Ch. 19 BRBPR

Question 1

What is the most common cause of lower GI bleed?

Answer 1

Diverticulosis

Question 2

Most common causes of LGIB?

Answer 2

H-DRAIN

• Hemorrhoids
  
  • Etiology: Bleeding from the hemorrhoidal venous plexus within anus
  • Risk factors: pregnancy, constipation, straining
  • Px: Painless BRBPR with straining at bowel movement
• Diverticular bleeds
  
  • Etiology: Arterial bleed from vasa recta at base of diverticula (90% of diverticula in sigmoid colon, but 60% of bleeds from R colon)
  • Risk factors: Advanced age, lack of fiber, obesity
  • Px: Painless BRBPR (hematochezia) in absence of stool
• Radiation colitis
  
  • Etiology: Direct mucosal damage from radiation exposure resulting in arteriolitis
  • Risk factors: Hx of pelvic radiation
  • Px: Bloody diarrhea, tenesmus (feeling of incomplete defecation)
• Angiodysplasia
  
  • Etiology: Aberrant blood vessels in GI tract; venous in origin
  • Risk factors: Advanced age, VWD, CKD, aortic stenosis
  • Px: painless, often presents with IDA
• Infectious/ischemic/IBD
• Neoplasms/polyps
  
  • Etiology: Colorectal adenocarcinoma may erode or ulcerate

Question 3

Why is age an important factor in a patient with a LGIB?

Answer 3

Acute LGIB in patients > 50 more likely to be diverticulosis, angiodysplasia, or malignancy

In younger patients, most common causes:

infectious, hemorrhoids, anal fissues, IBD

Question 4

Why are the onset and duration of bleeding important?

Answer 4

Diverticular bleeding = arterial (as a result, tends to present acutely with relatively large amounts of blood)

Angiodysplasia and cancer = chronic (more likely to present only with anemia / dark stools)

Question 5

What medicines should be looked for causally with a lower GI bleed? (3)

Answer 5

Coumadin, aspirin, Plavix

Question 6

_____ colonic diverticula are more likely to bleed while ______ colonic diverticula are more likely to get infected.

Answer 6

R, L

Question 7

Why is a hx of pelvic radiation on prior aortic surgery important?

Answer 7

Radiation can cause damage to rectal mucosa –> radiation proctitis

Aortic surgery rarely results in erosion of the aortic graft into duodenum, leading to aortoduodenal fistula

Question 8

Why should one inquire about alcohol hx and look for stigmata of liver cirrhosis?

Answer 8

Liver disease –> coagulopathy and portal HTN

Although portal HTN most commonly causes esophageal varices and UGI, varices can also form in rectal veins of lower GI tract due to their systemic and mesenteric connections

Question 9

What is the implication of abdominal tenderness on physical exam?

Answer 9

Highly suggestive of colitis such as from IBD, ischemic colitis, infectious diarrhea

Abdominal tenderness is unusual w/ bleeding from diverticulosis and angiodysplasia

Question 10

How does Ischemic Colitis classically present?

Cause?

Answer 10

L-sided abdominal pain + bloody diarrhea in elderly pts w/ low-flow states (severe dehydration, HF, shock, and trauma)

Cause?
decreased blood flow to colon (particularly in watershed areas)… not transmural so most pts will recover after correction of their “low-flow” state

Question 11

What is the natural hx of diverticular bleed?

Answer 11

75% stop bleeding spontaneously. Each episode of diverticular bleed increases the risk of a future bleed.

Question 12

*** Significant GI bleeding from a diverticulum is from diverticu______. Diverticul______ is NOT associated with bleeding. ****

Answer 12

Diverticulosis / Diverticulitis

Question 13

What is angiodysplasia? What are the risk factors?

Answer 13

Focal submucosal areas of thin, weak, and dilated vessels in the GI tract, most commonly in cecum and R colon in >60 y/o.

Incidence inc. with age, likely due to degeneration of vascular walls

*** unlike diverticular bleeds (arterial in origin), these are venous and therefore, bleed less ***

Ass: VWD, aortic stenosis, CKD

Question 14

Ischemic colitis vs. acute mesenteric ischemia

Pathophysiology

Natural Hx

Most commonly affected territories

Layers of bowel affected

Dx

Answer 14

Question 15

What is the initial treatment for lower GI bleed?

Answer 15

• IVFs:
  
  • Lactated Ringer’s
  • pRBC as needed
  • IV x 2
• Foley to follow urine output
• D/C aspirin
• NGT to r/o upper GI bleed!*

Question 16

1. What test is performed to localize bleeding if there is too much active bleeding to see the source with a colonoscope?
2. What is more sensitive for a slow, intermittent amount of blood loss: A-gram or tagged RBC study?
3. What is the treatment if bleeding site is KNOWN and massive or recurrent lower GI bleeding continues?
4. What % of cases spontaneously stop bleeding?
5. What is the therapeutic advantage of doing a colonoscopy?
6. What is the therapeutic advantage of doing an A-gram?

Answer 16

1. A-gram (mesenteric angiography)
2. Radiolabeled RBC scan is more sensitive for blood loss at a rate of >0.5 mL/min or intermittent blood loss b/c it has a longer 1/2 life
3. Segmental resection of the bowel
4. 80%
5. Options of injecting substance (epinephrine) or coagulating vessels = advantage with C-scope to control bleeding
6. Ability to inject vasopressin and/or embolization, with at least temporary control of bleeding in >85%

Question 17

A 72 y/o man s/p CABG 5 years ago presents with hematochezia, abdominal pain, and fevers. Colonoscopy reveals patches of dusky-appearing mucosa at the splenic flexure without active bleeding. What is the most appropriate mgmt of this pt?

Answer 17

Expectant mgmt

Ischemic colitis presents as hematochezia, fever, and abdominal pain. Unlike AMI, which affects the small intestine, and requires emergent intervention, IC rarely requires surgical intervention unless full-thickness necrosis, perforation, or refractory bleeding is present.

Expectant mgmt with IV fluids, bowel rest, and supportive care = treatment of choice