,
diarrhea in infants and children in developing countries.
• Enteropathogenic E. coli (EPEC) — children < 2 years;
chronic diarrhea in children; rarely causes disease in adults.
• Enteroinvasive E. coli (EIEC) — bloody mucoid diarrhea;
fever is common.
• Enterohemorrhagic E. coli (EHEC) — bloody diarrhea; severe
hemorrhagic colitis and the hemolytic uremic syndrome in 6–
8%; cattle are the predominant reservoir.
• Enteroaggregative E. coli (EAggEC) — watery diarrhea in
young children; persistent diarrhea in children and adults with
human immunodeficiency virus (HIV).
E.Coli O157H7
• Epidemic / sporadic outbreaks
• Contaminated food, partially cooked beef
• Verotoxin producing EHEC
• Affects 3 – 5yr olds
• Prodromal gastroenteritis followed by
> acute renal insufficiency
> hemolytic anemia
> thrombocytopenia
• Campylobacter is prevalent in adults and is one of
the most frequently isolated bacteria from the
feces of infants and children in developing
countries.
• • Asymptomatic infection is very common in
developing countries and is associated with the
presence of cattle close to dwellings.
• • Infection is associated with watery diarrhea and
on occasion dysentery (acute bloody diarrhea).
• Peak isolation rates are found in children 2 years of
age and younger.
• • Guillain–Barré syndrome is a rare
complication.
• • Poultry is an important source of
Campylobacter infections in developed
countries.
• • The presence of an animal in the cooking
area is a risk factor in developing countries.
• Shigella species.
• • There are 160 million infections annually in
developing countries, primarily in children.
• • It is more common in toddlers and older children
than in infants.
• • S. sonnei — mildest illness; seen most commonly in
developed countries.
• • S. flexneri — dysenteric symptoms and persistent
illness; most common in developing countries.
• • S. dysenteriae type 1 (Sd1) — produces Shiga toxin,
as does EHEC. It has caused devastating epidemics of
bloody diarrhea with case-fatality rates approaching
10% in Asia, Africa, and Central America.
• Vibrio cholerae.
• • Many species of Vibrio cause diarrhea in
developing countries.
• • V. cholerae serogroups O1 and O139 cause
rapid and severe depletion of volume.
• • In the absence of prompt and adequate
rehydration, hypovolemic shock and death can
occur within 12–18 h after the onset of the first
symptom.
• • Stools are watery, colorless, and flecked with
mucus.
• • Vomiting is common; fever is rare.
• • In children, hypoglycemia can lead to
convulsions and death.
• • There is a potential for epidemic spread; any
infection should be reported promptly to the
public health authorities.
• Salmonella.
• • All serotypes (> 2000) are pathogenic for
humans.
• • Infants and the elderly appear to be at the
greatest risk.
• • Animals are the major reservoir for
Salmonellae.
• • There is an acute onset of nausea, vomiting,
and diarrhea that may be watery or dysenteric.
• • Fever develops in 70% of affected children.
• • Bacteremia occurs in 1–5%, mostly in
infants.
• • Enteric fever — Salmonella typhi or
paratyphi A, B, or C (typhoid fever).
• • Diarrhea (with or without blood) develops,
and fever lasting 3 weeks or more.
• Rotavirus.
• • Leading cause of severe, dehydrating gastroenteritis
among children.
• • One-third of diarrhea hospitalizations and 500 000
deaths worldwide each year.
• • Nearly all children in both industrialized and
developing countries have been infected with rotavirus
by the time they are 3–5 years of age. Neonatal
infections are a common occurrence, but are often
asymptomatic.
• • The incidence of clinical illness peaks in children
between 4 and 23 months of age.
• • Rotavirus is associated with gastroenteritis of aboveaverage severity.
Rotavirus
• Faeco – oral transmission
• 6 – 24 months of age
• Sudden onset watery diarrhea and vomiting with little
abdominal pain
• Self limiting in healthy individuals
• 1 – 6 day duration
Seasonal - temperate climates: “winter gastro”
- tropical climates: summer peak
• Treatment : symptomatic
• Adenovirus.
• • Adenovirus infections most commonly cause
illness of the respiratory system. However,
depending on the infecting serotype and especially
in children, they may also cause gastroenteritis.
• Parasitic agents
• Giardia intestinalis, Cryptosporidium parvum,
Entamoeba histolytica, and Cyclospora cayetanensis
most commonly cause acute diarrheal illness in
children.
