Intestinal Ischaemia Flashcards
what is the typical presentation of acute intestinal ischaemia?
sudden onset diffuse pain, shock signs and norm exam, gas less abdo on AXR(recent operations, trauma, coagulopathy etc), BS may be absent
what is the typical presentation of chronic intestinal ischaemia?
intermittent gut claudication, post-prandial pain, PR bleeding, Weight loss,norm abdo exam
Define intestinal ischaemia?
Obstruction of a mesenteric vessel leading to bowel ischaemia and necrosis
Note: AF with abdominal cramping pain (and rectal blood loss)should point towards mesenteric ischaemia
What are the three main types of intestinal ischaemia?
- Acute mesenteric ischaemia
- Chronic mesenteric ischaemia aka intestinal angina
- Chronic colonic ischaemia aka Ischaemic colitis
what are the risk factors for intestinal ischaemia?
AF
Endocarditis (can throw emboli)
Arterial Thrombosis: hypercholesterolaemia, hypertension, diabetes mellitus, smoking
Venous Thrombosis: portal hypertension, splenectomy, septic thrombophlebitis, OCP, thrombophilia
summarise the epidemiology of intestinal ischaemia?
UNCOMMON
More common in the 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 and signs 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 intestinal 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 symptomsof 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
ECG- demonstrate cardiac causes- AF, MI
Mesenteric Angiography- only if stable
CT/MR angiograph- replacing traditional angiography
Sigmoidoscopy/ colonoscopy – mucosal friability/ petechiae, submucosal erosions/haemorrhagic nodules/ ulcerations, submucosal oedema, necrosis, gangrene
For ischaemic colitis, colonoscopy and biopsy is gold-standard. Barium enemashows characteristic ‘thumb printing’ of submucosal swelling.
what does the AXR show in intestinal ischaemia?
thickening of small bowel foldsand signs of obstruction, early on shows ‘gas less abdomen’ and thumbprinting
describe the bloods for ischaemic colitis?
ABG - lactic acidosis
FBC – low Hb due to plasma loss, high WCC
Serum lactate – acidosis, uraemia, elevated creatinine
U&Es
LFTs
Clotting
Cross-match
what is the first line investigation when acute intestinal ischaemia
CT
what is the gold standard investigation for ischaemic colitis?
colonoscopy and biopsy
what does the barium enema show for ischaemic colitis?
characteristic ‘thumb printing’ of submucosal swelling
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 of chronic mesenteric ischaemia?
low flow state with atheroma
Likely to have history of vascular disease
what is the cause of ischaemic colitis?
Inflammation of the 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.
The splenic flexure,the watershed between superior and inferior mesenteric artery territories, is the most common area affected.
Occlusion by thrombus/embolus
Iatrogenic ligation
Hypovolaemia
Small vessel vasculitis in younger patients
Vasospasm e.g. cocaine
Hypercoagulable states
what is the common area affected in ischaemic colitis?
splenic flexure- watershed between superior and inferior mesenteric artery 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.
