Ischemic Bowel Disease Flashcards
what are the 4 major causes of acute mesenteric ischemia?
SMA embolism, SMA thrombosis, nonocclusive ischemia, and mesenteric venous thrombosis
Why is superior mesenteric artery commonly involved with ischemic bowel disease?
due to it’s angle off of the aorta
Causes mesenteric (arterial) vasoconstriction and venous dilation. Reduces portal venous pressure in patients bleeding from portal hypertension
vasopressin
Hallmark of mesenteric arterial embolism
Severe cramping abdominal pain, out of proportion of physical findings, poorly localized
Where are the common origins of mesenteric arterial emboli?
Thrombus from L atrium, L ventricle or cardiac valves
Is coagualopathy associated with mesenteric arterial thrombosis?
no, this is more common a culprit in venous thrombosis patients
What is the usual site of blockage for mesenteric arterial thrombosis?
SMA or celiac axis
Affects younger popn (48-60). Thrombosis of superior mesenteric vein or intestinal strangulation from hernia or volvulus
mesenteric venous thrombosis
What is different about the presentation of mesenteric venous thrombois compared to mesenteric arterial thrombosis?
longer symptom presentation-Pain diffuse and nonspecific initially, but later becomes constant
Major risk factor for mesenteric venous thrombosis
hypercoagulable states (75%)
What is the etiology of nonocclusive mesenteric ischemia?
Result of splanchnic hypoperfusion & vasoconstriction
What is a major risk factor for nonocclusive mesenteric ischemia?
atherosclerotic disease
Mortality associated with nonocclusive mesenteric ischemia
70%
Any patient with abdominal pain and metabolic acidosis has what condition until proven otherwise?
intestinal ischemia
Critically important lab for intestinal ischemia
elevated serum lactate
What might be present on a plain film in patients with mesenteric ischemia?
air fluid levels, dilated bowel loops, gasless abdomen
Gas cysts in the bowel wall. Suggestive of necrotizing enterocolitis
Pneumatosis intestinalis
Accumulation of gas in the portal vein and it’s branches. A variety of causes such as ischemic bowel, intra-abdominal sepsis
portal venous gas
First step in the evaluation of the acute abdomen
plain abdominal xrays
What is the preferred imaging study in the evaluation of the acute abdomen?
CT scan
What is necessary for evaluatio of the mucosal thickening of the bowel wall?
oral contrast
What can obscure the view of mesenteric vessel of a CT angiogram?
oral contrast
Good study for evaluation of suspected intestinal ischemia but don’t do if planning on percutaneous angiography too (excessive contrast with 2 studies)
CT angiography
Better at diagnosing venous occlusions
MR angiography
If diagnosis is fairly certain and need consideration for percutaneous treatment or for surgical planning. Can’t be used for venous occlusions
mesenteric percutaneous arteriography
Vasopressors that have less effect on mesentary
dobutamine, low dose dopamine, milrinone
What can be given at angiography directly to relieve mesentaric vasoconstriction?
papaverine
Gold standard diagnostic study for acute arterial ischemia
Mesenteric Angiography
Treatment includes : Papaverine infusion during angiography. Reverse underlying conditions. Repeat angiography can be done in 24 hrs. Surgical exploration reserved for patients with peritoneal signs
Nonocclusive mesenteric ischemia
Intestinal angina. Episodic or constant intestinal hypoperfusion. Secondary to atherosclerosis. Strongly associated with meals
Chronic mesenteric ischemia
