Lower GI bleeding
Distal to Treitz. Diverticular, angioectasia, colitis, neoplasm, post-polypectomy, hemorrhoids, ischemic colitis (left, painful, bloody).
Brittni Driscoll5 min6 questions1 trials
Distal to Treitz
Hematochezia — maroon or bright red, often with clots. Melena is rare (needs ~14 h in the gut). BUN/Cr is typically <20 when kidneys are normal ().
- ABC score for 30-day mortality. Oakland <8 may predict safe discharge ().
- CBC q2–12 h, CMP, coags, type and screen. Same restrictive transfusion as UGIB (Villanueva, ): Hb 7, or 8 if CAD (; ). Platelets >50k. Two large-bore IVs.
- ASA for primary prevention: stop and generally do not resume. ASA for secondary prevention: do not hold; if held, restart as soon as the bleed settles ().
Unstable vs stable pathway
Hemodynamically unstable
- index (HR/SBP) >1: CTA is the diagnostic test of choice ().
- Consult GI, IR, and surgery together.
- Exonerate UGIB with EGD (or CTA first if that is faster).
- IR embolization if too unstable for endoscopy — bowel ischemia and vascular injury are the prices.
- Subtotal colectomy if you cannot find or control the source.
Stable
- Colonoscopy is the diagnostic test of choice after a prep.
- Non-urgent inpatient colo for most admissions (strong rec; ).
- Skip colo if the bleed has stopped and a recent colo already showed diverticulosis ().
- No solids or red liquids for 8 h; use a full bowel-prep order set.
- CTA is low-yield once the bleed has quieted. Tagged-RBC scans are more sensitive but localize poorly — rarely first-line.
History points at the source
NEJM 2017;376:1054.
| Story | Think |
|---|---|
| Painless large-volume maroon blood, older adult | Diverticular (30–65%) until proven otherwise; angioectasia 5–10%; hemorrhoid 5–20% |
| Crampy pain + bloody diarrhea after hypotension | Ischemic colitis (watershed: splenic flexure / rectosigmoid). Supportive; antibiotics if severe; surgery if peritonitis. SMA embolism is a different (small-bowel) emergency |
| Weight loss | Neoplasm / polyp 2–15%, IBD 3–5% |
| Fever / diarrhea | IBD, infectious colitis, mesenteric ischemia |
| AS, ESRD, LVAD | Angioectasia; Heyde (AS + acquired vWD + right-colon angioectasias) |
| Recent polypectomy | Delayed post-polypectomy bleed (2–7%) — clip / cautery if ongoing |
| Constipation / NSAIDs / XRT / liver disease / AF / AAA repair / SCT | Stercoral ulcer, NSAID colopathy, radiation proctopathy, colorectal varices, acute mesenteric ischemia, aortoenteric fistula, GVHD |
Obscure bleed after EGD + colonoscopy (ACG: )
- ~75% small bowel, 25% missed UGIB/LGIB. Young: IBD, Meckel, polyposis, Dieulafoy, neoplasm. Any age: angioectasia, NSAID ulcers. Rare: varices, amyloid, HHT, Kaposi.
- Video capsule first-line unless known strictures (retention risk). Second-look EGD ± push enteroscopy for recurrent upper symptoms; second-look colo for recurrent hematochezia.
- CT enterography if capsule negative or stricture risk (IBD, XRT, prior small-bowel surgery). Balloon enteroscopy when therapy is needed after a positive capsule.
- Brisk: CTA if stable, then angio. Unstable: embolize, enteroscope, or operate.
- No source: iron repletion; consider octreotide or anti-angiogenic therapy; replace the aortic valve if Heyde is bleeding.