Key Points
- Resuscitate first; use restrictive transfusion thresholds (e.g., Hb ~7 g/dL in stable, higher if coronary ischemia).
- CT angiography in brisk bleeding; colonoscopy within 24 h after prep in stabilized patients.
- Reverse/co-manage antithrombotics based on risk; avoid empiric octreotide/PPI unless upper source suspected.
Algorithm
- ABCs; large-bore IVs; labs including type & cross; resuscitate.
- Risk stratify; if ongoing hemodynamic instability → CT angiography ± IR embolization; otherwise prep and colonoscopy within 24 h.
- Reverse anticoagulation/antiplatelets selectively; identify and treat source (diverticular bleed, angioectasia, post-polypectomy).
Clinical Synopsis & Reasoning
For Lower Gi Bleed Initial, frame the differential by acuity and pathophysiology, then align diagnostics to the leading hypotheses. Prioritize stabilization while obtaining high‑yield studies such as CBC/Coags/Type & Cross (Bleeding assessment/prep), CT Angiography (Localize active bleeding), Colonoscopy (prepped) (Diagnostic/therapeutic). Incorporate bedside imaging and targeted labs to define severity and identify complications; synthesize results with clinical trajectory to refine the working diagnosis and disposition needs.
Treatment Strategy & Disposition
Initiate disease‑directed therapy alongside supportive care, titrating to objective response. Pharmacologic options commonly include Reversal agents (PCC/Vit K/idarucizumab/andexanet), No routine octreotide/PPI. Use validated frameworks (e.g., Common Etiologies) to guide escalation and site of care. Address precipitating factors, de‑escalate empiric therapies with data, and arrange follow‑up for monitoring and risk‑factor modification; admit patients with instability, high risk of deterioration, or needs for close monitoring.
Epidemiology / Risk Factors
- Older age, diverticulosis, angioectasias, antithrombotics
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| CBC/Coags/Type & Cross | Bleeding assessment/prep | Low Hb; coagulopathy | Trend |
| CT Angiography | Localize active bleeding | Contrast extravasation | Best in brisk bleed |
| Colonoscopy (prepped) | Diagnostic/therapeutic | Source identified/treated | Within 24 h after stabilization |
Common Etiologies
| Cause | Notes |
|---|---|
| Diverticular bleed | Often self-limited; can be brisk |
| Angiodysplasia | May need endoscopic ablation |
| Ischemic colitis | Supportive care; consider CTA if concern |
Pharmacology
| Medication | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| PPI (IV) | H+/K+ ATPase inhibition | Hours | Non-variceal UGIB | Infection risk long-term; ED use |
| Packed RBC | O₂-carrying capacity | Immediate | Transfuse to Hgb threshold | Transfusion reactions; ED use |
| Octreotide (variceal) | Splanchnic vasoconstriction | Minutes | Acute variceal bleed | Abdominal cramps; ED use |
| Balanced crystalloids | Plasma volume expansion | Immediate | Resuscitation | Fluid overload; ED use |
| Ceftriaxone (cirrhosis) | Cephalosporin | Hours | SBP prophylaxis in variceal bleed | Allergy; ED use |
Prognosis / Complications
- Most stop spontaneously; rebleeding risk depends on etiology and comorbidity
Patient Education / Counseling
- Medication review; colon follow-up as indicated; return precautions
Notes
Restrictive transfusion thresholds similar to UGIB. Coordinate antiplatelet/anticoagulant restart with cardiology when applicable.