Download Acute Diarrhoea

Acute Diarrhoea
• Definition
Increased frequency and water content of stools
than is normal for the individual
Usually: > 3 stools per day
• Descriptive
Watery, mucoid, dysenteric
• Pathogenetic:
Infective, non-infective
Acute Infective Diarrhoea
• Epidemiology and predisposition
• Aetiology
Virus (commonest: Rotavirus)
Bacteria - Invasive
Enterotoxigenic
Parasites
Fungi
Pathogenesis of Diarrhoea
Depends on pathogen
• VIRUS DIARRHOEA (eg Rotavirus)
Effect on villus structure and function
Enzyme damage
Significant effect on digestion and
absorption
Secretion-absorption imbalance
Pathogenesis of Bacterial Diarrhoea
• without mucosal injury
mediated by:
Enterotoxins
Adhesins
• with mucosal injury
mediated by:
Adhesins
Invasins
Cytotoxins
Paediatric Diarrhoea
Emerging issues
Food borne organisms of increasing importance with contamination of
stored/transported food
Campylobacter
Salmonella
Yersinia
Bacillus cereus
Vibrio parahaemolyticus
Poultry, meat
Poultry, Dairy Produce
Meat
Reheated cereals
Fish products
Unhygienic handling of food
Esch coli 0157
Staph aureus
mince meat
Mechanisms of acute diarrhoea
• Osmotic
eg Lactose intolerance
• Secretory
eg Cholera
• Mixed secretory-osmotic
eg Rotavirus
• Mucosal inflammation
eg Invasive bacteria
• Motility disturbance
Effects of Diarrhoea
• Dehydration
• Biochemical disturbances
Sodium, Potassium
Metabolic acidosis
Blood glucose
Uraemia
• Convulsions
• Severe gut damage : ileus, NEC, PLE
Clinical patterns
• Some associated features depend on
pathogen:
Rotavirus
Invasive bacteria
Toxigenic bacteria
• Fever, abdominal pain, early or late
vomiting, other symptoms
Management of diarrhoea
• Replace the fluids and electrolytes which are lost
• Drug therapy has very little place
Antibiotic
Antisecretory
Antimotility
• Nutritional management
• Follow-up to ensure recovery
Chronic diarrhoea
Diarrhoea can be categorized as:
• Acute: less than 7 - 10 days
• Persistent: More than 7 - 10 days
• Chronic: More than 14 - 21 days
(Persistent diarrhoea often a prolonged course of
acute insult - different management)
Chronic diarrhoea
• With failure to thrive and excessive stool
water losses
Small intestinal mucosal injury
• With failure to thrive but without excessive
stool water losses
Malabsorption syndromes
• Without failure to thrive
Motility disorder
Small intestinal mucosal injury
• Initiating acute insult - infection
• Contributing malnutrition, young age, feeding
problem
• Acute diarrhoea does not stop
• Leads to malnutrition
• Aggravation by unmodified food
• Immunological consequences
• Contributes big percentage of deaths from
diarrhoeal disease
Diarrhoea in symptomatic HIV infection
• Chronic diarrhoea: AIDS-defining condition
• Severe mucosal damage with multiple
defects of digestion and absorption
• Associated infections
• Intestinal super-infection with
cryptosporidium, salmonella, opportunists
• Protein-losing enteropathy can mask
hyperglobulinaemia
Lactose intolerance
• Development of symptoms following lactose
exposure due to lactase deficiency
• Luminal fermentation of undigested lactose
• Acid diarrhoea with lactose in stools
• Diagnosed:
History, low stool pH, positive reducing sugars
• Relative lactase deficiency at birth improves with
time
Needs feed change only with failure to thrive
Lactose intolerance
• Congenital deficiency very rare
Watery, acid diarrhoea from birth
• Genetic primary adult lactase deficiency very
common in Africa
• Acquired deficiency common in severe
gastroenteritis, malnutrition
• Usually self-limiting without treatment
• Feed change with persistent high stool water
output
Fat malabsorption
• Diagnosis : stool microscopy, quantitative
• Pancreatic deficiency (eg cystic fibrosis)
Increased appetite cf intestinal disease
Greasy floating stools, foul-smelling
Treated with enzyme replacement
• Bile salt deficiency (chronic liver disease)
• Bile salt deconjugation
Bacterial overgrowth in gut disease
Treated with “bowel cocktail”
Food allergy
• Not equivalent to food intolerance
• Requires exposure and sensitization before
symptoms develop
GIT and/or skin, nose, resp. symptoms
• Not common 1 - 4% of children, most < 2yr
• Careful diagnosis
Atopic family history, allergy tests,
food elimination and challenge
• Beware nutritional adequacy of elimination diets
Food intolerance
Symptoms after ingestion of food, the word does not
indicate the pathology. Can be:
• Allergic or immunological
Allergic enteropathy
• Biochemical - enzyme deficiencies
Lactose intolerance
• Chemical
Laxative, salicylate
Coeliac disease
• Gluten-induced enteropathy : gliadin fraction of
wheat protein
• Symptoms after exposure to wheat
• Genetic factors : HLA-B8
• Auto-immune disorder
• Villous atrophy with malabsorption
• Resultant malnutrition
• Anti-Endomysium, -gliadin IgA, jejunal biopsies
• Total wheat product exclusion lifelong
Motility disorders
Irritable bowel syndrome, Toddler diarrhoea
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Between 6 months and 4 years
Normal growth and weight gain
Intermittent episodes, not at night
Stools get progressively more loose through the
day, may contain undigested vegetables
• Family history of “spastic colon”
• Reassurance most important