Undifferentiated lower gastrointestinal bleeding

Background

• Loss of blood from the gastrointestinal 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^{[citation needed]}
• Cause of bleeding found in <50% of cases^{[citation needed]}
  • Diverticulosis cause majority, other conditions include colitis, polyps, colorectal cancer, hemorrhoids, anal fissures
• Hematochezia originates from briskly bleeding upper GI source in 10-15% of cases^{[citation needed]}

Medication Risk Factors

• Salicylates
• NSAIDs
• Warfarin

Clinical Features

Type of blood

• Hematochezia
  • Bright red or maroon-colored bleeding that comes from the rectum
  • Usually represents lower GI bleeding
  • May represent upper GI source if bleeding is brisk
    • Usually accompanied by hematemesis and hemodynamic instability
• Melena
  • Usually represents bleeding from upper GI source (see upper GI bleed)
  • May represent slow bleeding from lower GI source

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

Evaluation

Workup

• CBC
• Chemistries
  • BUN may be elevated if bleeding occurs from site high in GI tract
• Coags
• LFTs
• Type and screen
• Consider:
  • ECG (if concern for silent ischemia in patients likely to have CAD)
  • Fibrinogen
  • CTA
    • Requires brisk bleeding rate (0.5 cc/min) for detection^{[citation needed]}
  • Tagged red blood cell scan (not typically an emergency study)

Definitive studies

• Consider:
  • Anoscopy if source of bleeding cannot be identified on external exam
  • Proctoscopy (22cm from anal verge)
  • Sigmoidoscopy (60cm from anal verge)

False Positive Guaiac

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

Management

Categorize as stable versus unstable using shock index: <1 stable; >1 unstable or suspect active bleeding

• Unstable patients resuscitate, CT angiogram, if CTA does not identify source of bleeding, upper endoscopy if hemodynamic instability
• Consider transfusing pRBCs/platelets for unstable patients or with very low hemoglobin (<7). with cardiovascular disease use trigger of 8 and target of 10 hemoglobin.
• Emergent sigmoidoscopy/colonoscopy (next 24 hours)
• Surgery if endoscopy fails or not available
• Stable calculate risk score to determine disposition
  • Oakland score
  • Glasgow-Blatchford score

Major Bleed and Supratherapeutic INR

• Correct coagulopathy
  • Vitamin K 10mg IV (best bioavailability in critical patient)
  • PCC or FFP

Special situations

• Marathon runners - 16% will have hematochezia within 24-48 hrs of race and 85% will be guaiac positive
  • Non-actionable unless abdominal pain present

Disposition

Discharge

• Bleeding from hemorrhoids, anal fissures, or known IBD (hemodynamically stable)
• No gross blood on rectal exam (hemodynamically stable)
• Minor, self-terminating bleed with no other indication for admission (shock index >1; low risk score calculated)

Admission

• Melena
• Significant anemia
• Hemodynamic instability

See Also

Upper GI Bleeding