Transcript Algorithm for Finding Sources of Obscure GI Bleeding

Finding Sources of Obscure
Lower GI Bleeding
William Kwan
Causes of Hematochezia
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COLONIC BLEEDING (95%)
Diverticular disease 30-40
Ischemia
5-10
Anorectal disease
5-15
Neoplasia
5-10
Infectious colitis
3-8
Postpolypectomy
3-7
IBD
3-4
Angiodysplasia
3
Radiation colitis/proctitis1-3
Other
1-5
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Unknown
10-25
SMALL BOWEL BLEEDING (5%)
Angiodysplasias
Erosions or ulcers (K, NSAIDs)
Crohn's disease
Radiation
Meckel's diverticulum
Neoplasia
Aortoenteric fistula
Causes of Hematochezia
 Diverticulosis
 Bleeding occurs in only 3-5%
 Left-sided source more common when diagnosed by
colonoscopy
 Right-sided source more common when diagnosed by
angiography
 Angiodysplasia
 Most common in cecum and ascending colon
 When in the small bowel, presents as iron deficiency
anemia and rarely as hematochezia
Causes of Hematochezia
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Hemorrhoids
Ischemic colitis
Neoplasms
NSAID-induced injury in terminal ileum and proximal
colon
 IBD
 10-15% of hematochezia caused by upper GI bleed
History
 NSAIDs & ASA strongly associated with lower GI
bleeding just as with upper GI bleeding
 Stercoral ulcers caused by severe constipation
 Recent polypectomy
 Hypovolemia preceding bleed suggests ischemic
colitis
Going Hunting
Going Hunting
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Bleeding source not found in 25%
KUB to look for perforation or obstruction
NG aspirate
Colonoscopy
 No agreement over whether prep is needed because of
increased risk of perforation with unpreped colon
 Radionuclide imaging
 Can detect slow bleeds at 0.1-0.5ml/min
 More sensitive but less specific than angiography
Going Hunting
 Angiography
 Requires bleeding of at least 1ml/min
 Very specific but not very sensitive
 May cause bowel infarction, renal failure
 Small bowel evaluation
 Push enteroscopy can allow evaluation of the first 60cm of
jejunum
 Video capsule to evaluate the remainder
 Meckel scan
Strategy with Lower GI
bleeding
 If persistently unstable and major bleeding, proceed
to surgery
 If colonic source, subtotal colectomy with ileorectal
anastomosis
 If small bowel source, resection
 If no identified source, intraoperative enteroscopy followed
by resection
 If stable and major bleeding
 Tagged red cell scan
 If positive, follow with angiography
 If negative, capsule endoscopy, enteroclysis, enteroscopy
Strategy with Lower GI
bleeding
 If stable and minor bleeding
 Colonoscopy
 If negative, capsule endoscopy, enteroclysis, enteroscopy
 If all studies negative
 Colonoscopy if rebleeding
Don’t Forget
 In addition to basic labs (CBC, Chemistries, Coags),
obtaining type and cross
 Two large bore peripheral IV’s
 Rectal exam as up to 40% of rectal cancers can be
detected this way
References
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Bounds, BC and PB Kelsey. Lower Gastrointestinal Bleeding. Gastrointestinal Endoscopy
Clinics of North America. 2007: 17, 273-88.
Townsend: Sabiston Textbook of Surgery. 18th ed.