In an elderly patient with acute bright‑red rectal bleeding, known colonic polyps, hypertension, pallor, tachycardia (heart rate 110) and blood pressure 160/90, what is the most appropriate immediate management: urgent colonoscopy, contrast‑enhanced CT angiography, or intravenous crystalloid fluids and packed red blood cell transfusion?

Immediate Management: Intravenous Fluids and Blood Products First

In this elderly patient with acute bright‑red rectal bleeding, known colonic polyps, pallor, tachycardia (HR 110), and blood pressure 160/90, the most appropriate immediate management is aggressive intravenous crystalloid resuscitation and packed red blood cell transfusion to restore hemodynamic stability before any diagnostic procedure. 1, 2

Hemodynamic Assessment and Resuscitation Priority

• Calculate the shock index (heart rate ÷ systolic blood pressure): 110 ÷ 160 = 0.69, which is numerically below the threshold of 1.0 that defines frank instability. 1, 2

• However, the combination of tachycardia (HR 110), pallor, and ongoing bright‑red rectal bleeding indicates significant active blood loss requiring immediate aggressive resuscitation, even though the shock index is <1. 1, 2

• Resuscitation must be performed concurrently with initial clinical evaluation and must always precede any diagnostic procedure such as colonoscopy or CT angiography. 2

Initial Resuscitation Protocol

• Place two large‑bore intravenous catheters immediately and begin aggressive crystalloid infusion (normal saline or Ringer's lactate) to normalize blood pressure and heart rate. 2

• Transfuse packed red blood cells when hemoglobin falls below 100 g/L in the setting of acute bleeding; mortality rises with increasing severity of anemia. 2

• After initial stabilization, apply a restrictive transfusion strategy: maintain hemoglobin >70 g/L in patients without cardiovascular disease, but target >80 g/L (aiming for 100 g/L) in patients with hypertension or other cardiovascular risk factors—this patient has documented hypertension, so the higher threshold applies. 1, 2

• Correct coagulopathy promptly: transfuse fresh‑frozen plasma when INR >1.5 and platelets when platelet count <50 × 10⁹/L. 1, 2

Why Not Urgent Colonoscopy or CT Angiography First?

Colonoscopy is Contraindicated Until Stabilization

• Colonoscopy is explicitly contraindicated until adequate hemodynamic resuscitation has been achieved. 2

• Adequate bowel preparation requires 4–6 L of polyethylene glycol administered over 3–4 hours, which is not feasible in an actively bleeding, unstable patient. 1, 2

• Performing colonoscopy within 24 hours of presentation does not reduce re‑bleeding rates, mortality, or length of hospital stay compared with elective colonoscopy after stabilization. 1, 2

• Endoscopic evaluation must never be undertaken before achieving stable blood pressure and central venous pressure. 2

CT Angiography is Reserved for Persistent Instability After Resuscitation

• CT angiography (CTA) should be performed immediately as the first diagnostic test only if the patient remains hemodynamically unstable (shock index >1) after initial resuscitation or if active bleeding is suspected. 1, 2

• CTA is preferred over colonoscopy in unstable patients because it can localize bleeding in the upper GI tract or small bowel, is widely available, can be rapidly accessed, and has no requirement for bowel preparation. 1

• In this case, the patient's shock index is 0.69 (below the threshold of 1.0), so the immediate priority is resuscitation rather than imaging. 1, 2

Subsequent Management Algorithm After Resuscitation

If Patient Stabilizes (Shock Index Remains ≤1)

• Calculate the Oakland score (age ≥70 = 2 points; male = 1 point; blood on DRE = 1 point; HR ≥110 = 3 points; SBP ≥160 = 0 points; hemoglobin unknown but likely low given pallor = estimated 8–13 points). 1, 2

• If Oakland score >8 points, admit for inpatient colonoscopy on the next available list after completing bowel preparation. 1, 2

• Colonoscopy should be scheduled on the next available inpatient list; urgent colonoscopy within 24 hours does not confer benefit in rebleeding, mortality, or length of stay. 1, 2

If Patient Remains Unstable After Resuscitation (Shock Index >1)

• Perform CT angiography immediately as the first diagnostic test; it has a sensitivity of ≈94% and can detect bleeding as low as 0.3 mL/min. 1, 2

• When CT angiography identifies a bleeding source, catheter‑directed angiography with embolization should be performed within 60 minutes; technical success rates range from 40% to 100%. 1, 2

• If CTA is negative for a lower‑GI bleed, an upper endoscopy should be performed because 10–15% of severe hematochezia originates from the upper GI tract. 1, 2

Critical Pitfalls to Avoid

• Do not rush to colonoscopy or CT angiography before achieving hemodynamic stability; this delays definitive resuscitation and can worsen shock. 1, 2

• Do not assume bright‑red rectal bleeding always originates from the lower GI tract; up to 15% may stem from an upper‑GI source, especially with hemodynamic instability. 1, 2

• Blind surgical exploration without prior localization leads to re‑bleeding in up to 33% of cases and mortality of 33–57%, whereas radiologic localization reduces these rates to ≈10%. 1, 2

• Ongoing massive transfusion (≥6 units of packed red cells) or persistent instability despite aggressive resuscitation should prompt immediate angiography or operative intervention rather than colonoscopy. 2

Mortality Context

• Overall in‑hospital mortality for lower gastrointestinal bleeding is ≈3.4%, rising to ≈20% in patients requiring ≥4 units of packed red blood cells. 1, 2

• Mortality in lower GI bleeding is generally related to comorbidity rather than exsanguination, underscoring the importance of optimizing hemodynamics and managing underlying conditions. 1, 2