Algorithm for Finding Sources of Obscure GI Bleeding

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					Finding Sources of Obscure
     Lower GI Bleeding
        William Kwan
      Causes of Hematochezia
   COLONIC BLEEDING (95%)           SMALL BOWEL BLEEDING (5%)
   Diverticular disease 30-40       Angiodysplasias
   Ischemia                 5-10    Erosions or ulcers (K, NSAIDs)
   Anorectal disease        5-15    Crohn's disease
   Neoplasia                5-10    Radiation
   Infectious colitis       3-8     Meckel's diverticulum
   Postpolypectomy          3-7     Neoplasia
   IBD                      3-4     Aortoenteric fistula
   Angiodysplasia           3
   Radiation colitis/proctitis1-3
   Other          1-5
   Unknown      10-25
    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
 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
   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
   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.

				
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posted:7/7/2011
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