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DR.V.PADMAM.D,FRCP(Glasgow).
PROFESSOR OF MEDICINE SREE BALAJI MEDICAL COLLEGE
Epidemiology of DiarrhoeaLeading cause of illness and death among
children in developing countries.estimated 1.3 thousand million episodes and
4 million deaths occur each year in under-fives.
Main cause of death from acute diarrhoea is dehydration. Other important causes of death are dysentery and undernutrition.
DefinitionsAcute Diarrhoea
sudden onset and lasts less than two weeks 90% are infectious in etiology 10% are caused by medications, toxin ingestions,
and ischemia
Chronic Diarrhoea Diarrhoea which lasts for more than 4 weeks Most of the causes are non-infectious
Persistent Diarrhoea -Diarrhoea lasting between 2 to 4 weeks
Classifications of DiarrhoeaDuration- ( Acute, Chronic)Causes- ( infectious, post-infectious, drugs,
endocrine, factitious)Chronic Dirrhoea- Pathophysiologic mechanism (osmotic, secretory, inflammatory,
abnormal motility)
Mechanism of DiarrhoeaOsmotic DiarrhoeaSecretory DiarrhoeaInflammatory DiarrhoeaAbnormal Motility Diarrhoea
Osmotic DiarrhoeaMechanism : -retention of water in the bowel as a result of an
accumulation of non‐absorbable water‐soluble compounds
-cease with fasting, discontinue oral agentsCauses :
-Purgatives like magnesium sulfate or magnesium containing antacids
-especially associated with excessive intake of sorbitol and mannitol.
-Disaccharide intolerance -Generalized malabsorption
Secretory DiarrhoeaMechanism :
Active intestinal secretion of fluid and electrolytes as well as decreased absorption.
Large volume, painless, persist with fastingCauses :
Cholera enterotoxin, heat labile E.coli enterotoxin
Vasoactive Intestinal Peptide hormone in Verner-Morrison syndrome
Bile salts in colon following ileal resectionLaxatives like docusate sodiumCarcinoid tumours
Inflammatory Diarrhoea
Mechanism : -damage to the intestinal mucosal cell leading to
a loss of fluid and blood -pain, fever, bleeding, inflammatory
manifestations
Causes : -- Immunodeficiency patient
Infective conditions like Shigella dysentryInflammatory conditions
Ulcerative colitis and Crohns disease
Abnormal Motility DiarrhoeaMechanism : -Increased frequency of defecation due to
underlying diseases -large volume, signs of malabsorption
(steatorrhoea)Causes :
Diabetes mellitus- autonomic neuropathyPost vagotomyHyperthyroid diarrhoeaIrritable Bowel Syndrome
EtiologyNon- inflammatory :enterotoxin productionVillus destructionAdherence to surfaceInflammatory:Direct invasioncytotoxins
Mucosal adherence- Bacteria adhere to specific
receptors on the mucosa, e.g. adhesions at the tip of the pili or fimbriae
- Mode of action: effacement of intestinal mucosa causing lesions, produce secretory diarrhoea as a result of adherence
- Causing moderate watery diarrhoea
- e.g. enteropathogenic E.coli
Mucosa Invasion- The bacteria penetrate into the intestinal
mucosa, destroying the epithelial cells and causing dysentery
- e.g. Shigella spp. Enteroinvasive E.coli
Campylobacter spp
Toxin Productioni) Enterotoxins- toxin produced by bacteria adhere to the intestinal
epithelium, induce excessive fluid secretion into the bowel lumen, results in watery diarrhoea without physically damaging the mucosa.
- Some enterotoxin preformed in the food can cause vomiting
- e.g Staph.aureus (enterotoxin B)Bacillus cereusVibrio cholerae
ii) Cytotoxins- damage the intestinal mucosa and sometimes vascular
endothelium, leads to bloody diarrhoea with inflammatory cells, decreased absorptive ability.
- e.g. Salmonella spp. Campylobacter spp.Enterohaemorrhagic E.coli 0157
BacterialCampylobacter jejuniSalmonella sp.ShigellaEscherichia coliStaphylococcal enterocolitisBacillus cereusClostridium perfringensClostridium botulinumGastrointestinal tuberculosis
ViralRotavirusNorovirusAdenovirus
Protozoa
• Entamoeba histolytica• Cryptosporidium
• Giardia intestinalis• Schistosomiasis
1. TravelersTourists to Latin America, Africa, and
Asia develop “traveler's diarrhea” commonly due to enterotoxigenic Escherichia coli, Campylobacter, Shigella, and Salmonella.
Visitors to Russia may have increase risk of Giardia-associated diarrhea.
Visitors to Nepal may acquire Cyclospora.
Campers, backpackers, and swimmers in wilderness areas may become infected with Giardia.
