Acute & chronic mesenteric ischemia & colonic ischemia

Question 1

Colonic Ischemia definition

Answer 1

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._

Question 2

Colonic ischemia presentation

Answer 2

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).

Question 3

How to diagnose colonic ischemia?

Answer 3

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

Question 4

Causes of colonic ischemia

Answer 4

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

Question 5

What is seen on colonoscopy with colonic ischemia

Answer 5

see pale mucosa with petechial bleeding, bluish hemorrhagic nodules and cyanotic mucosa with hemorrhage. Done without bowel prep or air insufflation to prevent perforation;

Question 6

Do we ever use MR angiography to diagnose colonic ischemia?

Answer 6

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.

Question 7

What is small bowel mesenteric ischemia

Answer 7

part of small bowel loses blood flow and results in abdominal pain and damage downstream to area.

Question 8

Presentation of small bowel mesenteric ischemia?

Answer 8

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.

Question 9

How to diagnose small bowel mesenteric ischemia?

Answer 9

MRA or angiography to look for thrombus

Question 10

acute vs chronic mesenteric ischemia presentations

Answer 10

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)

Question 11

RF for acute mesenteric ischemia vs chronic mesenteric ischemia

Answer 11

acute mesenteric ischemia:

advanced age >70 yrs

atherosclerosis,

a fib,

CHF,

hypercoaguable disorders

Chronic mesenteric ischemia: cigarette smoking and atherosclerosis

Question 12

Labs seen on acute mesenteric ischemia

Answer 12

leukocytosis, elevated serum lactate and amylase and phosphate levels and metabolic acidosis

Question 13

chronic mesenteric ischemia labs

Answer 13

No changes

Question 14

diagnosis of acute mesenteric ischemia vs chronic mesenteric ischemia

Answer 14

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

Question 15

Treatment of acute vs chronic mesenteric ischemia

Answer 15

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.

Question 16

Presentation of rapid onset periumbilical pain (often severe), pain out of proportion to physical exam findings

Answer 16

think acute mesenteric ischemia

Question 17

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

Answer 17

chronic mesenteric ischemia can develop sitophobia (fear of eating due to pain)

Question 18

late finding of acute mesenteric ischemia?

Answer 18

hematochezia is a late complicaiton

Question 19

risk factors for acute mesenteric ischemia

Answer 19

atherosclerosis (acute or chronic) embolic source (thrombus or vegetations) hypercoaguable disorders

Question 20

lab findings of acute mesenteric ischemia

Answer 20

leukocytosis elevated amylase and phosphate levels metabolic acidosis (elevated lactate)

Question 21

Diagnosis of acute mesenteric ischemia?

Answer 21

CT (preferred) or MR angiography mesenteric angiography if diagnosis is unclear

Question 22

in geriatric patient with fever, abdominal pain, epigastric tenderness and new or undiagnosed A fib should consider

Answer 22

acute mesenteric ischemia

Question 23

what causes acute mesenteric ischemia

Answer 23

oclusion of arterial flow to small bowel or mesentery

Question 24

post prandial pain, sitophobia and weight loss

Answer 24

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

Question 25

Difference between left sided and right sided colonic ischemia?

Answer 25

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.