Gastroenteritis in Children

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Gastroenteritis in Children

• RR Kalebka

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Definition

• Acute inflammation of the lining of the stomach
  and
• intestines caused by viruses, bacteria or
  their toxins and parasites.
• Presents commonly with diarrhea, abdominal cramps
  and vomiting.
• Common complaint in the ER
• Also significant cause of mortality in
  under-developed countries
• Person to person spread or ingestion of
  contaminated food or water
• Diarrhea daily stools with mass gt 15g/kg for
  children lt2
• 
  gt 200g for children 2

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Common Aetiology

• Viral - Rota virus
  Helminths - Strongyloides
• - Adeno virus
• - Norwalk agent
• - Astro virus
• Bacterial - Enterotoxigenic E.coli
• - Shigella
• - Salmonella
• - Cholera and other
  Vibrios
• - Campylobacter
• - staphylococcus
• Protozoa - Cryptosporidium
• - Giardia
• - E. histolytica

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Food poisoning

• Common foods and pathogens involved with under
  cooked/ inappropriately stored foods.
• Ice cream, custard S. aureus
• Eggs Salmonella
• Dairy Campylobacter/ Salmonella
• Meats C. perfringens/ Salmonella
• Ground beef Enterohemorrhagic E. coli
• Rice - Bacillus cereus

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Water borne

• Viruses
• Shigella
• E. coli
• V. cholera
• E. histolytica
• Poor socio economic conditions
• Lack of sanitation
• Overcrowding

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• Common viral pathogens

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Rota virus

• 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

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Norwalk agent

• Epidemics of diarrhea in communities
• Closed / semi closed communities
• School - age children , family contacts and
  adults affected
• Diarrhea, nausea and abdominal cramps
• Vomiting not prominent
• Self limiting 24 48 hours
• Treatment supportive

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Viral Gastroenteritis

• Summary
• Self limiting
• Usually no bloody stools
• Mild to moderate dehydration
• Generally not toxic
• Usually amenable to oral rehydration and/or
  overnight admission

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• Bacterial gastroenteritis

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Pathogenesis

• Invasion with mucosal ulceration and activation
  of inflammatory cascade, formation of abscesses
• e.g. Campylobacter, Salmonella, Shigella
• Generation of toxins
• e.g Staphylococcal food poisoning
• Shigella toxin
• Combination of above

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Bacterial gastroenteritis

• Bloody diarrhea
• Child appears systemically ill sepsis
• Greater degree of dehydration
• Abdominal pain
• Raised inflammatory markers
• Stool culture will show leucocytes
• gt 5 /hpf
• Extra abdominal organ involvement
• Bacteremia - osteomyelitis
• - meningitis
• - endocarditis

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Common pathogens

• Campylobacter
• Salmonella
• Shigella
• Yersinia
• Pathogenic E.coli
• Cause 10 15 of diarrheal illness
• Under developed nations consider vibrio species

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Salmonella

• Food borne outbreaks in summer
• Incubation 8 48 hrs
• Abdominal cramps / nausea
• May/may not have bloody stools
• White cell count marginally raised
• Stool methylene blue staining shows
  polymorphonuclear lymphocytes
• Rectal swab positive in most cases
• Complications - dehydration
• - dissemination -
  osteomyelitis
• 
  - meningitis
• 
  - endocarditis

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Enteric fever

• Dissemination of certain salmonella
• S.typhi ----- typhoid fever
• Chills and fever, 40deg
• Relative bradycardia
• Splenomegaly
• Macular rash
• Leucopenia

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Shigella

• Swimming pools, water borne, travel
• ASx mild gastroenteritis bacillary dysentry
• Bacillary dysentry
• - profound inflammatory Rx
• - fever , abdominal pain , SICK !
• - diffusely tender abdomen, not
  peritonitic
• - mucoid/bloody stools, tenesmus
• - toxin production causes CNS irritation
• - sheets of neutrophils with methylene
  blue stain
• Complications dehydration, seizures, colonic
  perf.

