209 Constipation and IBS Flashcards Preview

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Flashcards in 209 Constipation and IBS Deck (46)
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1
Q

What is primary (functional) constipation?

A

Dysmotility due to mechanical problem

Never learnt

2
Q

What is secondary (organic) constipation?

A

Constipation due to obstruction

3
Q

What is obstruction defaecation syndrome?

A

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

4
Q

Name 3 causes of idiopathic constipation

A

IBS
Slow transit
Megacolon/megarectum

5
Q

Name 2 metabolic causes of chronic constipation

3 listed

A

Hypothyroidism
Hypercalcaemia
Hypokalaemia

6
Q

Name a neuromuscular disease which can cause chronic constipation

A

Hirschsprungs

7
Q

How can anorectal physiology be assessed/investigated?

A

Manometry

Balloon inflation - i.e. rectal sensation studies

8
Q

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

A

Normal GIT transit

9
Q

Why do pts with DM become constipated?

A

Due to chronic dysmotility and slow transit

10
Q

Which CNS diseases can develop constipation?

4 listed

A

Parkinsons
MS
CVA
Spinal injuries

11
Q

Name 4 types of drugs which can cause constipation

7 listed

A
Narcotics
Iron supplements
Non magnesium antacids
Calcium channel blockers
Inadequate thyroid hormone replacement 
Psychotropic drugs
Anticholinergic drugs
12
Q

What diagnostic criteria is used to diagnose IBS?

A

Rome II

13
Q

What is the MOA of bulk forming laxatives?

A

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

14
Q

What is the MOA of osmotic laxatives?

A

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

15
Q

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

A

Stimulate colonic and rectal nerves.

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

16
Q

What is the MOA od surface-wetting agents?

A

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

17
Q

What are fcyclomine and hyoscine used for in chronic constipation?

A

Pain management - they’re antispasmotics.

Relaxes SM but might aggravate the constipation

18
Q

How may antidepressants help constipation?

A

Affect serotonergic signalling but have variable anticholinergic activity

19
Q

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

A

Within 6 weeks

20
Q

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

A

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

21
Q

What are the 3 surgical options for dysmotility?

A
  1. Colectomy and iliorectal anastomosis
  2. SNS (sacral nerve stimulation)
  3. ACE procedure - antegrade colonic enema
22
Q

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

A

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

23
Q

What is SNS used for?

A

Faecal incontinence

24
Q

What causes obstructed defaecation?

A

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

25
Q

What commonly precedes rectocoele causing obstructed defaecation?

A

Childbirth

26
Q

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

A

External prolapse
Rectocoele
Rectal intersusseption

27
Q

Which Surgery is more suitable for older patients to treat obstructed defaecation?

  • Open rectopexy
  • Perineal procedure
A

Perineal procedure

28
Q

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

A

CT colonography

29
Q

Which imaging method is good for visualising the mesorectal fascia?

A

MRI

30
Q

Which imaging technique is useful for functional imaging of tumours?

A

PET scan

31
Q

What does adenoma in the colon look like?

A

Cauliflower

32
Q

Where are mets usually found with colorectal cancers?

A

Liver and lungs

33
Q

Which important structure is commonly involved in rectal cancer?

A

Mesorectal fascia

34
Q

What is T1 stage rectal cancer?

A

Confined to the mucosa + muscularis mucosa must be intact

35
Q

What is T2 stage rectal cancer?

A

Submucosa and mucosa also compromised

36
Q

What is T3 stage rectal cancer?

A

Cancer extending beyond the muscularis mucosa

37
Q

What is T4 stage rectal cancer?

A

Involvement of other organs/structures

38
Q

What is ERUS?

A

Endorectal ultrasound

39
Q

What are the downfalls of ERUS?

A

Sometimes cant pass the probe
Field of view small
Operator dependant

40
Q

What is the initial treatment of constipation?

A

Dietary and fluid intervention

41
Q

What is the daily recommended intake of fibre?

A

18-30g

42
Q

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

A

Bulk forming laxatives

43
Q

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

A

Osmotic laxatives ( if the stool remains hard)

44
Q

When should a stimulant laxative be prescribed?

A

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

45
Q

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

A

If the patient has a peanut allergy

46
Q

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

A

When renal impairment or HF