• • These agents account for a relatively small
proportion of cases of infectious diarrheal illnesses
among children in developing countries.
Clinical evaluation
• The initial clinical evaluation of the patient
should focus on:
• • Assessing the severity of the illness and the
need for rehydration
• • Identifying likely causes on the basis of the
history and clinical findings
ONSET
Approach to Peds Dehydration
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Initial Resuscitation
Determine % dehydration
Define the type of dehydration
Determine the type and rate of
rehydration fluids
Degree of Dehydration
• Mild dehydration (3-5%)
• Moderate dehydration (6-9%)
• Sever dehydration (10-15%)
The skin pinch is less useful in infants or children with marasmus or kwashiorkor,
or obese children
Parameters of dehydration
3-5%
6-9%
>10%
Mental status
N
ill , not toxic
lethargic
Respiratory Rate
N
tachypnoea
acidotic
Capillary refill
N <2s
2 – 4s
> 4s
Blood pressure
N
N
hypotensive
Urine output
N to down
down
minimal
The best 3 individual examination signs are:
Prolonged Cap refill time
Abnormal Skin turgor
Abnormal resp pattern
Three major classes of dehydration based on
relative losses of Na and Water
1) Isonatremic dehydration (80%)
2) Hypernatremic dehydration (15%)
3) Hyponatremic dehydration (5%)
Dehydration
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Volume depletion - contraction of total IV plasma pool
Dehydration – loss of plasma-free water disproportionate to loss of
sodium
Isonatremic volume depletion :
most common in “dehydrated” children --- VOLUME DEPLETION
Na and H20 lost in proportionate quantities
Excessive extrinsic loss of fluids
Hyponatremic volume depletion
Volume depletion with hyponatremia
Plasma volume contraction with free water excess
e.g child with diarrhea given tap water to replenish losses
Hypernatremic volume depletion
Volume depletion + dehydration
Plasma volume contraction + free water loss
Isonatremic dehydration
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By far the most common
Equal losses of Na and Water
Na = 130-150
No significant change between fluid
compartments
• No need to correct slowly
Hypernatremic Dehydration
• Water loss > sodium loss
• Na >150mmol/L
• Water shifts from ICF ( intracelular fluid) to
ECF
• Child appears relatively less ill
• More intravascular volume
• Less physical signs
• Alternating between lethargy and hyperirritability
Hypernatremic Dehydration
• Physical findings
– Dry doughy skin
– Increased muscle tone
• Correction
– Correct Na slowly
– If lowered to quickly causes
• massive cerebral edema
• intractable seizures
Hyponatremic Dehydration
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Sodium loss > Water loss
Na <130mmol/L
Water shifts from ECF to ICF
Child appears relatively more ill
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Less intravascular volume
More clinical signs
Cerebral edema
Seizure and Coma with Na <120
Hyponatremic Dehydration
• Correction
– Must again be performed slowly unless actively
seizing
– Rapid correction of chronic hyponatremia thought
to contribute to….
Central Pontine Myelinolysis
• Fluctuating LOC
• Pseudobulbar palsy
• Quadraparesis
Electrolytes 1
Hypernatremia : Na > 145meq/L
Causes :
- Water loss > electrolyte loss e.g. diarrhea
- Pure water depletion
-Sodium excess – improper mixing of formula
Plasma tonicity increases ……. Cellular dehydration
Complications – cerebral hemorrhage, seizures,paralysis, encephalopathy
Clinically : abdominal wall skin doughy
Hyponatremia Na < 135meq/L
Causes :
- supplementation of fluid losses with hypotonic fluids
- loss from GI tract
Plasma tonicity decreases …….. Cellular oedema
Complications - cerebral oedema
Clinically : tenting of skin on abdominal wall
Electrolytes 2
• Potassium
Serum potassium may not reflect true potassium
Usually potassium depletion, initially not significant
Consider as part of replacement fluids when adequate urine output
obtained
• Acidosis
Bicarbonate loss in stools
Decreased renal perfusion – less acids excreted
Decreased tissue perfusion – lactic acid production
Laboratory
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CBC
Inflamatory tests
Stool analysis of leucocytes
Stool cultures
Measurement of serum electrolytes is only required in children with
severe dehydration or with moderate dehydration (hypernatremic
dehydration requires specific rehydration methods — irritability and
a doughy feel to the skin are typical manifestations and should be
sought specifically)
• Tests such as BUN and bicarbonate are only helpful when results
are markedly abnormal
• A normal bicarbonate concentration reduces the likelihood of
dehydration
• No lab test should be considered definitive for dehydration
DIFFERENTIAL DG
DIFFERENTIAL DG
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Meningitis
• Bacterial sepsis
• Pneumonia
• Otitis media
• Urinary tract infection
Prevention
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Water, sanitation, and hygiene:
• Safe water
• Sanitation: houseflies can transfer bacterial pathogens
• Hygiene: hand washing
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Safe food:
• Cooking eliminates most pathogens from foods
• Exclusive breastfeeding for infants
• Weaning foods are vehicles of enteric infection
• Micronutrient supplementation: the effectiveness of this depends
on the child’s overall immunologic and nutritional state; further
research is needed.
