1-diarrhoea.ppt

7/27/2019 1-diarrhoea.ppt

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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


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Acute Infective Diarrhoea

Epidemiology and predisposition

Aetiology

Virus (commonest: Rotavirus)

Bacteria - Invasive

EnterotoxigenicParasites

Fungi


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Pathogenesis of Diarrhoea

Depends on pathogen

VIRUS DIARRHOEA (eg Rotavirus)

Effect on villus structure and functionEnzyme damage

Significant effect on digestion and

absorptionSecretion-absorption imbalance


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Pathogenesis of Bacterial Diarrhoea

without mucosal injury

mediated by:

EnterotoxinsAdhesins

with mucosal injury

mediated by:

Adhesins

Invasins

Cytotoxins


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Paediatric DiarrhoeaEmerging issues

Food borne organisms of increasing importance with contamination of

stored/transported food

Campylobacter Poultry, meat

Salmonella Poultry, Dairy ProduceYersinia Meat

Bacillus cereus Reheated cereals

Vibrio parahaemolyticus Fish products

Unhygienic handling of food

Esch coli 0157 mince meat

Staph aureus


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Mechanisms of acute diarrhoea

Osmoticeg Lactose intolerance

Secretory

eg Cholera Mixed secretory-osmotic

eg Rotavirus

Mucosal inflammationeg Invasive bacteria

Motility disturbance


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Effects of Diarrhoea

Dehydration

Biochemical disturbances

Sodium, Potassium

Metabolic acidosisBlood glucose

Uraemia

Convulsions Severe gut damage : ileus, NEC, PLE


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Clinical patterns

Some associated features depend on

pathogen:

Rotavirus

Invasive bacteria

Toxigenic bacteria

Fever, abdominal pain, early or late

vomiting, other symptoms


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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


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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 ofacute insult - different management)


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Chronic diarrhoea

With failure to thrive and excessive stoolwater losses

Small intestinal mucosal injury

With failure to thrive but without excessivestool water losses

Malabsorption syndromes

Without failure to thriveMotility disorder


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Small intestinal mucosal injury

Initiating acute insult - infection

Contributing malnutrition, young age, feedingproblem

Acute diarrhoea does not stop

Leads to malnutrition Aggravation by unmodified food

Immunological consequences

Contributes big percentage of deaths fromdiarrhoeal disease


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Diarrhoea in symptomatic HIV infection

Chronic diarrhoea: AIDS-defining condition

Severe mucosal damage with multipledefects of digestion and absorption

Associated infections

Intestinal super-infection withcryptosporidium, salmonella, opportunists

Protein-losing enteropathy can maskhyperglobulinaemia


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Lactose intolerance

Development of symptoms following lactoseexposure 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

timeNeeds feed change only with failure to thrive


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Lactose intolerance

Congenital deficiency very rareWatery, acid diarrhoea from birth

Genetic primary adult lactase deficiency verycommon in Africa

Acquired deficiency common in severegastroenteritis, malnutrition

Usually self-limiting without treatment

Feed change with persistent high stool wateroutput


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Fat malabsorption

Diagnosis : stool microscopy, quantitative Pancreatic deficiency (eg cystic fibrosis)

Increased appetite cf intestinal disease

Greasy floating stools, foul-smellingTreated with enzyme replacement

Bile salt deficiency (chronic liver disease)

Bile salt deconjugationBacterial overgrowth in gut disease

Treated with bowel cocktail


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Food allergy

Not equivalent to food intolerance

Requires exposure and sensitization beforesymptoms 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


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Food intolerance

Symptoms after ingestion of food, the word does notindicate the pathology. Can be:

Allergic or immunological

Allergic enteropathy

Biochemical - enzyme deficiencies

Lactose intolerance

ChemicalLaxative, salicylate


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Coeliac disease

Gluten-induced enteropathy : gliadin fraction ofwheat 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


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Motility disorders

Irritable bowel syndrome, Toddler diarrhoea

Between 6 months and 4 years

Normal growth and weight gain

Intermittent episodes, not at night

Stools get progressively more loose through theday, may contain undigested vegetables

Family history of spastic colon

Reassurance most important

1-diarrhoea.ppt

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