Intestinal ischaemia

Question 1

What is intestinal ischaemia?

Answer 1

Intestinal ischaemia is a medical condition in which injury to the large or small intestine occurs due to not enough blood supply

Question 2

What are the symptoms of intestinal ischaemia?

Answer 2

Abdominal pain
Nausea
Vomiting
Diarrhoea 
Tachycardia 
Rectal bleeding

Question 3

What are signs of Acute mesenteric ischaemia?

Answer 3

A striking feature is that the physical findings are out of proportion to the degree of pain

In the later stages typical symptoms of peritonism develop, with rebound guarding and tenderness

Question 4

Wat investigations would you do if you suspected Acute mesenteric ischaemia?

Answer 4

CT angiography is the gold standard and shows arterial blockage due to emboli or thrombus

A high level of suspicion and early diagnosis with CT angiography are the key to lower mortality rates.

Raised white cell count and the presence of metabolic acidosis may be found

Question 5

How would you manage Acute mesenteric ischaemia?

Answer 5

Initial resuscitation with intravenous fluids and oxygen should be carried out.

Intravenous broad-spectrum antibiotics are recommended.

Unless contra-indicated, intravenous unfractionated heparin is also recommended.

The goals of surgery include re-establishment of the blood supply to the ischaemic bowel; resection of all non-viable regions and preservation of all viable bowel.

Question 6

What is the prognosis for Acute mesenteric ischaemia?

Answer 6

Even in the best hands, the outcome is poor. If the diagnosis is missed, the mortality rate is 90%. With treatment, the mortality rate is still 50-90%

Question 7

What causes Acute mesenteric ischaemia?

Answer 7

1. Conditions causing arterial emboli
2. Conditions causing arterial thrombosis (atherosclerosis)
3. NOMI - hypotension, vasopressive drugs, ergotamines, cocaine, digitalis.
4. Hypercoagulability disorders

Question 8

What is Chronic mesenteric ischaemia?

Answer 8

This is a chronic atherosclerotic disease of the vessels supplying the intestine. It is also known as intestinal angina.

Usually all three major mesenteric arteries are involved.

Question 9

What are the risk factors for Chronic mesenteric ischaemia?

Answer 9

This is generally caused by factors predisposing to atherosclerosis - eg, smoking, hypertension, diabetes mellitus and hyperlipidaemia

Question 10

How does chronic mesenteric ischaemia present?

Answer 10

Moderate-to-severe colicky or constant and poorly localised pain

The history is typically one of weight loss, postprandial pain (‘intestinal angina’) and a fear of eating

There is usually a history of cardiovascular disease such as myocardial infarction or cerebral vascular disease

Other nonspecific symptoms may include nausea, vomiting, or bowel irregularity.

Question 11

What does examination in chronic mesenteric ischaemia show?

Answer 11

Examination may show vague abdominal tenderness disproportionate to the severity of the pain, an abdominal bruit and signs of generalised cardiovascular disease.

Question 12

How would you manage chronic mesenteric ischaemia ?

Answer 12

Asymptomatic patients are managed conservatively, with smoking cessation and antiplatelet therapy

Symptomatic chronic mesenteric ischaemia (CMI) is an indication for either open or endovascular revascularisation, as patients with untreated symptomatic CMI carry a five-year mortality rate that approaches 100%

Nutrition is important in pre-operative assessment, as patients are often malnourished at the time of diagnosis

Question 13

What is ischaemic colitis?

Answer 13

This is caused by a compromise of the blood circulation supplying the colon

Question 14

What causes ischaemic colitis?

Answer 14

1. Conditions causing arterial emboli
2. Conditions causing arterial thrombosis (atherosclerosis)
3. Decreases CO
4. Trauma
5. Strangulated hernia or volvulus.
6. Drugs
7. Disorders of coagulation:

Question 15

How do people with ischaemic colitis often present?

Answer 15

The diagnosis may be one of exclusion and should always be borne in mind in patients presenting with abdominal pain of indeterminate cause

Nonspecific symptoms of an ‘acute abdomen’, such as acute-onset abdominal pain

Marked tenderness may be found in the left iliac fossa but the presence of peritonitis suggests full thickness ischaemia, perforation, or alternative diagnosis.

Question 16

In younger people, what causes ischaemic colitis?

Answer 16

Taking the contraceptive pill, cocaine or methamfetamine abuse, the use of pseudoephedrine, sickle cell disease and inherited coagulopathies

Question 17

What do investigations for ischaemic colitis show?

Answer 17

Metabolic acidosis

Colonoscopy may show blue, swollen mucosa not showing contact bleeding and sparing the rectum.

Barium enema shows ‘thumb printing’ in the early phase that may last for several days

Question 18

How would you manage ischaemic colitis?

Answer 18

Broad-spectrum antibiotics are recommended.

If symptoms do not improve in 24-48 hours, repeat colonoscopy or imaging of the mesenteric vasculature with CT angiography is necessary to re-evaluate the severity and degree of the disease.

Increasing abdominal tenderness with guarding and rebound tenderness, fever, uncontrollable bleeding, and paralytic ileus indicate possible infarction of the colon (severe disease) and require urgent laparotomy and removal of the necrotic part of the colon.

Question 19

What arteries supply the colon?

Answer 19

Superior and inferior mesenteric arteries

Question 20

Where does the inferior mesenteric artery originate?

