Undifferentiated lower gastrointestinal bleeding

Background

• Loss of blood from the GI tract distal to the ligament of Treitz
• Upper GI bleeds are most common source for blood detected in the lower GI system
• 80% of lower GI bleeding will resolve spontaneously
• Cause of bleeding found in <50% of cases

False Positive Guaiac

1. Red meat
2. Red jello
3. Fruit and vegetables
   • Melon, broccoli, radish, beets
4. Iron (causes GI bleed by irritation)

Diagnosis

History

• Type of blood
  • Hematochezia
    • Bright red or maroon-colored bleeding that comes from the rectum
    • Usually represents lower GI bleeding
    • May represent UGIB if bleeding is brisk
      • Usually accompanied by hematemesis and hemodynamic instability
  • Melena
    • Usually represents bleeding from upper GI source
    • May represent bleeding from lower GI source due to slow bleeding
• Medications
  • Salicylates, NSAIDs, warfarin

Physical Exam

1. Consider anoscopy if source of bleeding cannot be identified on external exam

DDX

1. [[Upper GI Bleeding}}
2. Diverticular disease
   1. Painless bleeding
   2. Up to 90% of episodes resolve spontaneously
   3. Can result in massive hemorrhage
3. Vascular ectasia
   1. Angiodysplasia, AVM
4. Inflammatory bowel disease
5. Colitis
   1. Infectious
   2. Ischemic
      1. 90% of cases occur in age >70yo
      2. Colon is predisposed to ischemia due to poor vascular ciculation, high bacterial count
      3. Causes: aneurysmal rupture, vasculitis, hypercoagulable, CV insult, IBS, slow motility
      4. Most cases resolve on own; 20% of cases requires surgical intervention
6. Mesenteric Ischemia
   1. Medical emergency that often leads to bowel necrosis
   2. Causes: thrombosis/embolism of SMA, mesenteric vein thrombosis, low arterial flow
   3. Associated w/ A fib, CHF, MI, age >60yo
   4. CT only 64% Sn, angiography is imaging study of choice
7. Meckel Diverticulum
8. Malignancy / polyps
9. Hemorrhoids
   1. Massive hemorrhage is unusual
10. Aortoenteric fisulta (after AAA repair)
    1. Low grade fever, abd pain, back pain, h/o graft, BRBPR
11. Foreign body
12. Rectal ulcer (HIV, Syphilis, STI)
13. Anal fissure

Workup

1. Labs
   1. CBC
      1. Chemistry
      2. BUN may be elevated if bleeding occurs from site high in GI tract
   2. Coags
   3. LFTs
   4. Type and screen
2. ECG (if concern for silent ischemia in pts likely to have CAD)
3. Imaging
   1. CTA
      1. Requires brisk bleeding rate (0.5 cc/min) for detectio
   2. Proctoscopy (22cm from anal verge)
   3. Sigmoidoscopy (60cm from anal verge)

Treatment

• IVF
• Major Bleed and Supratheraputic INR
  • Correct coagulopathy
    • Vitamin K 10 mg IV (best availability in critical pt)
    • FFP
  • Consider pRBCs/platelets for unstable and low H/H
• Consider NGT - high possibility for surgery to request
• Hematochezia unexpectedly originates from upper GI source 10-15% of cases
• Emergent Sigmoidoscopy/colonoscopy (next 24 hours)
• Surgery if endoscopy fails or not available

Disposition

• Discharge:
  • Bleeding from hemorrhoids, anal fissures, or known IBD (hemodynamically stable)
  • No gross blood on rectal exam (hemodynamically stable)

See Also

Upper GI Bleeding

Source

• Tintinalli