209 Constipation and IBS

Question 1

What is primary (functional) constipation?

Answer 1

Dysmotility due to mechanical problem

Never learnt

Question 2

What is secondary (organic) constipation?

Answer 2

Constipation due to obstruction

Question 3

What is obstruction defaecation syndrome?

Answer 3

Constipation perhaps due to chronic straining producing a stretching and redundancy of the distal rectum where compensation methods have ceased and evacuation has become impaired

Question 4

Name 3 causes of idiopathic constipation

Answer 4

IBS
Slow transit
Megacolon/megarectum

Question 5

Name 2 metabolic causes of chronic constipation

3 listed

Answer 5

Hypothyroidism
Hypercalcaemia
Hypokalaemia

Question 6

Name a neuromuscular disease which can cause chronic constipation

Answer 6

Hirschsprungs

Question 7

How can anorectal physiology be assessed/investigated?

Answer 7

Manometry

Balloon inflation - i.e. rectal sensation studies

Question 8

What does 5 or fewer markers remaining on day 5 (AXR) following colonic transit studies suggest?

Answer 8

Normal GIT transit

Question 9

Why do pts with DM become constipated?

Answer 9

Due to chronic dysmotility and slow transit

Question 10

Which CNS diseases can develop constipation?

4 listed

Answer 10

Parkinsons
MS
CVA
Spinal injuries

Question 11

Name 4 types of drugs which can cause constipation

7 listed

Answer 11

Narcotics
Iron supplements
Non magnesium antacids
Calcium channel blockers
Inadequate thyroid hormone replacement 
Psychotropic drugs
Anticholinergic drugs

Question 12

What diagnostic criteria is used to diagnose IBS?

Answer 12

Rome II

Question 13

What is the MOA of bulk forming laxatives?

Answer 13

Retain fluid in stool to increase faecal mass and stimulate peristalsis and soften stool

Question 14

What is the MOA of osmotic laxatives?

Answer 14

Increase the fluid in the large bowel –> producing distension leading to stimulation of peristalsis.
Also has stool softening properties

Question 15

What is the MOA of stimulant laxatives? (esp Senna)

Answer 15

Stimulate colonic and rectal nerves.

Senna is hydrolysed in the large bowel by bacteria into active metabolite

Question 16

What is the MOA od surface-wetting agents?

Answer 16

Reduce the surface tension of of the stool allowing water to penetrate and soften it

Question 17

What are fcyclomine and hyoscine used for in chronic constipation?

Answer 17

Pain management - they’re antispasmotics.

Relaxes SM but might aggravate the constipation

Question 18

How may antidepressants help constipation?

Answer 18

Affect serotonergic signalling but have variable anticholinergic activity

Question 19

When would patients taking probiotics typically see an improvement in their constipation?

Answer 19

Within 6 weeks

Question 20

What type of drug is Lubiprostone? (treatment of constipation)

Answer 20

Chloride channel activator - works in the luminal side to stimulate chloride secretion and water secretion into the lumen - soften stool, increase motility and promote spontaneous bowel movement

Question 21

What are the 3 surgical options for dysmotility?

Answer 21

1. Colectomy and iliorectal anastomosis
2. SNS (sacral nerve stimulation)
3. ACE procedure - antegrade colonic enema

Question 22

What is the important consideration when deciding about colectomy (functionally)?

Answer 22

Normal small bowel motility - incase of need of temporary ileostomy.

Question 23

What is SNS used for?

Answer 23

Faecal incontinence

Question 24

What causes obstructed defaecation?

Answer 24

Chronic straining producing stretching and redundency of the distal rectum + pelvic problems

Question 25

What commonly precedes rectocoele causing obstructed defaecation?

Answer 25

Childbirth

Question 26

What are the 3 indications for surgery to treat obstructed defaecation?

Answer 26

External prolapse Rectocoele Rectal intersusseption

Question 27

Which Surgery is more suitable for older patients to treat obstructed defaecation? - Open rectopexy - Perineal procedure

Answer 27

Perineal procedure

Question 28

Which imaging method is 90% sensitive for lesions >1cm?

Answer 28

CT colonography

Question 29

Which imaging method is good for visualising the mesorectal fascia?

Answer 29

MRI

Question 30

Which imaging technique is useful for functional imaging of tumours?

Answer 30

PET scan

Question 31

What does adenoma in the colon look like?

Answer 31

Cauliflower

Question 32

Where are mets usually found with colorectal cancers?

Answer 32

Liver and lungs

Question 33

Which important structure is commonly involved in rectal cancer?

Answer 33

Mesorectal fascia

Question 34

What is T1 stage rectal cancer?

Answer 34

Confined to the mucosa + muscularis mucosa must be intact

Question 35

What is T2 stage rectal cancer?

Answer 35

Submucosa and mucosa also compromised

Question 36

What is T3 stage rectal cancer?

Answer 36

Cancer extending beyond the muscularis mucosa

Question 37

What is T4 stage rectal cancer?

Answer 37

Involvement of other organs/structures

Question 38

What is ERUS?

Answer 38

Endorectal ultrasound

Question 39

What are the downfalls of ERUS?

Answer 39

Sometimes cant pass the probe Field of view small Operator dependant

Question 40

What is the initial treatment of constipation?

Answer 40

Dietary and fluid intervention

Question 41

What is the daily recommended intake of fibre?

Answer 41

18-30g

Question 42

What pharmacological intervention is the 1st line treatment after dietary and fluid intervention has been unsuccessful in the treatment of constipation?

Answer 42

Bulk forming laxatives

Question 43

What is the secondary pharmacological treatment if bulk forming laxatives have been unsuccessful in the treatment of constipation?

Answer 43

Osmotic laxatives ( if the stool remains hard)

Question 44

When should a stimulant laxative be prescribed?

Answer 44

If the stool has softened but patient still finds them difficult to pass or complains of inadequate emptying

Question 45

When should the macrogol, Arachis oil enema not be used?

Answer 45

If the patient has a peanut allergy

Question 46

When should the macrogol, phosphate enema be used with caution?

Answer 46

When renal impairment or HF