Mesenteric ischaemia and ischaemic colitis

Question 1

What is acute mesenteric ischaemia?

Answer 1

Acute mesenteric ischaemia (AMI) is a syndrome caused by inadequate blood flow through the mesenteric vessels, resulting in ischaemia and eventual gangrene of the bowel wall

Generally effects small bowel

Question 2

Pathology/ aetiology of acute mesenteric ischaemia

Answer 2

May occur due to superior mesenteric artery embolism or thrombosis, mesenteric vein thrombosis or non occlusive disease.

Other causes:
Trauma, Vasculitis, Radiotherapy, Strangulation

Question 3

Clinical presentation of acute mesenteric ischaemia?

Answer 3

Classical triad:
Acute severe abdominal pain (pain is constant and central OR around iliac fossa)

Rapid hypovolaemia–> Shock

No abdominal signs

Question 4

Diagnostic tests and results for acute mesenteric ischaemia

Answer 4

Bloods: Raised Hb concentration due to plasma loss, WCC, raised plasma amylase

Persistant metabolic acidosis

Question 5

Severe complications of acute mesenteric ischaemia?

Answer 5

Septic peritonitis: progression of septic inflammatory response syndrome into multi organ response syndrome

Mediated by bacterial translocation across the dying gut wall

Question 6

Treatment for acute mesenteric ischaemia?

Answer 6

Fluid resuscitation
Abx- gentamicin + metronidazole
Heparin

Local thrombolysis via a catheter
Dead bowel is removed in surgery

Question 7

How does heparin work?

Fondaparinux?

Answer 7

Activates antithrombin which inactivates factor 10a and prevents thrombin formation. Preventing conversion of fibrinogen to fibrin (preventing clot formation)

Fondaparinux only inhibits factor 10a

Question 8

How does CHRONIC mesenteric ischaemia present?

Rarely with history of vascular disease

Answer 8

Triad:
Abdo pain (severe, colicky, post-prandial)
Weight loss
Upper abdo bruit

+ PR bleeding, malabsorption, vomitting, nausea

Question 9

What tests would u do for chronic mesenteric ischaemia?

Answer 9

CT angiography/ Contrast enhanced MR angiography

Doppler USS

Question 10

Treatment for chronic mesenteric ischaemia?

Answer 10

Surgery due to ongoing risk of infarction:

Percutaneous transluminal angioplasty and stent insertion
Or open revascularisation

Question 11

What is ischaemic colitis?

Answer 11

Chronic colonic ischaemia

Due to reduced blood flow in inferior mesenteric artery

Ranges from mild ischaemia to gangrenous colitis

Question 12

Presentation of ischaemic colitis?

Answer 12

Low left sided abdominal pain +- bloody diarrhoea

Question 13

Tests for ischaemic colitis?

Answer 13

Colonoscopy + biopsy= gold standard

Also CT

Barium enema will show thumb printing in bowel if there is a sub mucosal swelling

Question 14

Treatment for ischaemic colitis?

Answer 14

Conservative fluid replacement and antibiotics

Most recover but strictures are common

Question 15

Gangrenous ischaemic colitis presentation?

Answer 15

Peritonitis and hypovolaemic shock

Question 16

Gangrenous ischaemic colitis treatment?

Answer 16

Prompt resuscitation

Followed by surgical resection and stoma formation (colostomy bag)