• Rotavirus: in 1998, a rotavirus vaccine was
licensed in the USA for routine immunization
of infants. In 1999, production was stopped
after the vaccine was causally linked to
intussusception in infants.
• Currently, two vaccines have been approved: a
live oral vaccine (RotaTeq™) made by Merck
for use in children, and GSK’s Rotarix™.
Principles of appropriate treatment for
children with diarrhea and dehydration
WGO Practice Guidelines
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•Oral rehydration solution (ORS) mmol/L
constituents
Sodium
Chloride
Glucose, anhydrous
Potassium
Citrate
Total osmolarity
75
65
75
20
10
245
1. For all children with diarrhea: 20 mg zinc for 14
days.
2. In children who are in hemodynamic shock or with
abdominal ileus, ORT may be contraindicated. For
children who are unable to tolerate ORS via the oral
route (with persistent vomiting), nasogastric feeding
can be used to administer ORS.
Oral rehydration solutions (ORS)
Osmoles
mOsm/L
Glucose
mmol/L
Na
mEq/L
Cl
mEq/L
HCO3
mEq/L
K
mEq/L
WHO
formulation
330
110
90
80
30
20
Pedialyte
270
140
45
35
30
20
AJ
730
690
5
x
x
32
Sports drink
330
255
20
x
3
3
D5W /
0.45% saline
454
300
77
77
0
0
ORT
• Oral rehydration therapy
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Appropriate for mild to moderate dehydration
Safer
Less costly
Administered in various clinical settings
• Fluid replacement should be over
3-4hrs
• 50ml/kg for mild dehydration
• 100ml/kg for moderate dehydration
• 10ml/kg for each episode of vomiting or watery
diarrhea
Minimal or no dehydration.
Mild to moderate dehydration
ORT
• Contraindications to ORT
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Severe dehydration (≥10%)
Ileus or intestinal obstruction
Unable to tolerate (Persistent vomiting)
Signs of shock
Decreased LOC (Level of consciousness) or unconscious
Unclear diagnosis
Psychosocial situations
Severe dehydration.
Resuscitation
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Emergency resuscitation phase
Re – expansion of intravascular space
Iso tonic crystalloid – 0.9%NaCl = 20ml/kg over 20 minutes
Ringers
Plasmalyte
Reassess after each bolus
Repeat up to 60ml/kg
No improvement ? Reassess for other pathology e.g septic shock
NB NB check glucose !!!!
Replacement phase
Existing deficit
%dehydration x body weight x 10 = ml
50% given over first 8 hours, the rest over next 16hrs
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Maintenance fluids
Calculation :
100ml/kg first 10 kg
50ml/kg next 10kg
25ml/kg for each kg above 20kg
Give fluids as 0.45%NaCl + 5% dextrose
Add 10mmol KCl to each 500 ml
NB . Ongoing losses !!!!!
