Bowel obstruction

Question 1

What does constipation lead to?

Answer 1

nausea, malaise, abdominal pain, overflow diarrhoea

Question 2

What are the causes of constipation?

Answer 2

Drugs = opiates, ondansetron, anticholingerics, diuretics
Diet = lack of fibre, poor fluid intake
Reduced activity = sedentary life
Electrolyteimbalance = hypercalcaemia, hypokalaemia
Underlying conditions = cancer, hypothyroidism
Neurological conditions = SC compression

Question 3

What are the basics of managing constipation?

Answer 3

hard stools ==> needs softener
soft stools ==> needs stimulant
if impacted ==> movicol

Question 4

What are stimulant laxatives?

Answer 4

most act on large bowel
helpful in opiate induced constipation
can cause abdominal colic
contraindicated= complete obstrction due to risk of perforation

e. g. senna, bisacodyl
- danthron - turns urine orange/red and burns skin

Question 5

What are examples of stool softeners and osmotic laxatives?

Answer 5

softeners= docusate sodium = well tolerated

osmotic laxatives = act on small bowel - req good fluid intake e.g. lactulose or movicol

Question 6

What are some bowel interventions?

Answer 6

commonly required by pts esp on high dose opiates
Suppositories = bisacodyl (causes anorectal stimulation), glycerol (draws fluid into the rectum to soften and lubricate the stool)
enemas = phosphate or microlax

Question 7

What are some causes of malignant bowel obstruction?

Answer 7

extrinisic compression => tumour, omental mets, malignant adhesions, radiation, fibrosis
intraluminal occlusion => annular tumour
motility disorders => tumour infiltration of the mesentery

Question 8

When reviewing a pt with suspected bowel obstruction what are some key signs?

Answer 8

if pt has abdominal colic and bowel sounds == often mechanical component

if pt doesnt have colic and absent bowel sounds == likely paralytic component (ileus) or bowel not working but nothing causing a blockage

Question 9

How do you manage a malignant bowel obstruction if the pt isn’t suitable for surgery?

Answer 9

medical management

• pain/colic ==> opiates /buscopan
• N+V => SC antiemetics/antisecretory meds
• Dry mouth=> regular mouth care, ice chips, pineapple juice

Question 10

What antiemetics are commonly usedin malignant bowel obstruction?

Answer 10

metoclopromie is good for paralytic ileus - avoid in pts with colic as it can work pain and risk of perforation

if colic present then use levomepromazine, cyclizine or haloperidol

Question 11

What are some antisecretory medications?

Answer 11

buscopan
antimuscarinc and antisecretory
reduce vol of GI secretions
also antispasmodics for colic

octreotide
- works more quickly than buscopan, side efffect= dry mouth and more expensive