Evaluation and Management of Lower GI Bleeding in Adults

Initial Assessment and Risk Stratification

Patients presenting with lower GI bleeding should be stratified as unstable or stable, with stable bleeds further categorized as major or minor using risk assessment tools like the Oakland score, which can identify patients suitable for outpatient management (score ≤8) versus those requiring hospital admission (score >8) 1
Patients can be categorized into four groups: minor bleeding that resolves with conservative therapy, chronic intermittent bleeding, severe life-threatening bleeding with periods of stability, or continual active bleeding 2

Resuscitation should occur concurrently with the initial evaluation, including fluid resuscitation and blood transfusion if necessary for hemodynamic instability 2
Coagulopathy or thrombocytopenia should be corrected with fresh frozen plasma or platelets, respectively 3

For patients with severe hematochezia and hypovolemia, an upper GI source should be considered, as it accounts for 10-15% of such cases 4
Upper endoscopy should be performed early in patients with risk factors for peptic ulcer, portal hypertension, or angiodysplasia 4

Colonoscopy is the diagnostic procedure of choice for acute lower GI bleeding with a diagnostic accuracy of 72-86% 4
Urgent colonoscopy after rapid bowel cleansing is feasible and useful in patients with severe hematochezia 4

Plain abdominal radiography should be performed prior to colonoscopy if bowel perforation or obstruction is suspected 5
Multidetector CT has an evolving role in localizing acute lower GI bleeding with an accuracy rate of 54-79% 5

Radionuclide imaging detects active bleeding at rates of 0.1-0.5 mL/min and is more sensitive than angiography but less specific than endoscopic or angiographic study 6
[99Tcm] pertechnetate-labeled red blood cell scanning is preferred for evaluation of lower GI bleeding which may be episodic 6
A positive red blood cell scan should be followed by urgent angiography within 1 hour 6

Assess hemodynamic status and initiate resuscitation as needed, and calculate shock index and Oakland score for risk stratification 1, 2
For hemodynamically stable patients, perform colonoscopy as the first-line diagnostic procedure, and consider upper endoscopy if upper GI source is suspected 2, 4
For hemodynamically unstable patients, consider urgent angiography or surgery for continual active bleeding 2
If bleeding source not identified, consider radionuclide imaging followed by angiography, and evaluate small bowel with enteroscopy or video capsule endoscopy 2, 6

Failure to consider an upper GI source in patients with severe hematochezia can lead to delayed diagnosis and treatment 4
Delayed colonoscopy may reduce diagnostic yield, particularly for identifying stigmata of recent hemorrhage 4
Overreliance on radionuclide imaging without confirmatory tests (colonoscopy, angiography) before surgery can lead to incorrect localization 6