Intestinal ischaemia

Question 1

What is intestinal ischeamia?

Answer 1

Intestinal ischaemia = condition characterised by decreased blood flow to the intestines, causing ischemia

Can be chronic or acute
Can be from occlusive or non-occlusive aetiologies
Ischaemia leads to mucosal inflammation, oedema, necrosis and ulceration

Question 2

What is the aetiology of intestinal ischaemia?

Answer 2

Occlusive:
Arterial compromise -
Embolism ACUTE - LHS heart thrombus – atrial fibrillation
Interventional radiological procedures are the usual cause of atherosclerotic ruptures

Thrombosis ACUTE - Progression of atherosclerosis at the origin of the superior mesenteric artery

Vasculitis – younger patients, Caused by: RA, SLE, polyarteritis nodosa

External compression - Rare, Usually due to the median arcuate ligament of the diaphragm impinging onto the coeliac axis

Venous compromise -
Thrombosis (5%) ACUTE - DVT -> superior mesenteric vein, Usually associated with cirrhosis, portal hypertension or hyper-coagulable states

Non-occlusive:
Hypo-perfusion CHRONIC
Caused by: HF, dialysis, drugs (digitalis, oestrogen, vasopressors), recent surgery, infection, pancreatitis

Arteries: 
Coeliac – stomach, spleen, liver, gallbladder, duodenum
SMA – small intestine, right colon
IMA – transverse colon, left colon
Iliac - rectum

Question 3

What are the risk factors for intestinal ischaemia?

Answer 3

Atherosclerosis
Old age
Smoking
Hyper-coagulable
AF
MI
Structural heart defects
Vasculitis history

Question 4

What is the epidemiology of intestinal ischaemia?

Answer 4

Most common in elderly (60-80 yrs) - Particularly with co-existing morbidities

Equal gender distribution

Question 5

What are the symptoms of intestinal ischaemia?

Answer 5

Abdominal pain - Diffuse, Crampy, Post-prandial - gut claudication - producing food fear (sitophobia) - CHRONIC

Haematochezia (fresh blood in stool)/melaena - CHRONIC

Diarrhoea

Weight loss - CHRONIC

Nausea

LOC (shock)

Question 6

What are the signs of intestinal ischaemia?

Answer 6

Abdominal tenderness
Abdominal bruit
Fever
Shock -> hypotension, tachycardia
Local peritonism

Question 7

What are appropriate investigations for intestinal ischaemia?

Answer 7

Bloods	
FBC: leukocytosis, anaemia
Chemistry: acidosis, uraemia, elevated creatinine
Raised CRP
Clotting screen - hypercoagulability

Stool

ABG - Lactic acidosis

ECG - AF, arrhythmia, MI

CXR - Free air under diaphragm if perforation present

AXR - Gassless bowel, bowel dilation, bowel wall thickening, pneumatosis (gas in bowel wall from necrosis), thumb printing (submucosal oedema), Rigler’s sign (perforation), megacolon

Endoscopy - Mucosal sloughing, petechiae, erosions, ulcerations, sub-mucosal oedema

Other investigations
Mesenteric angiography - Proximal defect of mesenteric vessel

CT with contrast