Surgical Management of the GI Tract

Question 1

What is the pattern of vomiting in small bowel obstruction?

Answer 1

Early and profuse vomiting

Question 2

What signs are revealed in an erect abdominal X-ray in a patient with a large bowel obstruction?

Answer 2

Fluid accumulation within the bowel (white is fluid, black is air)

Distended oval gas shadow, looped on itself to give typical ‘bent inner tube sign’ or coffee bean sign’

• Haustra do not extend across the width of the gas shadow, suggesting this is of the large intestine.
• Typical appearance of volvulus of the sigmoid colon- intestinal twisting causes obstruction (flatus and gas accumulation).

Question 3

A coffee bean sign on an abdominal X-ray reveals what type of bowel obstructon?

Answer 3

Large bowel obstruction

Question 4

What is the pattern of haustra on an abdominal X-ray of a large bowel obstruction?

Answer 4

Haustra do not extend across the width of the gas shadow

Question 5

What is a sigmoid volvulus?

Answer 5

Intestinal twisting causing obstruction

Question 6

What is the management of a sigmoid volvulus?

Answer 6

A sigmoidoscope is passed with the patient lying in the left lateral position.

• A large well lubricated, soft rubber rectal tube is passed along the sigmoidoscope
• This helps to untwist the volvulus, with release of vast quantities of flatus and liquid faeces – alleviating the intestinal obstruction.

Question 7

How does a sigmoidscope work with treating a sigmoid volvulus?

Answer 7

• A large well lubricated, soft rubber rectal tube is passed along the sigmoidoscope
• This helps to untwist the volvulus, with release of vast quantities of flatus and liquid faeces – alleviating the intestinal obstruction

Question 8

Which artery is implicated in sigmoid necrosis?

Answer 8

Inferior mesenteric artery would be impaired due to torsion, subsequently undergoing necrosis

• Impair blood flow to the affected segment, manifesting as an oedematous bowel
• An oedema overcomes the pressure of arterial inflow

Question 9

What is a Hartmann’s procedure?

Answer 9

Involved in resecting the necrosed colon, and is distally sealed off via an end colostomy - stoma

Question 10

What are the symptoms of acute mesenteric ischaemia?

Answer 10

• Central pain with guarding and abdominal distention
• Hypotension
• Cyanosis
• Absent bowel sounds – There is tickling in obstruction
• Raised serum lactate – Metabolic acidosis indicates a late sign of ischaemic bowel.

Question 11

What serum level is expected in an individual with acute mesenteric ischaemia?

Answer 11

Raised lactate

Question 12

What are the risk factors fo acute mesenteric ischaemia?

Answer 12

Atherosclerosis causing vessel occlusion and smoking increasing the risk of cardiovascular disease.

Question 13

What investigation is conducted in a patient with suspected mesenteric ischaemia?

Answer 13

CT of the abdomen and pelvis with contrast, this will detect regions which are underperfused in comparison to a healthy bowel

-Demonstrate thrombus in mesenteric arteries and veins

Abnormal enhancement of bowel wall

Presence of embolus or infarction of other organs

Question 14

What are the three main common causes of an acute mesenteric ischaemia?

Answer 14

Embolism - 50%
Thrombosis - 20-35%
Venous (10-15%)

Question 15

Why are the common causes of an acute mesenteric ischaemia due to an embolism?

Answer 15

From left auricle to atrial fibrillation
A mural infarct - a clot in the wall of the ventricle

Atheroma from aorta of aneurysm

Endocarditis vegetations

Left atrial myoxma

Question 16

Why does thrombosis cause acute mesenteric ischaemia?

Answer 16

Block’s origin of superior mesenteric artery and cause ischaemia of full length of small bowel -due to atherosclerosis.

Thrombosis typically occurs in main splanchnic vessels.
• Coeliac, superior and inferior MAs.
Nonocclusive (<5%) – Hypotension//hypoperfusion
• Vasospasm in shock – Nonocclusive mesenteric ischaemia
• Vasopressor requirements and those undergoing dialysis with large volume fluid removal.

Question 17

How is the location of an embolus detected?

Answer 17

Arterial phase CT scan

Question 18

What does an arterial phase CT scan reveal?

Answer 18

Reveals zones of oxygenation (white rings)

The non-enhancing fluid, filled ischaemic small bowel loops suggest hypoperfusion

Question 19

What is the main management of an acute mesenteric ischaemia?

Answer 19

Emergency exploratory laparotomy
Arterial bypass of SMA
Endovascular management of SMA thrombus
Damage control laparotomy

Question 20

What is emergency exploratory laparotomy?

Answer 20

Midline incision, evaluate abdominal visceral and resect intestinal necrosed bowel.
• Restoration of SMA blood flow and resection of nonviable bowel: Embolectomy of SMA.