Intestinal Ischaemia

Question 1

what is the typical presentation of acute intestinal ischaemia?

Answer 1

sudden onset diffuse pain, shock signs and norm exam, gas less abdo on AXR(recent operations, trauma, coagulopathy etc), BS may be absent

Question 2

what is the typical presentation of chronic intestinal ischaemia?

Answer 2

intermittent gut claudication, post-prandial pain, PR bleeding, Weight loss,norm abdo exam

Question 3

Define intestinal ischaemia?

Answer 3

Obstruction of a mesenteric vessel leading to bowel ischaemia and necrosis

Note: AF with abdominal cramping pain (and rectal blood loss)should point towards mesenteric ischaemia

Question 4

What are the three main types of intestinal ischaemia?

Answer 4

• Acute mesenteric ischaemia
• Chronic mesenteric ischaemia aka intestinal angina
• Chronic colonic ischaemia aka Ischaemic colitis

Question 5

what are the risk factors for intestinal ischaemia?

Answer 5

AF

Endocarditis (can throw emboli)

Arterial Thrombosis: hypercholesterolaemia, hypertension, diabetes mellitus, smoking

Venous Thrombosis: portal hypertension, splenectomy, septic thrombophlebitis, OCP, thrombophilia

Question 6

summarise the epidemiology of intestinal ischaemia?

Answer 6

UNCOMMON

More common in the ELDERLY

Question 7

what are the presenting symptoms of acute mesenteric ischaemia?

Answer 7

acute severe abdominal pain + no abdominal signs + rapid hypovolaemia = shock

Pain tends to be constant, central or around RIF

Question 8

what are the presenting symptoms and signs of chronic mesenteric ischaemia?

Answer 8

severe, colicky post-prandial abdominal pain (gut claudication), loss of weight (eating hurts) +/- upper abdominal bruit +/- PR bleeding

Question 9

what are the presenting symptoms of intestinal ischaemia

Answer 9

severe, colicky post-prandial abdominal pain (gut claudication), loss of weight (eating hurts) +/- upper abdominal bruit +/- PR bleeding

Question 10

what are the presenting symptoms of chronic colonic ischaemia?

Answer 10

lower left-sided abdominal pain +/- bloody diarrhoea

Question 11

what are the general symptomsof intestinal ischaemia?

Answer 11

Fever

Severe acute colicky abdominal pain

Vomiting

Nausea

Bloody diarrhoea

History of chronic mesenteric artery insufficiency

• Gross weight loss
• Post-prandial abdominal pain

History of heart or liver disease

Question 12

what are the signs of intestinal ischaemia on physical examination?

Answer 12

Fever and tachycardia

Diffuse abdominal tenderness

Abdominal distension

Tender palpable mass (ischaemic bowel)

Bowel sounds may be absent

Disproportionate degree of cardiovascular collapse

Upper abdominal bruit

Question 13

what are the appropriate investigations for intestinal ischaemia?

Answer 13

AXR

CT is the current first-line investigation of choice when acute ischaemia is suspected and should be obtained early

ECG- demonstrate cardiac causes- AF, MI

Mesenteric Angiography- only if stable

CT/MR angiograph- replacing traditional angiography

Sigmoidoscopy/ colonoscopy – mucosal friability/ petechiae, submucosal erosions/haemorrhagic nodules/ ulcerations, submucosal oedema, necrosis, gangrene

For ischaemic colitis, colonoscopy and biopsy is gold-standard. Barium enemashows characteristic ‘thumb printing’ of submucosal swelling.

Question 14

what does the AXR show in intestinal ischaemia?

Answer 14

thickening of small bowel foldsand signs of obstruction, early on shows ‘gas less abdomen’ and thumbprinting

Question 15

describe the bloods for ischaemic colitis?

Answer 15

ABG - lactic acidosis

FBC – low Hb due to plasma loss, high WCC

Serum lactate – acidosis, uraemia, elevated creatinine

U&Es

LFTs

Clotting

Cross-match

Question 16

what is the first line investigation when acute intestinal ischaemia

Answer 16

CT

Question 17

what is the gold standard investigation for ischaemic colitis?

Answer 17

colonoscopy and biopsy

Question 18

what does the barium enema show for ischaemic colitis?

Answer 18

characteristic ‘thumb printing’ of submucosal swelling

Question 19

what are the causes of acute mesenteric ischaemia?

Answer 19

Almost always involves small bowel

Arterial thrombosis (35%) or embolism (35%)

Affects superior mesenteric artery

• Non-occlusive ischaemia

Occurs in low flow states, likely to have low CO

• Venous thrombosis (5%)

Affecting mesenteric vein; more common in younger patients with hypercoagulable states

Other: trauma, vasculitis, radiotherapy, strangulation (volvulus/hernia)

Question 20

what is the cause of chronic mesenteric ischaemia?

Answer 20

low flow state with atheroma

Likely to have history of vascular disease

Question 21

what is the cause of ischaemic colitis?

Answer 21

Inflammation of the colon caused by decreased colonic blood supply.

Usually follows low flow state in inferior mesenteric artery. Ischaemia leads to mucosal inflammation, oedema, necrosis and ulceration.

The splenic flexure,the watershed between superior and inferior mesenteric artery territories, is the most common area affected.

Occlusion by thrombus/embolus

Iatrogenic ligation

Hypovolaemia

Small vessel vasculitis in younger patients

Vasospasm e.g. cocaine

Hypercoagulable states

Question 22

what is the common area affected in ischaemic colitis?

Answer 22

splenic flexure- watershed between superior and inferior mesenteric artery territories

Question 23

what is a watershed area?

Answer 23

region that receives a dual blood supply from the most distal branches of two large arteries

If there is blockage of one of the arteries, these regions are spared due to dual supply.

But, when there is systemic hypoperfusion, these regions are particularly susceptible as they are supplied by most distal branches.