Lower Gastrointestinal Bleeding ✅

Related Subjects: | Ulcerative Colitis | Microscopic Colitis | Irritable Bowel Syndrome | Lower GI Bleeding |Rectal Prolapse |Anal Cancer |Anal Fissure |Perianal symptoms |Perianal abscesses and fistulae |Pilonidal Abscess (sinus) |Haemorrhoids (Piles) |Faecal Incontinence

💉 Lower Gastrointestinal Bleeding (LGIB) = bleeding distal to the ligament of Treitz. ⚠️ Can range from mild self-limited bleeding to life-threatening haemorrhage. 🚨 Haemodynamic instability, Hb drop ≥2 g/dL or need for ≥2 units transfused within 24 h = emergency. 💡 Always consider an upper GI source if patient unstable with haematochezia (massive UGIB may present this way).

🩺 Initial Management (Resuscitation First!)

• 🏥 Admission: Usually under Lower GI Surgery with gastroenterology input. Rapid deterioration possible → senior oversight essential.
• 🫁 Airway & Breathing: High-flow O₂ if hypoxic. Consider intubation if altered conscious level, shock, or massive bleed. Monitor SpO₂, ABG if severe.
• 💉 Circulation: Two wide-bore IV cannulae. Send baseline bloods: FBC (anaemia), U&E, LFTs, clotting profile, CRP, group & save / crossmatch. Begin IV crystalloids (0.9% saline / balanced solution). 🚨 Activate major haemorrhage protocol for ongoing shock or massive bleeding (>1.5 L in 24 h).
• 🩸 Transfusion: Restrictive strategy guided by Hb: aim >70 g/L for most, 80–90 g/L if elderly or with cardiac comorbidity. Massive bleeds → balanced PRBC:FFP:platelet ratio. Reverse anticoagulants (Vitamin K ± PCC for warfarin; idarucizumab for dabigatran; andexanet alfa for factor Xa inhibitors) as needed.
• 📊 Monitoring: Continuous vitals, urine output, stool chart. Hb repeated every 4–6 h if active bleeding. Consider ICU/ITU if hypotensive or requiring vasopressors.
• 🧪 Risk Stratification: Use scoring tools like **Oakland score** for LGIB to determine safe discharge vs need for admission.

🔎 Pathophysiology & Common Sources

• 💊 Diverticular bleeding: Rupture of submucosal artery → painless, brisk haematochezia; often stops spontaneously in 70–80%.
• 🔥 Inflammatory colitis: Ulcerative colitis, Crohn’s, ischaemic colitis → usually painful, may be systemic upset.
• 🌱 Angiodysplasia / vascular lesions: Submucosal dilated vessels → intermittent, often in elderly, CKD, or aortic stenosis (“Heyde syndrome”).
• 💉 Post-polypectomy / iatrogenic: Mechanical injury or anticoagulation-related.
• 🍑 Anal / rectal lesions: Haemorrhoids, fissures, rectal cancer.
• 🧪 Colorectal malignancy: Bleeding often occult, associated with anaemia, altered bowel habit, weight loss.

⚠️ Risk Factors for Severe Bleeding

• Age >70 years
• Multiple comorbidities (≥2) including cardiac, renal, hepatic disease
• Hypotension (SBP <115 mmHg), tachycardia (>100 bpm)
• Active anticoagulation / antiplatelets
• Known diverticulosis, IBD, vascular malformations
• Frailty / poor physiological reserve

🔧 Investigations

• 🩸 Blood tests: FBC, U&E, LFTs, coagulation profile, CRP, group & save, iron studies if anaemic.
• 📷 Colonoscopy: Gold standard if stable; allows diagnosis and therapy (endoscopic clips, diathermy, adrenaline injection). Usually performed within 24 h of stabilisation in acute bleed.
• 🔎 Sigmoidoscopy: Useful for distal lesions, flexible or rigid.
• 🧲 CT Angiography: First-line if ongoing bleeding and unstable; localises source for potential IR embolisation.
• 💉 Interventional Radiology (IR): Angiographic embolisation for active bleeding, especially diverticular or angiodysplastic source.
• 🔪 Surgery: Subtotal colectomy with end ileostomy for uncontrolled bleeding; indicated if ≥4–5 units transfused in 24 h, haemodynamic instability, or failed endoscopic/IR therapy.
• 📌 Adjunct: OGD if suspicion of UGIB (haematochezia + shock or melena history), capsule endoscopy if obscure bleeding.

📋 Causes Table (Mnemonic = DRAIN IT)

⚕️ Management Summary (Stepwise)

• 🚑 Immediate: ABC → airway, high-flow O₂, IV access, fluids, correct coagulopathy.
• 💉 Transfusion: Restrictive Hb target, reverse anticoagulation as per NICE/BCSH guidelines.
• 📷 Stable patient: Colonoscopy within 24 h → diagnosis + therapy.
• 🧲 Unstable or ongoing: CT angiography → interventional radiology embolisation.
• 🔪 Surgery: Indicated if bleeding uncontrolled despite resuscitation, ≥4–5 units transfused in 24 h, or IR unavailable/failed.
• 📌 Post-stabilisation: Treat underlying pathology (IBD, malignancy, diverticulosis, vascular lesions). Prevent recurrence: anticoagulation review, manage comorbidities, dietary advice for diverticular disease.

💡 Teaching Pearls / Exam Tips

• Painless massive bleed = diverticulosis or angiodysplasia 🌱
• Painful bleed = fissure, IBD, ischaemia 🔥
• Bright red blood in elderly → always consider malignancy 🍑
• Haematochezia + shock may be UGIB → OGD may be required ⚠️
• Always correct coagulopathy (warfarin/DOAC reversal) 💊
• Frailty increases mortality risk 🚨
• Mnemonic “DRAIN IT” helps recall causes: Diverticula, Rectal, Adenocarcinoma, Inflammatory, Neovascular, Iatrogenic, Trauma
• Early senior involvement, ABC, monitoring, and escalation to IR or surgery are key NICE principles ✅

📚 References (NICE-compliant)

• NICE Guideline: Acute upper and lower gastrointestinal bleeding
• Lower GI Bleeding: Epidemiology & Management
• ACG Guideline: Acute Lower GI Bleeding