Acute & chronic mesenteric ischemia & colonic ischemia Flashcards
Acute mesenteric ischemia, chronic mesenteric ischemia colonic ischemia
Colonic Ischemia definition
Condition where there’s ischemia and potentially necrosis of bowel; usually no clear precipitating event,
but has mild periumbilical left sided pain with abdominal tenderness
most common cause of colon ischemia is n_on occlusive low flow state in colonic microvasculature._
Colonic ischemia presentation
age>60
don’t appear severely ill has left sided crampy abdominal pain and tenderness, followed by bloody diarrhea
See EARLY hematochezia and bloody diarrhea in presentation (this is what separates it from acute mesenteric ischemia - which has bloody diarrhea as late sign).
How to diagnose colonic ischemia?
CT scan of abd/pel (prefer IV contrast) to rule out extensive bowel damage needing resection AND colonoscopy
MR angiography lacks the required resolution to i_dentify arterial occlusion and can overestimate severity of stenosis_
Doppler ultrasound of mesenteric veins - allows access to proximal ivsceral vessels but can’t see visualize distal vessels. best reserved with chronic mesenteric ischemia
Causes of colonic ischemia
related to hypovolumia
or decreased effective arterial blood volume leading to an abrupt and temporary decrease in blood flow to watershed areas (splenic flexure, rectosigmoid colon)
Other causes are:
dehydration,
strenous physical activity
medications
illicit drugs
thrombophilia
aortic or cardiac pypass
vasculitis
obstructing colon mass
What is seen on colonoscopy with colonic ischemia
see pale mucosa with petechial bleeding, bluish hemorrhagic nodules and cyanotic mucosa with hemorrhage. Done without bowel prep or air insufflation to prevent perforation;
Do we ever use MR angiography to diagnose colonic ischemia?
no
because it’s got low probability of showing a thrombus or embolus; lacks the resolution to see it and if it does, it overestimates the occlusion size.
What is small bowel mesenteric ischemia
part of small bowel loses blood flow and results in abdominal pain and damage downstream to area.
Presentation of small bowel mesenteric ischemia?
usually due to preceding event (a fib), variable age, severe pain without significant abd tenderness early in course pts are severely ill. Hematochezia is late complication.
How to diagnose small bowel mesenteric ischemia?
MRA or angiography to look for thrombus
acute vs chronic mesenteric ischemia presentations
Acute: rapid onset of perumblical pain (often severe) see hematochexia as late complication Chronic mesenteric ischemia: dull post prandial epigastric pain, food adversion and weight loss (seen in 80% of pts)
RF for acute mesenteric ischemia vs chronic mesenteric ischemia
acute mesenteric ischemia:
advanced age >70 yrs
atherosclerosis,
a fib,
CHF,
hypercoaguable disorders
Chronic mesenteric ischemia: cigarette smoking and atherosclerosis
Labs seen on acute mesenteric ischemia
leukocytosis, elevated serum lactate and amylase and phosphate levels and metabolic acidosis
chronic mesenteric ischemia labs
No changes
diagnosis of acute mesenteric ischemia vs chronic mesenteric ischemia
Acute: CT (preferred) or MR angiography. Mesenteric angiography if diagnosis is unclear at initial imaging Chronic: CT (preferred) or MR angiography. Duplex ultrasound and conventional angiography
Treatment of acute vs chronic mesenteric ischemia
acute: IVF resuscitation, broad spectrum abx, NG for decompression and surgery for bowel infarction or perforation; need CT angiography
Chronic: surgical reconstruction and percutaneous transluminal angioplasty +/- stent.
Presentation of rapid onset periumbilical pain (often severe), pain out of proportion to physical exam findings
think acute mesenteric ischemia
weight loss and p_ost prandial epigastric pain_ that radiates to the bad and worse in the 1st hour of eating.
Large fatty meals increase pain and pain resides in about 2 hrs
chronic mesenteric ischemia can develop sitophobia (fear of eating due to pain)
late finding of acute mesenteric ischemia?
hematochezia is a late complicaiton
risk factors for acute mesenteric ischemia
atherosclerosis (acute or chronic) embolic source (thrombus or vegetations) hypercoaguable disorders
lab findings of acute mesenteric ischemia
leukocytosis elevated amylase and phosphate levels metabolic acidosis (elevated lactate)
Diagnosis of acute mesenteric ischemia?
CT (preferred) or MR angiography mesenteric angiography if diagnosis is unclear
in geriatric patient with fever, abdominal pain, epigastric tenderness and new or undiagnosed A fib should consider
acute mesenteric ischemia
what causes acute mesenteric ischemia
oclusion of arterial flow to small bowel or mesentery
post prandial pain, sitophobia and weight loss
signs concerning for chronic mesenteric ischemia
Doppler ultrasound of mesenteric veins - allows access to proximal ivsceral vessels but can’t see visualize distal vessels. best reserved with chronic mesenteric ischemia
gold standard for diagnosis is selective catheter angiography
Difference between left sided and right sided colonic ischemia?
Two different types: Right sided vs. Left Sided.
most cases of colonic ischemia involve the left colon which is supplied by inferior messenteric ischemia - they tend to heal well with conservative therapy
isolated right colon ischemia - is harbinger of acute mesenteric ischemia caused by focal thrombus or embolus of superior mesenteric ischemia; artery supplies both small intestine and right colon
acute mesenteric ischemia with small bowel has mortality rates 60%
So people with isolated right colon ischemia require urgent non invasive imaging of mesenteric vasculature to assess extent of ischemia and nature of intervention. Get a CT angiography for diagnosing acute mesenteric ischemia.
