definition
hypo perfusion of the gut due to occlusion, thrombosis or vasospasm
how does extent of clinical consequence be determined?
number of vessels affected
collateral potential
duration of insult
therefore timely diagnosis and treatment essential
4 main causes of acute mesenteric ischemia
- arterial embolism - typically mural
- aterial thrombus - mainly atherosclerosis
- venous thrombosis
- NOMI -
rare cases may be due to dissection, aneurysm and vasculitides
blood supply to the bowel
coeliac axis - to the foregut distal to oesophagus and second part of duodenum
s. mesenteric artery - to midgut third part of duodenum to mid transverse colon
i. mesenteric artery - hindgut mid transverse colon to rectum
how does the gut react to change in perfusion
can compensate for 12 hrs when 75% lost but if pressures are less than 40mmHg it will become ishcemic
15 mins = changes to villi
3 hrs = mucosa sloughs off
6 hrs = trans mural necrosis
– sepsis, perforation and death
how can affects of arterial occlusion be mitigated
collaterals more common in thrombosis as more time to develop in stenotic disease
thrombotic is usually more proximal and extent of disease more severe
clinical presentation
- sudden onset abdominal pain ( disproportionate)
- centrally or epigastric that is first colicky and then constant
- NaV and diarrhoea with posible blood
- history of recent cardiac events
on examination
- acutely ill, tachycardic and hypotensive
- distended abdomen
- bowel sounds normal or absent
- peritonitis as late sign
30 day prognosis
mean 68%
factors associated with poor outcome
age
extensive bowel necrosis
peritonitis and bowel perforation
co-morbidities
** major m/m
epi of chronic mesenteric ischemia
2 of the visceral arteries would need to be affected
commoner in women
50-70
clinical presentation of CMI
post-prandial pain in periumblical region that resolves after
weight loss due to fear of food
NaV
thin patient with abdominal bruit as well as stigmata of generalised arterial disease
