This document discusses the epidemiology, mechanisms, causes, clinical features and management of diarrhoea. It notes that diarrhoea is a leading cause of illness and death in children in developing countries, with an estimated 1.3 billion episodes and 4 million deaths annually in under-fives. The main causes of acute diarrhoea are viral, bacterial and protozoal infections (90% of cases), while chronic diarrhoea has non-infectious causes like irritable bowel syndrome. Dehydration is the main cause of death from acute diarrhoea.

1. DR.V.PADMA
M.D,FRCP(Glasgow).
PROFESSOR OF MEDICINE
SREE BALAJI MEDICAL COLLEGE

2. Epidemiology of Diarrhoea
Leading 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.

3. Definitions
Acute 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

4. Classifications of Diarrhoea
Duration-
( Acute, Chronic)
Causes-
( infectious, post-infectious, drugs, endocrine,
factitious)
Chronic Dirrhoea-
Pathophysiologic mechanism
(osmotic, secretory, inflammatory, abnormal
motility)

5. Mechanism of Diarrhoea
Osmotic Diarrhoea
Secretory Diarrhoea
Inflammatory Diarrhoea
Abnormal Motility Diarrhoea

6. Osmotic Diarrhoea
Mechanism :
-retention of water in the bowel as a result of an
accumulation of non-absorbable water-soluble
compounds
-cease with fasting, discontinue oral agents
Causes :
-Purgatives like magnesium sulfate or magnesium
containing antacids
-especially associated with excessive intake of sorbitol
and mannitol.
-Disaccharide intolerance
-Generalized malabsorption

7. Secretory Diarrhoea
Mechanism :
Active intestinal secretion of fluid and electrolytes as
well as decreased absorption.
Large volume, painless, persist with fasting
Causes :
Cholera enterotoxin, heat labile E.coli enterotoxin
Vasoactive Intestinal Peptide hormone in Verner-
Morrison syndrome
Bile salts in colon following ileal resection
Laxatives like docusate sodium
Carcinoid tumours

8. 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 dysentry
Inflammatory conditions
 Ulcerative colitis and Crohns disease

9. Abnormal Motility Diarrhoea
Mechanism :
-Increased frequency of defecation due to underlying
diseases
-large volume, signs of malabsorption (steatorrhoea)
Causes :
Diabetes mellitus- autonomic neuropathy
Post vagotomy
Hyperthyroid diarrhoea
Irritable Bowel Syndrome

10. Etiology
Non- inflammatory :
enterotoxin production
Villus destruction
Adherence to surface
Inflammatory:
Direct invasion
cytotoxins

13. 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

14. 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

15. Toxin Production
i) 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 cereus
Vibrio 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

16. Bacterial
Campylobacter jejuni
Salmonella sp.
Shigella
Escherichia coli
Staphylococcal enterocolitis
Bacillus cereus
Clostridium perfringens
Clostridium botulinum
Gastrointestinal tuberculosis

17. Viral
Rotavirus
Norovirus
Adenovirus
Protozoa
• Entamoeba histolytica
• Cryptosporidium
• Giardia intestinalis
• Schistosomiasis

19. 1. Travelers
Tourists 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.

24. Consumers of Certain Food
Diarrhea 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 rice
S. aureus from mayonnaise or creams
Salmonella from eggs
Vibro species, acute hepatitis A or B from (raw)
seafood

25. Clinical Features
Diarrhoea
Watery
Bloody
Cramping abdominal pain
Nausea, +/- Vomiting
Fever
Loss of appetite
Lethargy
Shock

26. Extraintestinal manifestation
Reactive arthritis :Salmonella ,shigella , Yersinia,
campylobacter C.difficile
Guillain-Barre Syndrome: campylobacter
Glomerulonephritis:Shigella , campylobacter
,Yersinia
IgA nephropathy :campylobacter
Erythema nodosum: Yersinia ,campylobacter,
salmonella
Hemolytic anemia : Yersinia ,campylobacter
HUS: shigella , E. coli

28. Bacterial causes of
watery diarrhoea and dysentery
Watery diarrhoea Dysentery
- 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

29. 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

30. 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

31. 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

33. DIFFERENTIAL DIAGNOSIS
Food intolerance e.g. Lactose intolerance,
Inorganic agents like Sodium nitrite,
Organic substances like Mushrooms and shellfish,
Drugs e.g. Laxatives and Antibiotics,
Emotional stress.

36. Diagnostic Methods
Stool samples :
 fresh collected
Mucous,bld,white cells
Ova & parasites:
Recent travel to endemic area,-ve stool cultures,diarrhea > 1wk
Part of an outbreak
Immunocompromised
Stool cultures:
As early as possible
Suspected HUS
Bloody diarrhea
outbreaks

37. Diagnostic Methods
Stool cultures :
Routine : Salmonella, shigella,yersinia,campylobacter.
Toxin assays: C. difficle,E.coli
Special stains:Aeromonas, cryptosporidium & vibrio sp.
Duodenal aspirate & Biopsy: Giardia,
Isospora,cryptosporidium.
ELISA
E.M.
Colonoscopy & sigmoidoscopy.

47. DRUG INDUCED DIARRHOEA
Antibiotics
Laxatives
Antihypertensives
Lactulose
Antineoplastics
Antiretroviral drugs
Magnesium containing
compounds
Anti arrhythmics
NSAIDs
Colchicine
Antacids
Acid reducing agents
Prostaglandin analogs

48. Antibiotic-induced diarrhea
unexplained onset of diarrhea that occurs with the
administration of any antibiotic
due to disruption of normal intestinal flora, which
leads to
either proliferation of pathogenic microorganisms or
impairment of the metabolic functions of the
microflora

49. Endocrine causes
Diabetic autonomic neuropathy
Thyrotoxicosis
Neuroendocrine tumours
~ Zollinger Ellison syndrome
~ VIPoma
~ Somatostatinoma
~ Carcinoid syndrome
~ Medullary carcinoma of thyroid

51.  Hypokalaemia
 Depletional hyponatraemia
 Hypernatraemia
 Hypophosphataemia
 Hypomagnesemia
 Dehydration
 Hypovolaemic shock

53. Acute Diarrhoea : Management
Access Hydration Status
Encourage 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

54. Oral Rehydration Therapy
Sodium chloride 3.5 g
Trisodium citrate dehydrate 2.9 g
(or sodium bicarbonate 2.5g)
Potassium chloride 1.5g
Glucose 20 g
To 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.