Intestinal Ischaemia Flashcards
describe a typical presentation of acute intestinal obstruction?
sudden onset diffuse pain
shock signs and norm exam
gas less abdo on AXR(recent operations, trauma, coagulopathy etc)
BS may be absent
describe a typical presentation of chronic intestinal ischaemia?
intermittent gut claudication
post-prandial pain
PR bleeding
Weight loss
norm abdo exam
Define intestinal ischaemia?
obstruction of the mesenteric artery-> leads to bowel ischaemia and necrosis
AF with abdominal cramping ( and rectal blood loss)-> should point towards mesenteric ischaemia
what are the different mesenteric arteries and the organs that they supply?
what are the risk factors for intestinal ischaemia?
AF
structural heart defects-> increase risk of emboli to mesenteric vessels
Arterial Thrombosis: hypercholesterolaemia, hypertension, diabetes mellitus, smoking
Venous Thrombosis: portal hypertension, splenectomy, septic thrombophlebitis, OCP, thrombophilia
what are the causes of acute mesenteric ischaemia?
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)
what is the cause chronic mesenteric ischaemia?
due to low flow state with atheroma
-> LIkely to have a history of vascular disease
what is ischaemic colitis?
inflammation of 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
what is the area most affected
splenic flexure-> watershed between superior and inferior mesenteric territories
what is a watershed area?
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.
summarise the epidemiology of intestinal ischaemia?
uncommon
more common in elderly
what are the presenting symptoms of acute mesenteric ischaemia?
acute severe abdominal pain
no abdominal signs
rapid hypovolaemia-> shock
pain tends to be constant, central or around RIF
what are the presenting symptoms of chronic mesenteric ischaemia?
severe
colicky post prandial abdominal pain ( Gut claudication)
loss of weight ( eating hurts)
+/- upper abdominal bruit
+/- PR bleeding
what are the presenting symptoms of chronic colonic ischaemia?
lower left-sided abdominal pain +/- bloody diarrhoea
what are the general symptoms of intestinal ischaemia?
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
what are the signs of intestinal ischaemia on physical examination?
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
what are the appropriate investigations for intestinal ischaemia?
AXR
CT is the current first-line investigation of choice when acute ischaemia is suspected and should be obtained early
Bloods
ECG
Mesenteric Angiography- only if stable
CT/MR angiography
Sigmoidoscopy/ colonoscopy
what is shown on AXR in intestinal ischaemia?
thickening of small bowel folds and signs of obstruction
early on shows ‘gas less abdomen’ and thumbprinting
describe bloods in intestinal ischaemia?
ABG - lactic acidosis
FBC – low Hb due to plasma loss, high WCC
Serum lactate – acidosis, uraemia, elevated creatinine
U&Es
LFTs
Clotting
Cross-match
why is an ECG useful for investigating intestinal ischaemia?
cardiac cause e.g. AF, acute MI
what does the sigmoidoscopy/ colonoscopy show in intestinal ischaemia?
mucosal friability/ petechiae, submucosal erosions/haemorrhagic nodules/ ulcerations, submucosal oedema, necrosis, gangrene
what are the investigations for ischaemic colitis and what would you see?
COLONSCOPY AND BIOPSY= GOLD STANDARD
barium enema shows “thumb printing” of submucosal swelling
