Bowel Obstruction

Question 1

Give some causes of small bowel obstruction

Answer 1

Adhesions
Hernia - incarcerated
Gallstone ileus
Tumours (ileocecal junction)

Question 2

Give some causes of large bowel obstruction

Answer 2

Colorectal tumours
Sigmoid volvulus
Chronic diverticular disease
Acute diverticular disease

Question 3

Define mechanical obstruction

Answer 3

Physical obstruction of a part of the bowel

Question 4

How does a sigmoid volvulus appear on plain radiograph?

Answer 4

Inverted U or rugby ball

Question 5

What happens in closed loop obstruction?

Answer 5

The ileocaecal valve prevents reflux of the large bowel contents, so the large bowel contents distend the caecum

Question 6

Define a functional obstruction

Answer 6

Signs of a physical obstruction but there isn’t one. Usually occur post-surgery or from metabolic disorders.

Question 7

Describe paralytic ileus

Answer 7

Obstruction of the intestine due to paralysis of the intestinal muscles

Question 8

What can cause paralytic ileum?

Answer 8

Peritonitis
Blood in the abdomen
Opiates
Handling of the bowel during surgery 
Electrolyte imbalance (hypokalaemia)

Question 9

How do you resolve paralytic ileum?

Answer 9

Treat the cause

Question 10

What is pseudo-obstruction?

Answer 10

Symptoms of mechanical obstruction are present but there is no cause found.

Question 11

What causes pseudo obstruction?

Answer 11

Trauma (injury to the smooth muscle or nervous system)
Anti-cholinergic drugs
Anti-parkinsonism drugs
Renal failure

Question 12

How will someone with an intestinal obstruction present?

Answer 12

Abdominal pain (colicky)
Vomiting
Absolute constipation
Dysphagia
Abdominal distension

Question 13

What symptoms are more prevalent in small bowl obstruction?

Answer 13

Vomiting first
Less abdominal distension
Pain is felt higher up in the abdomen

Question 14

What symptoms are more prevalent in large bowel obstruction?

Answer 14

More gradual onset
More normal bowel sounds
Constipation occurs first and then faeculant vomiting
Rectal bleeding

Question 15

What investigation would you not do for an obstruction or perforation?

Answer 15

Contrast study as it could leak into the abdomen.

Question 16

What investigations would you do for an obstruction?

Answer 16

FBC, U+Es - electrolyte imbalance
AXR
CT scan

Question 17

What are the supportive measure for bowel obstruction?

Answer 17

NBM
NG tube to decompress the stomach
Analgesia
IV Fluids

Question 18

How can you detect improvement with supportive management?

Answer 18

Decreasing nasogastric aspirates
Decreasing pain
Passage of flatus

Question 19

When would you perform surgery in obstruction?

Answer 19

Strangulation
Closed loop obstruction
Failure of conservative therapy
Tumour

Question 20

Define closed loop obstruction

Answer 20

Two points of the bowel are obstruction in a single location, which leads to the formation of a closed loop.

Question 21

What is a Hartmann’s Procedure?

Answer 21

Resection of the rectosigmoid colon with closure of the rectal stump and the formation of an end colostomy.

Question 22

What is the difference between closed loop and open loop obstruction?

Answer 22

Closed - competent ileocaecal valve, so pressure keeps increasing which can lead to bowel wall ischaemia, necrosis and perforation.

Open - incompetent ileocaecal valve, so there is relief of colonic pressure and the contents reflux into the ileum so can present like a small bowel obstruction

Question 23

What is the prognosis for large bowel obstructions?

Answer 23

Overall mortality = 10%

Caecal perforation and faecal peritonitis = 20% mortality