Constipation

Question 1

What is constipation defined as?

Answer 1

Generalising <3 times a week bowel movement

1. Infrequent stools
2. Difficulty passing stool
3. Sensation of incomplete emptying
4. Anorectal blockage

Question 2

What are other symptoms of constipation?

Answer 2

1. Abdominal pain or discomfort
2. Distension
3. Bloating

Question 3

What are some symptoms in the elderly that are non-specific?

Answer 3

1. Confusion or delirium, functional decline
2. Nausea or loss of appetitie
3. Overflow diarrhoea
4. Urinary retention

Question 4

When should you suspect diagnosis of faecal loading or impact?

Answer 4

1. Hard, lumpy stools, which may be large and infrequent (for example passed every 7–10 days), or small and relatively frequent (for example passed every 2–3 days).
2. Having to use manual methods to extract faeces.
3. Overflow faecal incontinence, or loose stool

Question 5

What are possible causes of constipation?

Answer 5

1. Diet

2. Drug treatment

Question 6

What is the conservative management of constipation?

Answer 6

1. High fibre diet but increase gradually and aim for 30g

2. Lots of fluid intake

Question 7

What are different types of laxatives?

Answer 7

1. Bulk-forming laxatives
2. Osmotic laxatives
3. Stimulant laxatives
4. Prokinetic laxatives

Question 8

What is the aim of laxatives?

Answer 8

The aim of laxatives is to increase stool frequency or ease of stool passage by increasing stool water content (directly by osmotic or intestinal secretory mechanisms) or by accelerating bowel transit

Question 9

How do bulk forming laxatives work?

Answer 9

1. (containing soluble fibre) act by retaining fluid within the stool and increasing faecal mass
2. stimulating peristalsis
3. also have stool-softening properties.

Question 10

What are examples of bulk forming laxatives?

Answer 10

1. Ispaghula husk.
2. Methylcellulose.
3. Sterculia.

Question 11

How do osmotic laxatives work?

Answer 11

1. act by increasing the amount of fluid in the large bowel producing distension, which leads to stimulation of peristalsis
2. lactulose and macrogols also have stool-softening properties

Question 12

What are examples of osmotic laxatives?

Answer 12

1. Lactulose.
2. Macrogols (polyethylene glycols).
3. Phosphate and sodium citrate enemas.

Question 13

How do stimulant laxatives work?

Answer 13

cause peristalsis by stimulating colonic nerves (senna) or colonic and rectal nerves (bisacodyl, sodium picosulfate

Question 14

What are examples of stimulant laxatives>

Answer 14

1. Senna
2. Basacodyl and sodium picosulfate
3. Docusate

Question 15

How does Senna work?

Answer 15

hydrolyzed to the active metabolite by bacterial enzymes in the large bowel

Question 16

How does bisacodyl and sodium picosulfate work?

Answer 16

1. hydrolyzed to the same active metabolite
2. Bisacodyl is hydrolyzed by intestinal enzymes
3. sodium picosulfate relies on colonic bacteria.

Question 17

How does docusate work?

Answer 17

a surface-wetting agent which reduces the surface tension of the stool, allowing water to penetrate and soften it. Also has a relatively weak stimulant effect

Question 18

What is an example of a prokinetic laxative and how does it work?

Answer 18

Prucalopride — a selective, high-affinity, serotonin (5HT4) receptor agonist, which stimulates intestinal motility