NB ½ darrows contains K
Electrolytes
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Acidosis
Assess on blood gas
Bicarbonate supplement : 1/3 x base deficit x body weight
Hyponatremia
Treat if Na < 125
Calculate Na deficit = (Desired Na – Measured Na) x 0.6 x kg
Safe rate of change = 12mmol/L rise / day
• Hypernatremia
pure free water deficit
Calculate [(Na – 145) /2]x [4ml/kg] x wt (kg)
Safe rate of change = 12mmol/L decline/day
Severe Dehydration
• Management of severe dehydration requires IV
fluids
• Fluid selection and rate should be dictated by
• The type of dehydration
• The serum Na
• Clinical findings
• Aggressive IV NS bolus remains the mainstay of
early intervention in all subtypes
Isonatremic Dehydration
• Calculate the fluid deficit
• Deficit (cc’s) = % dehydration x body wt
• D5½NS is fluid of choice
• (½ deficit – the bolus) over the first 8hrs
• Add maintenance and any ongoing losses to above
• Further ½ the deficit replaced over the next 16hrs
• Monitor electrolytes and U/O
Hypernatremic Dehydration
• Fluid deficit =
(Current Na/Desired Na – 1) x 0.6 x body wt
• Replace with D50.2%NS
• Replace over 48hrs
• Reduce sodium by no more than 10mEq/L/24hrs
• (½ deficit – the bolus) over the first 24hrs
– Add maintenance and any ongoing losses to above
– Further ½ the deficit replaced over the next 24hrs
Hyponatremic dehydration
• Na deficit =
(Nadesired- Nacurrent) x 0.6 x Weight (kg)
• Divide above by Na in mEq/L within the
replacement fluid
• 154 mEq in NS
• 77 mEq in D5½ NS
• 513 in 3% saline
• divide by deficit x 2 to determine rate at
0.5mEq/L/hr
Hyponatremic Dehydration
• If seizing
• Correct with 3% Saline bolus
• Target a Na of 120
• Further correction beyond this with D5½ NS
• If not Seizing
• Correct with D5½ NS
• Target a Na of 130
• Watch for Central Pontine Myelinolysis
• More likely in chronic hypo-Na with less Sx
• Correct slowly at rate of 0.5mEq/L/hr
• Alternative antimicrobials for treating cholera
in children are TMP-SMX (5 mg/kg TMP + 25
mg/kg SMX, b.i.d. for 3 days), furazolidone
(1.25 mg/kg, q.i.d. for 3 days), and norfloxacin.
CAMPYLOBACTER
• Erythromycin is hardly used for diarrhea today.
Azithromycin is widely available and has the convenience of
single dosing. For treating most types of common bacterial
infection, the recommended azithromycin dosage is 250 mg
or 500 mg once daily for 3–5 days. Azithromycin dosage for
children can range (depending on body weight) from 5 mg
to 20 mg per kilogram of body weight per day, once daily
for 3–5 days.
• • Quinolone-resistant Campylobacter is present in several
areas of South-East Asia (e.g., in Thailand) and
azithromycin is then the appropriate treatment
PROBIOTICS
• Several probiotics (Saccharomyces boulardii ,
Lactobacillus rhamnosus and a mixture of Lactobacillus
acidophilus and Bifidobacterium bifidum) had
significant efficacy (at preventing traveler’s diarrhea)”
• Probiotics mixture reduced the severity of diarrhea and
length of hospital stay in children with acute diarrhea.
In addition to restoring beneficial intestinal flora,
probiotics may enhance host protective immunity such
as down-regulation of pro-inflammatory cytokines and
up-regulation of anti-inflammatory cytokines
Antimotility Drugs
• loperamide is the agent of choice for adults (4–6
mg/day; 2–4 mg /day for children > 8 y). —
• for mild to moderate traveler’s diarrhea (without
clinical signs of invasive diarrhea).
• inhibits intestinal peristalsis and has mild antisecretory
properties.
• should be avoided in bloody or suspected
inflammatory diarrhea (febrile patients). — Significant
abdominal pain also suggests inflammatory diarrhea
(this is a contraindication for loperamide use). —
• loperamide is not recommended for use in children < 2
y.
Antisecretory agents
• • Bismuth subsalicylate can alleviate stool output in
children or symptoms of diarrhea, nausea, and
abdominal pain in traveler’s diarrhea.
• • Racecadotril ( acetetorphan) is an enkephalinase
inhibitor (nonopiate) with antisecretory activity, and is
now licensed in many countries in the world for use in
children. It has been found useful in children with
diarrhea, but not in adults with cholera.
• Adsorbents:
• • Kaolin-pectin, activated charcoal, attapulgite —
Inadequate proof of efficacy in acute adult diarrhea
Anti- emetics
A single dose of oral Ondansetron (a
serotonin antagonist anti-emetic) in children
with G/E and dehydration reduces vomiting,
facilitate oral rehydration and suitable for the
use in emergency department