Consumers of Certain FoodDiarrhea closely following food
consumption may suggest infection with Salmonella or Campylobacter from
chicken;Enterohemorrhagic Escherichia coli
(O157:H7) from undercooked hamburger Bacillus aureus from fried riceS. aureus from mayonnaise or creamsSalmonella from eggsVibro species, acute hepatitis A or B from
(raw) seafood
Clinical FeaturesDiarrhoea
WateryBloody
Cramping abdominal painNausea, +/- VomitingFeverLoss of appetiteLethargyShock
Extraintestinal manifestationReactive arthritis :Salmonella ,shigella ,
Yersinia, campylobacter C.difficileGuillain-Barre Syndrome: campylobacterGlomerulonephritis:Shigella ,
campylobacter ,YersiniaIgA nephropathy :campylobacterErythema nodosum: Yersinia ,campylobacter,
salmonellaHemolytic anemia : Yersinia ,campylobacterHUS: shigella , E. coli
Bacterial causes of watery diarrhoea and dysentery
Watery diarrhoeaDysentery- Vibrio cholerae - Shigella spp- Enterotoxigenic E.coli (ETEC) - Yersinia
enterocolitica- Enteropathogenic E.coli (EPEC) - Campylobacter spp- Salmonella spp. - Salmonella spp.- Clostridium difficile - Clostridium difficile- Clostridium perfringens - Enteroinvasive E.coli- Campylobacter jejuni - Enterohaemorrhagic- Bacillus cereus E.coli (EHEC)- Staphylococus aureus
+ profuse vomiting
Diurnal variation No relationship to time of day: Infectious
Diarrhea Morning Diarrhea and after meals
Gastric cause Functional bowel disorder (e.g. irritable
bowel) Inflammatory Bowel Disease
Nocturnal Diarrhea (always organic) Diabetic Neuropathy Inflammatory Bowel Disease
Weight Loss Despite normal appetite
Hyperthyroidism Malabsorption
Associated with fever Inflammatory Bowel Disease
Weight loss prior to Diarrhea onset Pancreatic Cancer Tuberculosis Diabetes Mellitus Hyperthyroidism Malabsorption
Acute Diarrhoea Viral,Bacterial, Protozoa (90%) Medications Laxatives or diuretic
abuse Ingestion of
environmental preformed toxin such as seafood
Ischemic Colitis Graft versus Host
Chronic Diarrhoea Irritable Bowel
Syndrome Diverticular disease Colorectal Cancer Bowel Resection Malabsorption Inflammatory Bowel
Disease Celiac Disease Carcinoid tumour
DIFFERENTIAL DIAGNOSISFood intolerance e.g. Lactose intolerance, Inorganic agents like Sodium nitrite, Organic substances like Mushrooms and
shellfish, Drugs e.g. Laxatives and Antibiotics, Emotional stress.
Diagnostic MethodsStool samples : fresh collectedMucous,bld,white cellsOva & parasites:Recent travel to endemic area,-ve stool cultures,diarrhea > 1wkPart of an outbreak ImmunocompromisedStool cultures:As early as possibleSuspected HUSBloody diarrheaoutbreaks
Diagnostic MethodsStool cultures :Routine : Salmonella,
shigella,yersinia,campylobacter.Toxin assays: C. difficle,E.coliSpecial stains:Aeromonas, cryptosporidium & vibrio
sp.Duodenal aspirate & Biopsy: Giardia,
Isospora,cryptosporidium.ELISAE.M.Colonoscopy & sigmoidoscopy.
DRUG INDUCED DIARRHOEAAntibioticsLaxativesAntihypertensivesLactulose AntineoplasticsAntiretroviral drugsMagnesium
containing compounds
Anti arrhythmicsNSAIDsColchicineAntacidsAcid reducing
agentsProstaglandin
analogs
Antibiotic-induced diarrheaunexplained onset of diarrhea that occurs
with the administration of any antibioticdue to disruption of normal intestinal flora,
which leads toeither proliferation of pathogenic
microorganisms or impairment of the metabolic functions of the microflora
Endocrine causesDiabetic autonomic neuropathyThyrotoxicosisNeuroendocrine tumours ~ Zollinger Ellison syndrome ~ VIPoma ~ Somatostatinoma ~ Carcinoid syndrome ~ Medullary carcinoma of thyroid
Hypokalaemia Depletional hyponatraemia Hypernatraemia Hypophosphataemia Hypomagnesemia Dehydration Hypovolaemic shock
Acute Diarrhoea : ManagementAccess Hydration StatusEncourage fluids intake Consider antibiotics if ill or frail Consider referring if very ill, diabetic on insulin
or metformin Children and Elderly are especially prone to
dehydration. A child should be encouraged by their preferred
diet. Breastfeeding should be continued and alternate
with ORS
Oral Rehydration TherapySodium chloride 3.5 gTrisodium citrate dehydrate 2.9 g(or sodium bicarbonate 2.5g)Potassium chloride 1.5gGlucose 20 gTo be dissolved in one litre of clean drinking water
encourage fluid intake e.g. salt + glucose drink to assist in co-transport of sodium into the epithelial cells via the SGLT1 protein, which enhances water and sodium re-absorption in small intestines.