bowel ischaemia Flashcards
in broad terms what are the 3 types of bowel ischaemia
acute mesenteric ischaemia- superior mesenteric artery- often thrombus or embolism
chronic mesenteric ischaemia- triad of colic post prandial pain (severe), decreaced weight, upper abdominal bruit–> usually a diffuse atherosclerotic disease
chronic colonic ischaemia- inferior mesenteric artery low flow. ranges from mild to gangrenous.
physiology, S+S, acute mesenteric ischaemia
almost always the small bowel.
thrombus or embolism (35% each) most common causes. mesenteric vein thrombosis (5%) and non-occlusive (think hypotension) 20% also causes.
presents with acute sever abdo pain which is central/ RIF
, minimal/ no abdominal signs, rapid hypovolaemia + shock.
degree of illness is far out of proportion with clinical signs.
Ix, Rx, prognosis acute mesenteric ischaemia.
Ix: FBC- possibly inc HB due to plasma leak,
inc WCC, modestly raised plasma amylase.
persistant metabolic acidosis (high lactate)
abdo x-ray may be gasless
CT/MRI may show necrosis –> angio if doubt remains
Rx: treat the major compications if they occur- septic peritonitis (bact translocation accross gut wall), Systemic inflammatory response syndrome.
fluid resusitation, antibiotics, LMWH.
if angio done local thrombylisis can be done.
thrombectomy, baloon angioplasty,
IF surgical- necrotic bowel must be removed. can do embolectomy
or mesenteric bypass with graft. may need re-look in 24-48 hrs.
prognosis- not great for art and non occlusive (<40%)
what is the major co condition that you should link with acute mesenteric ischaemia
Atrial fibrilation- any abdo pain with AF should raise suspicion.
risk factors for chronic mesenteric ischaemia
female, older than 60, smoker, CVS disease, PAD,
other 5% that arent atherosclerotic - vasculitis, fibromuscular dysplasia, arteritis, malignancy, radiation.
invesigation and treatment of chronic mesenteric
CT angio + contrast enhanced MR angio
Rx: consider surgical intervention due to high risk of progress to acute
perc transluminal angioplasty + stent is becoming more popular. - less morbidity but higher reoccurance.
chronic colonic ischaemia
AKA ischaemic cholitis
inferior mesenteric artery low flow. mild to gangrene
Presents with lower left abdo pain +/- bloody diahroea
Ix: lower GI endoscopy is ‘gold standard’
manage with fluid, abx,
development of ischaemic strictures is common. Think about any vasoconsrictive drugs and stop if able.
if gangrenous more aggressive resection and stoma formation needed.
classification of NOMI or colonic ischaemia
mild: typical symptoms, no identifiable risk factor, no isolated right colonic lesion.
moderate: when they have up to 3 of the following- male, tacycardia, hypotension, blood urea >20, hb<12. WC > 15 amongs other things. abdo pain with rectal bleeding or colonoscopicly identified mucosal ulceration
Severe- more than 3 of the earlier signs or peritoneal signs, gangrene, pneumatosis on CT, isolated right colonic lesion.
generally mod- 3 symptoms, severe- more than that
what are the watershed zones and where are they
the splenic flexure (SMA and IMA) and the rectosigmoid junction (IMA, Sup rectal)
areas where ischaemia is most likely to happen as it is the meeting of two blood supplies.
