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

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

Differential Diagnosis

Undifferentiated lower gastrointestinal bleeding

• Upper GI Bleeding
• Diverticular disease
  • Diverticulosis
  • Diverticulitis
• Vascular ectasia / angiodysplasia
• Inflammatory bowel disease
• Infectious colitis
• Mesenteric Ischemia / ischemic colitis
• Meckel's diverticulum
• Colorectal cancer / polyps
• Hemorrhoids
  • Internal hemorrhoid
  • External hemorrhoid
• Aortoenteric fistula
  • Nearly 100% mortality if untreated
  • Consider in patients with gastrointestinal bleeding and known abdominal aortic aneurysms or aortic grafts
• Rectal foreign body
• Rectal ulcer (HIV, Syphilis, STI)
• 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