Constipation

Question 1

What is the general definition of constipation?

Answer 1

Passage of =2 bowel movements/week, with a sense of straining, pain or incomplete evacuation

Question 2

What might constipation + rectal bleeding indicate?

Answer 2

Cancer

Question 3

What might constipation + distention + active bowel sounds indicate?

Answer 3

Stricture/obstruction

Question 4

What might constipation + menorrhagia indicate?

Answer 4

Hypothyroidism

Question 5

What would you consider asking someone who was presenting with constipation?

Answer 5

• Frequency/nature/constistency?
• Recent change?
• Blood/mucus?
• Diarrhoea as well as constipation?
• Digitating rectum/vagina to pass stool?
• Diet
• Drugs

Question 6

What is essential to do when examining someone with constipation?

Answer 6

PR exam

Question 7

What anorectal disease can cause constipation?

Answer 7

• Anal/colorectal cancer
• Fissures
• Rectal prolapse
• Proctalgia fugax
• Mucosal ulceration
• Pelvic muscle/levator ani dysfunction

Question 8

What are causes of intestinal obstruction which can cause constipation?

Answer 8

• Colorectal cancer
• Strictures
• Pelvic mass
• Diverticulosis
• Pseudo-obstruction

Question 9

What are metabolic/endocrine causes of constipation?

Answer 9

• Hypercalcaemia
• Hypothyroidism
• Hypokalaemia
• Porphyria
• Lead poisoning

Question 10

What drugs can cause constipation?

Answer 10

• Opiates
• Anticholinergics
• Iron
• Antacids
• Diuretics
• CCBs

Question 11

What neuromuscular problems can cause constipation?

Answer 11

• Spinal/nerve injury
• Systemic sclerosis
• Diabetic neuropathy
• Hirschsprung’s disease
• Chagas disease

Question 12

What are general causes of constipation?

Answer 12

• Poor diet +/- lack of exercise
• Dehydration
• IBS
• Old age
• Post-operative pain

Question 13

What investigations might you perform in someone with constipation?

Answer 13

None in those who are young - consider investigating if red flag symptoms:

• Bloods - FBC, ESR, U+E’s, Ca2+, TFTs
• Other - Colonoscopy + biopsy

Question 14

What lifestyle advice would you give someone with constipation?

Answer 14

Reassurance

• Drink more
• Exercise more
• High-fibre diet

Question 15

What medications can be used to aid constipation?

Answer 15

• Bulking agents
• Stimulant laxatives
• Stool softeners
• Osmotic laxatives

Question 16

What are bulking agents?

Answer 16

Bulk forming laxatives consist of indigestible polysaccharides which increase faecal mass. This in turn stimulates the stretch receptors in the bowel mucosa which increases peristalsis and defaecation.

Question 17

What conditions are bulk forming laxatives most useful in?

Answer 17

• IBS
• Diverticulitis
• Those with colostomies/ileostomies

Question 18

What are examples of bulk forming agents?

Answer 18

• Dietary fibre
• Wheat bran
• Methylcellulose
• Mucilaginous gums – sterculia
• Mucilaginous seeds and seed coats, e.g. ispaghula husk
• Normacol

Question 19

How do stool softeners work?

Answer 19

Soften the stools making them easier to pass. Arachis oil is a mixture of peanut and ground-nut oil. It is given as an enema in patients with faecal impaction. It works in two ways. It softens the stool and acts as a lubricant.

Question 20

What conditions are stool softeners most commonly used in?

Answer 20

Managing painful anal conditions e.g. fissures, haemorrhoids

Question 21

What are examples of osmotic laxatives?

Answer 21

• KleanPrep
• Movicol
• Sodium Picosulphate (Picolax)
• Lactulose
• Phosphate enema

Question 22

How do osmotic laxatives work?

Answer 22

Increase the amount of water in the large bowel, either by drawing fluid from the body into the bowel or by retaining the fluid they were administered with due to osmotic gradient created by the drug

Question 23

Why is lactulose useful in hepatic encephalopathy?

Answer 23

Produces low faecal pH, that discourages ammonium producing bacteria from growing

Question 24

When are phosphate enemas used?

Answer 24

Rapid bowel evacuation prior to procedures

Question 25

How do stimulant laxatives work?

Answer 25

**Increase intestinal motility** - speculated that they both act as osmotic laxative and stimulate myenteric plexus

Question 26

When would you not use stimulant laxatives in someone with contipation?

Answer 26

If it was caused by intestinal obstruction or acute colitis

Question 27

What can occur if you use stimulant laxatives for prolonged periods?

Answer 27

Colonic atony

Question 28

What are examples of stimulant laxatives?

Answer 28

* **Phenolphthalein** * **Bisacodyl** * **Anthraquinones – senna and dantron (only for the terminally ill)** * **Docusate sodium** * **Methylnaltrexone (for opioid induced constipation)** * **Lubiprostone** * **Prucalopride** * **Linaclotide** * **Sodium picosulfate**

Question 29

How would you manage constipation?

Answer 29

* **Lifestyle advice** * **Consider medications/evacuation measures** * **Treat cause**

Question 30

What enemas are used in those with constipation?

Answer 30

* **Arachis oil** * **Docusate sodium** * **Hypertonic phosphate** * **Sodium citrate**