💉 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)

Cause	Typical Features	Diagnosis	Management
Diverticular disease	Painless, massive haematochezia ± clots	CT colonography / colonoscopy	Conservative if stops, endoscopic therapy if ongoing, surgery if refractory
Haemorrhoids	Bright red blood coating stool, pruritus	Proctoscopy / exam	Conservative: fibre, hydration, topical agents; band ligation if persistent
Fissure-in-ano	Painful defecation + blood	Exam / anoscopy	Sitz baths, stool softeners, GTN ointment, lateral sphincterotomy if chronic
Colorectal cancer	Bleeding + altered bowel habit, anaemia, weight loss	Colonoscopy + biopsy	Surgical resection ± adjuvant therapy
Inflammatory colitis (UC/Crohn)	Bloody diarrhoea ± systemic upset	Sigmoidoscopy / biopsy	Medical therapy (steroids, 5-ASA, biologics), surgery if refractory
Angiodysplasia / vascular malformations	Intermittent, often in elderly, CKD, aortic stenosis	Colonoscopy, CT angiography, capsule endoscopy	Endoscopic coagulation, IR embolisation if severe, surgery if refractory
Iatrogenic / trauma	Post-polypectomy, anticoagulation-related	Endoscopy	Endoscopic therapy, correct coagulopathy, surgical intervention if severe

⚕️ 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)

Additional related clinical topics

OSCE Rectal Bleeding

Candidate Instructions:You are the medical student in an outpatient clinic. A 62-year-old patient has been referred by their GP with rectal bleeding. Take a focused history, assess for red-flag symptoms, and outline your initial management plan. You do not need to perform a physical examination. You have 8 minutes.

Key Learning Points 🔑

Rectal bleeding = alarm symptom 🚨, must exclude colorectal cancer.
Most causes are benign (haemorrhoids, fissures), but don’t miss cancer, polyps, IBD, diverticulosis.
Always ask about quantity, colour, association with stool, and systemic features.

History Framework 📝

Onset & Duration: When did bleeding start? Single or recurrent episodes?
Character: Bright red vs dark, mixed with stool or coating stool?
Associated Bowel Symptoms: Change in bowel habit, diarrhoea, constipation, mucus, tenesmus.
Systemic: Weight loss, night sweats, anorexia, fatigue, anaemia symptoms.
Past History: Haemorrhoids, IBD, diverticulitis, bowel polyps, family history of colorectal cancer.
Medications: Anticoagulants, NSAIDs.
Lifestyle: Smoking, alcohol, diet (fibre, red meat).

Role-Player Prompts 👩‍⚕️

Bleeding noticed for 6 weeks, bright red, coating the stool and on toilet paper.
No pain on defecation, occasional mucus.
Increasing constipation and feeling of incomplete emptying.
Lost 4 kg unintentionally in the past 3 months, feels more tired.
No previous bowel disease. Father had bowel cancer at age 70.
Smokes 15/day, drinks 20 units/week.

Differential Diagnosis ⚖️

Colorectal cancer 🚩
Colorectal polyp
Haemorrhoids
Anal fissure
Diverticular disease
Inflammatory bowel disease (UC, Crohn’s)
Angiodysplasia

Investigations 🔬

Urgent 2-week wait colonoscopy if ≥40 with unexplained weight loss + abdominal pain, or ≥50 with unexplained rectal bleeding, or ≥60 with iron deficiency anaemia/change in bowel habit.
Bloods: FBC (anaemia), U&E, LFTs, CRP, clotting.
Stool tests: FIT (faecal immunochemical test) for triage if low risk.
Flexible sigmoidoscopy – useful for distal lesions/haemorrhoids.
Imaging: CT colonography if colonoscopy contraindicated.

Management 🚑

Red-flag referral: Urgent 2-week wait colorectal clinic 🚨.
Supportive: Treat iron deficiency anaemia with oral iron; advise on fluid and fibre intake if constipation present.
Specific Causes:
- Colorectal cancer → surgical + oncology MDT management.
- Haemorrhoids → conservative (diet, fluids), banding, or surgical options if severe.
- IBD → gastroenterology referral, medical therapy (mesalazine, steroids, biologics).
- Diverticulitis → antibiotics, fluids, surgical review if complicated.

Examiner’s Marking Guide 📋

Introduces self, takes consent, explores bleeding in detail.
Asks about red flags: weight loss, anaemia, change in bowel habit, family history.
Considers benign vs malignant causes, but does not miss cancer.
Plans urgent referral appropriately.
Explains clearly and sensitively to patient.

References 📚

🧑‍⚕️ Case Examples - Rectal Bleeding

Case 1 (Haemorrhoids): 🚻 A 48-year-old office worker reports fresh red blood on toilet paper and streaks on the stool. No weight loss or change in bowel habit. Proctoscopy reveals internal haemorrhoids. Diagnosis: Symptomatic haemorrhoids. Teaching point: Bright red bleeding not mixed with stool is typical; managed with diet, topical treatments, or banding/surgery if persistent.
Case 2 (Anal fissure): ⚡ A 30-year-old woman presents with severe pain on defecation and small amounts of bright red blood on wiping. Examination shows a posterior midline fissure. Diagnosis: Anal fissure. Teaching point: Fissures cause pain + fresh bleeding; treat with stool softeners, topical GTN/diltiazem, and rarely lateral sphincterotomy.
Case 3 (Diverticular disease): 🩸 A 72-year-old man suddenly develops painless, large-volume fresh rectal bleeding. He is on aspirin for ischaemic heart disease. Colonoscopy shows diverticulosis in the sigmoid colon with recent bleeding. Diagnosis: Diverticular bleed. Teaching point: Diverticular bleeding is usually painless but can be brisk; most resolve spontaneously but endoscopic or surgical intervention may be needed.
Case 4 (Colorectal carcinoma): 🎗️ A 64-year-old woman complains of intermittent rectal bleeding mixed with stool, iron-deficiency anaemia, and a 3-month history of altered bowel habit. Colonoscopy shows a sigmoid tumour. Diagnosis: Colorectal cancer. Teaching point: Always exclude malignancy in older patients with rectal bleeding, particularly if associated with anaemia or bowel habit change.

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Lower Gastrointestinal Bleeding ✅