Intestinal Ischeamia

Question 1

Define intestinal ischaemia

Answer 1

Obstruction of a mesenteric vessel (e.g. by a thrombus or embolus), leading to bowel ischaemia and necrosis.

There are three main types:
• Acute mesenteric ischaemia
• Chronic mesenteric ischaemia aka intestinal angina
• Chronic colonic ischaemia aka Ischaemic colitis

Question 2

What are the causes/risk factors of intestinal ischaemia?

Answer 2

*almost always involves the small bowel

• Arterial thrombosis (35%)
• Embolism (35%)
(These both will affect the SMA – superior mesenteric artery )
• Mesenteric vein thrombosis (5%): Occurs mainly in younger patients with hypercoagulable states. It tends to affect the small bowel
• Non-occlusive (20%): Poor cardiac output or renal failure leads to low perfusion
• Strangulation: Hernias and Volvulus
• Vasculitis
• Trauma

Risk factors:
Emboli:
• AF (known AF with sudden abdominal pain may indicate mesenteric ischaemia).
• Endocarditis ( can throw emboli)

Arterial Thrombosis: 
• Smoking 
• Hypertension 
• Obesity and low physical activity 
• Diabetes Mellitus 
• Dyslipidaemia 
• hypercholesteraemia 

Venous Thrombosis: 
• OCP 
• Thormbophilic disorders 
• Portal Hypertension 
• Splenectomy 
• thrombophlebitis

Question 3

What are the symptoms of intestinal ischaemia?

Answer 3

Classical Clinical Triad:
• Abdominal pain: Acute onset, severe and constant. Often found centrally or in the RIF.
• No or minimal abdominal signs (other than tenderness) on examination.
• Rapid hypovolaemia leading to shock.

• Fever, vomiting, nausea
• Constant or colicky abdominal pain.
• Rectal bleeding
• History of cardiovascular disease and liver disease *History of chronic mesenteric arterial insufficiency
• weight loss
• abdominal pain after eating (bowel claudication) – post prandial pain

Question 4

What are the signs of intestinal ischaemia?

Answer 4

• Diffuse abdominal tenderness and distension
• Hernia (if the cause is strangulation)
• Absent bowel sounds.
• Tender palpable mass
• Disproportionate cardiovascular collapse
• Fever and tachycardia
• Upper abdominal bruit

Question 5

What investigations are carried out for intestinal ischaemia?

Answer 5

• FBC - elevated WBC count, possible anaemia
• U&E’s - dehydration; Elevated urea or creatinine
• LFTs - could be altered in individuals with an underlying disorder leading to thrombosis
• Clotting Screen - prolonged INR, PTT, and PT
• Cross-match - before surgery
• ABG - actic acidosis
• AXR - may show thickening of small bowel folds and gas appearing within the bowel wall (late signs)
• Mesenteric Arteriography -allows localisation, a measure of the extent of involvement and a trial of intervention