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E.coli

• Type of illness depends on viro type
• Enterohemorrhagic (EHEC) HUS, haemorrhagic
  colitis
• Enteroaggregative (EAEC ) persistent diarrhea
  in
• 
  underdeveloped countries
• Enteropathogenic (EPEC) leading cause of
  infantile
• 
  diarrhea in africa
• Enteroinvasive (EIEC ) - similar to shigella
  dysentry

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E.Coli O157H7

• Epidemic / sporadic outbreaks
• Contaminated food, partially cooked beef
• Verotoxin producing EHEC
• Affects 3 5yr olds
• Prodromal gastroenteritis followed by
• gt acute renal insufficiency
• gt hemolytic anemia
• gt thrombocytopenia

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Cholera

• Water born
• Unsanitary conditions
• Toxin producing V.cholera
• Heat labile enterotoxin causes inhibition of Na
  reabsorbtion through adenyl cyclase activation
• Incubation 24 72 hours
• Severity of symptoms depends on dose of
  organisms
• Watery brown diarrhea becoming pale ( rice water
  )
• Fluid loss can be MASSIVE

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Approach to Gastroenteritis

• NB MANY sick children present with gastro
• Convenient diagnosis !!
• History
• General examination How sick is the child ?
  Hydration/nutritional state
• System examination exclude co- existing /
  underlying pathology
• Consider differential diagnosis.

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Risk factors for dehydration

• Unable to consume water independently
• Unable to regulate temperature effectively
• Large surface area in relation to weight
• Larger evaporative losses
• - tachypnea
• - crying / tears

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Dehydration

• 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

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Electrolytes 1

• Hypernatremia Na gt 145meq/L
• Causes
• - Water loss gt 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 lt 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

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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

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Parameters of dehydration

• 3-5
  6-9 gt10
• Mental status N
  ill , not toxic lethargic
  
• Heart rate N or up
  tachycardia marked tachy
• Pulse quality N
  N or down poor quality
• Respiratory Rate N
  tachypnoea acidotic
• Capillary refill N lt2s
  2 4s gt 4s
• Perfusion warm
  cool cool, mottled
• Blood pressure N
  N hypotensive
• Eyes N
  slightly sunken very sunken
• Tears N
  decreased absent
• Mucous membranes moist sticky
  dry
• Skin turgor recoil
  delayed markedly delayed
• Urine output N to down down
  minimal

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ORS

• Vomiting not contraindication
• Rehydration modality of choice
• EXCEPT Severe volume
  loss/shock
• - lethargy
• - electrolyte
  problems
• - significant
  co existing/underlying illness
• - acute
  abdomen/ obstruction
• - clinical
  judgment dictates otherwise
• Estimate severity
• Mild 60ml/kg
• Moderate 80ml/kg
• 25 volume given each hour for 4 hours and
  reassess.

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Failure of ORS

• Inability/unwillingness to ingest fluid
• Ongoing losses exceeding rate of replenishment
• Poor technique
• Poor motivation i.e. fed up parent
• Problem of ongoing vomiting ?
• - continue with small volumes frequently
• Nasogastric tube an option continuous
  administration of ORS
• Vomiting not a contraindication
• Safe and efficient alternative

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Resuscitation

• Emergency resuscitation phase
• Re expansion of intravascular space
• Iso tonic crystalloid 0.9NaCl _at_ 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 !!!!

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Replacement phase

• Existing deficit
• dehydration x body weight x 10 ml
• 50 given over first 8 hours, the rest over next
  16hrs

Maintenance fluids Calculation
100ml/kg first 10 kg 50ml/kg next 10kg 25ml/kg
for each kg above 20kg Give fluids as 0.45NaCl
5 dextrose Add 10mmol KCl to each 500 ml NB
. Ongoing losses !!!!! NB ½ darrows contains K
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Electrolytes

• Acidosis
• Assess on blood gas
• Bicarbonate supplement 1/3 x base deficit x
  body weight
• Hyponatremia
• Treat if Na lt 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) /2x 4ml/kg x wt
  (kg)
• Safe rate of change 12mmol/L decline/day

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Role of drugs

• Antibiotics not indicated in viral or
  uncomplicated bacterial Gastroenteritis
• May cause more harm than good
• e.g. prolonging carrier state of some
  Salmonella infections
• potentiation of toxin production
  by pathogenic e.coli
• Antibiotics are indicated in
• gt gastroenteritis complicated by
  septicemia
• gt cholera, shigellosis, enteric fever,
  amoebiasis, giardiasis
• NO antiemetics / anti motility agents
• Oral zinc given in developing countries decreases
  duration of symptoms

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Dont get caught out !!

• gtVomiting only always consider another
  diagnosis
• e.g. poisoning , intestinal obstruction,
  appendicitis, intussusseption and metabolic
  causes
• gtChildren lt3 mo rarely get gastro
• gtUrinary tract infections , URTIs,LRTIs can
  present as gastro