Intestinal Ischaemia Flashcards
What is intestinal ischaemia?
Obstruction of a mesenteric vessel leading to bowel ischaemia + necrosis
What are the 3 main types of intestinal ischaemia?
Acute mesenteric ischaemia
Chronic mesenteric ischaemia (intestinal angina)
Ischaemic colitis
Describe the epidemiology of mesenteric ischaemia
UNCOMMON
More common in the ELDERLY
Chronic: F > M
RF: HTN, hyperlipidaemia, smoking, diabetes, AF
List 3 features of presentation of acute mesenteric ischaemia
Acute severe, constant abdo pain, disproportionate to findings
N+V
Diarrhoea (+blood later) s + rapid hypovolaemia
List 5 features of presentation of chronic mesenteric ischaemia
Dull, colicky post-prandial abdo pain (gut claudication)
Weight loss (eating hurts + malabsorption)
Upper abdo bruit
Bloating, nausea
Concurrent vascular co-morbidities
Give 3 symptoms of ischaemic colitis
Sudden onset, crampy abdo pain (often LIF)
N+V
Bloody diarrhoea
What is diagnosis of intestinal ischaemia based on?
Clinical suspicion or after laparotomy
What investigations may be performed in acute mesenteric ischaemia?
High lactate, high LDH, high creatine kinase
Leukocytosis
Metabolic acidosis
CT angiography confirms dx
What investigations may be performed in chronic mesenteric ischaemia?
Bloods may show malabsorption/ dehydration
CT angiography confirms dx
What is a watershed area? What occurs in systemic hypo perfusion?
A region that receives a dual blood supply from the most distal branches of 2 large arteries.
Systemic hypoperfusion: susceptible to ischaemia as supplied by most distal branches.
What is the firstline investigation for suspected acute intestinal ischaemia?
CT
Should be obtained early.
What 3 features may be seen on colonoscopy in ischaemic colitis?
Submucosal oedema
Ulceration
Gangrene
What is Acute mesenteric ischemia?
Acute inadequate blood flow to the small intestine that can result in bowel infarction
What is Chronic mesenteric ischaemia?
Reduced blood supply to the small bowel which gradually deteriorates over time as a result of atherosclerosis
Describe the pathophysiology of ischaemic colitis
Intestinal blood flow of SMA +/- IMA is suddenly compromised
Intestinal hypoxia + wall damage
Mucosal inflammation +/- bleeding
May progress to infarction + necrosis (gangrenous type)
Disruption of mucosal barrier + perforation
Release of bacteria, toxins, vasoactive substances
Life-threatening sepsis
Which areas are at high risk of colonic ischaemia?
Watershed areas:
Splenic flexure
Rectosigmoid junction
Describe the epidemiology of ischaemic colitis
Most common form of intestinal ischemia
Mainly occurs > 60 years
80–85%= mild, nongangrenous form
Which conditions may acute arterial emboli arise from causing Acute mesenteric ischemia?
AF
MI
Valvular heart disease
Endocarditis
Describe the pathophysiology of Acute mesenteric ischemia
Sudden interruption of blood flow to small bowel
Intestinal hypoxia
Hemorrhagic infarction + necrosis
Disruption of mucosal barrier + perforation
Release of bacteria, toxins, vasoactive substances
Life-threatening sepsis
List 6 causes of reduced flow through the IMA in ischaemic colitis
Occlusion by thrombus/embolus Iatrogenic ligation Hypovolaemia Small vessel vasculitis in younger patients Vasospasm e.g. cocaine Hypercoagulable states
What investigations may be performed in ischaemic colitis?
If severe; High lactate, high LDH, high creatine kinase, Leukocytosis, Metabolic acidosis
AXR: Bowel wall thickening
CT: wall thickening + gas in wall, thumbprinting
Colonoscopy: confirms dx + assesses severity
What is ischaemic colitis?
Hypoperfusion of the LARGE bowel
Mostly transient + self-limiting (nongangrenous), but can lead to severe acute ischemia with bowel infarction (gangrenous)
