Diarrhoea

Question 1

Acute vs chronic

Answer 1

Chronic:
3 or more loose stools daily for at least >4 weeks

Persistent: 2-4 weeks

Acute: <2 weeks

Question 2

Volume of poop and typical location of concern

Answer 2

High volume: small bowel / right colon (fluid reabsorption compromised) (secetaory diarrhoea)

Low volume: left colon / rectum (stool reservoir, reduced ability to hold on, irritability)

Question 3

Causes of acute vs chronic

Answer 3

Acute
1. Infection
-Bacterial (salmonella, E coli, shigella, Yersinia etc)
-viral (Norovirus, rotavirus, adenovirus, CMV)
-parasite (Giardia, cryptosporidium)

Chronic
1. Inflammatory
(damaged epithelium leads to exudate)

2. Osmotic
   - Osmotically active compound in lumen of bowel draws fluid in
3. Secetory
   - Stimulation excess fluid secretion
4. Fatty
   - Malabsorption

**BLOOD = inflammation or fissures etc

Question 4

Sources of some infections

Answer 4

• Raw seafood
  – Norovirus,vibrio hepatitisA
• Raw eggs
  – Salmonella
• Undercooked meat, chicken
• Salmonella, Campylobacter, E.Coli, Hepatitis E (pork)
• Unpasteurized milk
  – Salmonella, campylobacter, yersinia
• Unpasteurized soft cheese
  – Above+Listeria
• Healthcare setting
  – C.diff

Question 5

How to know if infection is bacterial or protozoa or viral

Answer 5

Bacterial symtpoms occur in 12-72 hours incubation

Protozoa: Long incubation

** toxin in food <6 hours for incubation, eg staph aureus

Viral: short incubation

Question 6

Mechanism of diarrhoea

Answer 6

• Inflammatory – mucosal inflammation (bleeding) – exudate
• Giardia
  – osmotic diarrhoea (osmotic pull into lumen causes water loss)
  – Villous atrophy, carbohydrate malabsorption, undigested sugars draw fluid in
  ↳ similar to what you sometimes see in coeliac disease
• E.Coli – secretory diarrhoea.
  -Toxin stimulates excessive fluid secretion

Question 7

Other causes of diarrhoea
- Infectious
-Non infectious

Answer 7

• Infectious
  1. Any sepsis
  – Meningococcaemia – Atypical pneumonia – Malaria
• Pelvic inflammatory disease
• Diverticulitis

-Non infectious
IBD
Bowel cancer
Overflow constipation

DKA/thyrotoxicosis
Uraemia
Neuroendocrine tumours

Drugs:
NSAIDs
Abx
PPI
Chemotherapy agents

Question 8

Chronic Inflammatory diarrhoea
- causes

Answer 8

• IBD
  – UC, Crohn’s
• Diverticulitis
• SIBO (small intestinal bacterial overgrowth)
• Radiation colitis
• Ischemic colitis
• Colon cancer

Question 9

Osmotic diarrhoea -causes

Answer 9

• Carbohydrate malabsorption
  – Lactose intolerance due to lactase deficiency – Irritable bowel syndrome
• Coeliac disease
  – Villous abnormality
• Small intestinal bacterial overgrowth
  – Malabsorption of proteins, carbohydrates, fats and other
  – Osmotically active by-products of bacteria metabolism
• Laxative abuse

Question 10

Secetory diarrhoea
-cause

Answer 10

• Terminal ileal resection
• Cholecystectomy
  – Bile flow continuous into small intestine
• SIBO
  Unabsorbed food products and bile acids stimulate secretory cella in the colon
• Microscopic colitis
  –Lymphocytic colitis and collagenous colitis
• Inflammatory bowel disease
• Neuroendocrine tumours
  – Hormones that drive water secretion e.g.carcinoid–serotonin

Question 11

Fatty Diarrhoea causes

Answer 11

• Pancreatic exocrine insufficiency
  – Inadequate pancreatic enzymes
• Bile acid malabsorption
  – Inadequate amount of bile acids
• Small intestinal bacterial overgrowth
  – Deconjugation of bile acids – impaired micelle formation – impaired fat digestion and absorption
• Coeliac disease
  – Mucosal disease villous
  atrophy/inflammation
• Short bowel syndrome
  – Not enough mucosal surface

Question 12

SIBO Causes

Answer 12

• Excessive amounts of colonic bacteria in the small intestine
  – Bloating, flatulence, abdominal discomfort, wide range
  – Diarrhoea, steatorrhea, malabsorption
  Predisposed By:
  – Impaired motility–the migrating motor complex is a mechanism of preventing SIBO by cleansing the small bowel of
  debris
• Scleroderma, diabetes, opiate use
• Anatomic disorders – stasis in the small intestine
  – Adhesions, strictures, small intestinal diverticula,
  – Blind loops (e.g. post-surgical)
• Metabolic / systemic diseases
• Immune deficiency disorders

Question 13

Mechanism of SIBO

Answer 13

• Maldigestion
  – Bacteria deconjugates bile acids leading to impaired micellar formation and fat digestion
  – Bacterial degradation of carbohydrates in the intestinal lumen, which also produces osmotically
  active by-products
  – Bacterial degradation of protein precursors in the intestinal lumen
• Malabsorption
  – Bile acids, fats, carbohydrates, proteins, B12 (bacteria competes for B12)
  – Damages enterocytes by direct adherence, producing enterotoxins and enzymes

Question 14

How does malab or maldigestion cause types of chronic diarrhoea

Answer 14

• Fatty diarrhoea
  – Deconjugation of bile acids – impaired micelle formation – impaired fat digestion and absorption
• Inflammatory diarrhoea
  – Bacteria causes direct inflammation of enterocytes
• Osmotic diarrhoea
  – Malabsorption of proteins, carbohydrates, fats and other osmotically active by-products of bacteria
  metabolism
  – Deconjugated bile acids inhibit carbohydrate transporters
• Secretory diarrhoea
  – Unabsorbed food products and bile acids can stimulate secretory cells in the colon