Answer 20

Arises from the left anterolateral aspect of the aorta

Question 21

Where does the superior mesenteric artery originate?

Answer 21

Arises from the anterior surface of the abdominal aorta

Question 22

Where is the splenic flexure?

Answer 22

Corner of descending colon and transvere colon (left side)

Question 23

Where is the hepatic flexure?

Answer 23

Corner of ascending colon and transvere colon (right side)

Question 24

What arteries supply the ascending colon?

Answer 24

The ascending colon receives arterial supply from two branches of the superior mesenteric artery; the ileocolic and right colic arteries

Question 25

What arteries supply the transverse colon?

Answer 25

The transverse colon is derived from both the midgut and hindgut, and so it is supplied by branches of the superior mesenteric artery and inferior mesenteric artery:

1. Right colic artery (from the superior mesenteric artery)
2. Middle colic artery (from the superior mesenteric artery)
3. Left colic artery (from the inferior mesenteric artery)

Question 26

What arteries supply the transverse colon?

Answer 26

The descending colon is supplied by a single branch of the inferior mesenteric artery; the left colic artery

Question 27

What arteries supply the sigmoid colon?

Answer 27

The sigmoid colon receives arterial supply via the sigmoid arteries (branches of the inferior mesenteric artery)

Question 28

Why is the marginal artery of Drummond clinically important?

Answer 28

The marginal artery (of Drummond) is a clinically important vessel that provides collateral supply to the colon – thereby maintaining arterial supply in the case of occlusion or stenosis of one of the major vessels

Question 29

What veins drain the sigmoid colon?

Answer 29

The sigmoid veins into the inferior mesenteric vein

Question 30

What veins drain the ascending colon?

Answer 30

The ileocolic and right colic veins, which empty into the superior mesenteric vein

Question 31

What veins drain the transverse colon?

Answer 31

The middle colic vein, which empties into the superior mesenteric vein

Question 32

What veins drain the descending colon?

Answer 32

The left colic vein, which drains into the inferior mesenteric vein

Question 33

What is a colonic stricture?

Answer 33

A band of scar tissue which forms as a result of the ischemic injury and narrows the lumen of the colon

Question 34

A 90 year old woman attends the Emergency Department with severe abdominal pain and diarrhoea. She has a history of angina. Investigations show infarction of the jejunum.

Which artery is most likely to be occluded?

A) Coeliac trunk
B) Inferior mesenteric
C) Left common iliac
D) Left gastric
E) Superior mesenteric

Answer 34

Superior mesenteric

Question 35

What arteries supply the duodenum?

Answer 35

The arterial supply of the duodenum is derived from two sources:

Proximal to the major duodenal papilla – supplied by the gastroduodenal artery (branch of the common hepatic artery from the coeliac trunk).

Distal to the major duodenal papilla – supplied by the inferior pancreaticoduodenal artery (branch of superior mesenteric artery).

Question 36

What arteries supply the jejnum and ileum?

Answer 36

The arterial supply to the jejunoileum is from the superior mesenteric artery

The superior mesenteric artery arises from the aorta at the level of the L1 vertebrae, immediately inferior to the coeliac trunk

Question 37

What seperates the small from the large intestine?

Answer 37

The ileocaecal valve

Its main function is to prevent the reflux of enteric fluid from the colon into the small intestine. It is also used as an landmark during colonoscopy, indicating that the limit of the colon has been reached and that a complete colonoscopy has been performed.

Question 38

What causes bowel obstructions?

Answer 38

Small bowel – adhesions and herniae

Large bowel – malignancy, diverticular disease, and volvulus

Question 39

What are features of bowel obstruction?

Answer 39

The cardinal features of bowel obstruction are:

Abdominal pain – colicky or cramping in nature (secondary to the bowel peristalsis)
Vomiting – occurring early in proximal obstructions and late in distal obstructions
Abdominal distension
Absolute constipation – occurring early in distal obstruction and late in proximal obstruction

Question 40

What test is key in bowel obstruction?

Answer 40

A CT scan with IV contrast of the abdomen and pelvis is the imaging modality of choice in suspected bowel obstruction and a shift in modern practice is moving towards CT scanning as the initial imaging used where possible.

Question 41

How would you manage bowel obstruction?

Answer 41

The definitive management of bowel obstruction is dependent on the aetiology and whether it has been complicated by bowel ischaemia, perforation, and/or peritonism.

Patients with closed loop bowel obstruction or evidence of ischaemia (pain worsened by movement, focal tenderness and pyrexia) require urgent surgery.

Question 42

What is closed loop bowel obstruction?

Answer 42

Closed loop obstruction is a specific type of bowel obstruction in which two points along the course of a bowel are obstructed, usually but not always with the transition points adjacent to each other at a single location. The closed loop refers to a segment of bowel without proximal or distal outlets for decompression.

Closed loop small bowel obstructions are usually secondary to adhesions, volvulus, or hernia

Question 43

How would you manage closed-loop bowel obstruction?

Answer 43

Risk of strangulation leads to high morbidity and mortality in closed loop bowel obstructions. Immediate surgical intervention is required.

Question 44

How does closed-loop bowel obstruction present?

Answer 44

Patients present with signs/symptoms of bowel obstruction, including crampy abdominal pain, vomiting, abdominal distension, and high pitched or absent bowel sounds.