1. Recurrent abdominal pain 2. Changes with defecation 3. Change in stool consistency (Bristol chart) Must be chronic (3-6 months)

1. Explain no evidence of cancer, inflammation 2. Don’t say its all in your head, say “Sensitive gut”

Intestine Physiology Flashcards by Robert Donohoe

What senses content of the duodenum

Vagal afferents
I cells and S cells (apical surface)

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I cells secretion

CCK

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S cells secretion

Secretin

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What do I cells sense

Fat/protein in duodenum lumen

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What do S cells sense

pH (HCl)

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CCK and secretin functions

Inhibit gastric emptying
Inhibit gastric acid secretion

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Enterochromaffin cell secretion

Serotonin

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How do anti-nausea meds work

Decreased serotonin (some by inhibiting enterochromaffin)

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Enterochromaffin-like cell secretion

Histamine

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Coeliac Genetic Rule-out Test

Two genes that almost all Coelaic have = rules out if negative (but non Coelaic also have it, so doesnt confirm Coelaic if positive)

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Coeliac Symptoms

Can be anything!

Mostly IBS, nausea, vomiting, steatorrhoea etc

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Coeliac Blood Test

Anti-TTG IgA
- Must be eating gluten when doing it = can be harmful

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Gold standard for coeliac

Biopsy of small intestine
- Take from many (8) locations

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Even if asymptomatic why should Coelaics not have gluten

Inflammation builds over time = in long term as elderly will lead to malabsorption problems in the small intestine
- Micronutrients first

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Genetic markers for Coelaic

DQ2 DQ8

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DGBI

Disorder of gut-brain interaction
- Tests normal but still symptoms and disease

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IBS location

Any part of the GI tract

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Causes of IBS

Many reasons (Microbiome, stress, mucosa etc), not 100% sure

Main cause is visceral hypersensitivity

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Microbiome of IBS

Increased enterobacteriacaea

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IBS severity

Low mortality

Very high morbidity - time off work, social stigma

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IBS symptom criteria

Recurrent abdominal pain
Changes with defecation
Change in stool consistency (Bristol chart)

Must be chronic (3-6 months)

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Types of IBS

IBS-C (constipation, hard stools)
IBS-D (diarrhoea, watery stools)
IBS-M (mixed, hard and watery stools)
IBS-U (unclassified)

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What symptoms suggest it might be something more than IBS

Rectal bleeding
Iron deficiency
Weight loss
Vomiting
Familial history of other disease eg Coelaic, colorectal cancer

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IBS Management

Explain no evidence of cancer, inflammation
Don’t say its all in your head, say “Sensitive gut”

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FODMAP Diet

Fermentable sugars

If IBS what diet should you consider

Low FODMAP (but dont cut out all FODMAP as need a diverse diet)

Why might you give someone with ‘diarrhoea’ laxatives / fibre

They have hard stools blocking the colon, and only the watery stools can actually get out. But the root of the problem is the constipation from hard stools

Gut-brain neuromodulators

TRC SSRI Anti-depressants change the way your body responds to discomfort

IBD vs IBS

Inflammable Bowel Disease v Irritable Bowel Syndrome

IBD risk groups

30s, and 60s Non-Maori

Cause of IBD

Environmental factors in genetically susceptible individuals - Western diet - Antibiotics in childhood - Smoking Crohn’s

Symptoms of IBD

Diarrhoea - frequency, urgency Blood in stool Tenesmus

Tenesmus

Incomplete defecation

Where else does IBD present other than the bowel

Eyes, skin, joints

Types of IBD

Ulcerative Colitis Crohns

Ulcerative Colitis

Limited to colon Inflammation down whole colon

Crohn’s

Any part of the GI tract, mainly colon and ileum Inflammation Narrowing Fistula = joining Perianal fissures

Different symtpoms of Chrons and Ulcerative colitis

UC - Always diarrhoea, bleeding Chrons - Not always diarrhoea, bleeding = harder to detect

Normal stools on the Bristol Stool Chart

2-4

As Bristol Stool number increases, what happens to consistency

More loose

Acute Diarrhoea cause

Infection!

Chronic diarrhoea types

1. Inflammatory 2. Osmotic 3. Secretory 4. Fatty

If blood in diarrhoea what type is it

Inflammatory

Campylobacter causes ______ diarrhoea

Inflammatory

Giardia causes ______ diarrhoea

Osmotic

E. coli causes ____ diarrhoea

Secretory

Main cause of acute diarrhoea

Campylobacter

Inflammatory Diarrhoea cause

Inflammation of the bowels = rupture to mucosa - eg IBD Coeliac cancer

What causes osmotic diarrhoea

Fluid drawn into lumen (eg. By lactose, IBS, Coeliac)

What causes secretory diarrhoea

Bile acid in the lumen = H2O secretion increased = diarrhoea

What causes fatty diarrhoea

Undigested fat in stool

SIBO stands for

Small intestinal bacterial overgrowth

What types of diarrhoea caused by SIBO

All

Ileostomy

Ilium diverted to outside of body, circumvent the anus = need holding bag

How much fluid consumed / excreted daily

8.5L consumed 6.5L absorbed by small int 2L absorbed by large int ~100mL excreted

Small intestine electrolyte secretion

HCO3-

Large intestine electrolyte secretion

K+ and HCO3-

Transcellular movement

Across two membranes, therefore must be active across at least one Solutes

Paracellular Movement

Passive via tight junctions

Where does absorption of water mostly occur

Jejunum

How does Na+ absorption occur

Exchanges and cotransporters down conc grad into cell

How does Cl- absorption occur

Follows Na+ absorption for charge balance By exchangers (with HCO3-) and absorption on its own

What does CFTR do

Active channel that moves Cl-

What regulates absorption and secretion

Mainly Aldosterone Also enteric nervous system, paracrine hormones etc

Difference between secretory and osmotic diarrhoea

Secretory =contents added to the lumen eg Na+ causing solvent drag Osmotic = contents remain in the lumen from malabsorption

How does oral rehydration therapy work

Na+ and glucose absorbed = Cl- absorbed to balance charge = H2O absorbed due to osmotic gradient = Less diarrhoea

What is a polyp

Circumscribed growth projecting above the mucosa Can be neoplastic or not

Types of non neoplastic polyps

Hyperplastic (common) Inflammatory

Adenoma

Pre-malignant polyp

Types of adenomas

Tubular (common) Villus Tubulovillous

Main risk factor for neoplastic adenoma becoming carcinoma

Size of the polyp (larger = increased risk)

Adenocarcinoma leads to which nutrient deficiency

Iron, due to chronic bleeding

How to stage tumours

TNM T - Extent of invasion of bowel wall N - Number of lymph nodes M - Metastatic?

Familial Polyposis Syndromes lead to higher rates of carcinomas because

Higher likelihood of adenoma becoming carcinoma (no increase in numbers of polyps themselves)