What is the pathophysiology of chronic mesenteric ischemia?
Ischemic bowel disease due to mesenteric atherosclerosis: hypo perfusion related to eating (increased demand during eating + decreased blood supply)
Symptoms of chronic mesenteric ischemia
What is the definitive diagnostic test for chronic mesenteric ischemia?
-Angiography
Definitive management for chronic mesenteric ischemia
-Revascularization (angioplasty with stenting or bypass
What is the MC cause of acute mesenteric ischemia?
-Acute arterial occlusion (embolism from A-fib)
What artery is MC occluded in an acute mesenteric ischemia?
-Superior mesenteric artery
Symptoms of acute mesenteric ischemia
What is the initial test to assess ischemia for acute mesenteric ischemia?
-CT angiography
However, to get a definitive diagnosis for acute mesenteric ischemia, what should be done?
-Conventional arteriography
Treatment for acute mesenteric ischemia
- Anticoagulation in patients with A-fib
Ischemic colitis is
decreased colonic perfusion, leading to inflammation
What is the MC etiology of ischemic colitis
-Transient systemic hypotension or atherosclerosis involving the superior and inferior mesenteric arteries
Ischemic colitis occurs MC at watershed areas (between 2 arteries with decreased collaterals) such as the _____ and _______
splenic flexure and rectosigmoid junction
Symptoms of ischemic colitis
What is the first imaging study that is done for ischemic colitis and what does it show?
CT of the abdomen: thumb printing (segmental bowel wall thickening)
What is the treatment for ischemic colitis?
- May need empiric broad spectrum ABX, but most resolves without therapy
What type of colon polyp is the MC non-neoplastic polyp?
Hyperplastic
Pseudopolyps/Inflammatory polyps are due to
Inflammatory bowel disease (UC, Crohn’s)
What type of colon polyp is the MC neoplastic polyp?
Adenomatous polyps
How long does it take an adenomatous polyp to become cancerous?
10-20 years
Which type of adenomatous polyp is associated with the least risk?
Tubular Adenoma (MC type and least risk)
Which type of adenomatous polyp has the highest risk of becoming cancerous?
Villous adenoma
Risk factors for colorectal cancer
Familial Adenomatous Polyposis is a genetic mutation of the _____ gene. Explain what happens with this condition
APC gene
Adenomas begin in childhood. Almost all develop cancer by 45 years old. Prophylactic colectomy is best for survival.