PR Bleed (Rectal Bleeding) 🩸
Clinical guide for assessing and managing PR bleed (rectal bleeding). Causes, red flags, investigations, when to refer to surgery or gastroenterology for on-call doctors.
🔍 Context
- PR bleed can be fresh (haematochezia – red/maroon), dark (melena – upper GI source), or mixed. Volume and haemodynamic impact matter as much as colour.
- Establish: volume (spotting vs. clots vs. large), colour, associated symptoms (abdominal pain, collapse, change in bowel habit), anticoagulation, and past GI history.
📋 History
- Volume and frequency: spotting on tissue vs. blood in toilet vs. clots or large volume.
- Colour: bright red (often lower GI – anal canal, rectum, left colon), dark/maroon (right colon or upper GI), melena (upper GI – stomach/duodenum).
- Pain: anal pain (fissure, haemorrhoids), abdominal pain (ischaemia, colitis, perforation).
- Bowel habit: constipation (fissure), diarrhoea (colitis, infection), change in calibre (malignancy).
- Anticoagulants, antiplatelets, NSAIDs. Previous GI bleed, diverticular disease, inflammatory bowel disease, malignancy.
🩺 Examination
- Vitals: pulse, BP, postural drop – assess for shock and need for resuscitation.
- Abdominal exam: tenderness, distension, masses, bowel sounds.
- PR exam if appropriate: tone, masses, blood on glove, colour of stool (melena vs. fresh). Document findings.
🔎 Common causes
| Cause | Typical features |
|---|---|
| Haemorrhoids | Bright red, on wiping or after stool; often chronic; anal discomfort |
| Anal fissure | Bright red, painful defaecation; small volume |
| Diverticular disease | Often painless, moderate volume; can be massive; left colon |
| Colorectal cancer | Change in bowel habit, weight loss; may be mixed or dark blood |
| Colitis (IBD, infective, ischaemic) | Blood mixed with diarrhoea; abdominal pain; ischaemic in elderly/vascular disease |
| Upper GI bleed | Melena (black tarry stool) or large haematochezia if brisk; consider if shocked |
| Angiodysplasia | Painless, intermittent; often elderly |
| Anticoagulation / antiplatelets | Warfarin, DOACs, aspirin, clopidogrel – can exacerbate or unmask any GI source; check INR/coagulation |
🚩 Red flags / escalate
- Haemodynamic instability: tachycardia, hypotension, postural drop – resuscitate and escalate to senior/surgery immediately.
- Large-volume or ongoing bleed – may need urgent endoscopy or surgery.
- Severe abdominal pain (ischaemic colitis, perforation).
- Suspected upper GI source (melena, history of PUD/liver disease) – may need gastroscopy.
- Significant anaemia or drop in Hb. Altered consciousness or collapse.
🧪 Investigations
- FBC (Hb, repeat if bleeding ongoing), U&E, coagulation screen, group and save or crossmatch if significant bleed.
- Lactate if shocked. Consider LFTs if upper GI or liver disease likely.
- Stool culture if diarrhoea (infective colitis).
- Imaging: CT abdomen/pelvis if ?ischaemia, perforation, or mass; CT angiography if active bleed and haemodynamically stable for localisation.
- Endoscopy (OGD for melena/upper GI; colonoscopy for lower GI) as per senior/gastro/surgical advice – often after resuscitation and stabilisation.
💊 Management
- Resuscitate first: IV access, fluids, blood products as needed; correct coagulopathy per local protocol.
- Nil by mouth if significant bleed or likely endoscopy; discuss with senior.
- Hold anticoagulants/antiplatelets as per senior/gastro/surgery and bleeding risk vs. thrombotic risk.
- Treat cause when identified: local measures for haemorrhoids/fissure; gastroenterology for colitis, angiodysplasia, upper GI; surgery for massive bleed, perforation, or when endoscopy not controlling bleed.
📞 When to refer
- Surgery: haemodynamically unstable, massive bleed, suspected perforation or ischaemic bowel, or when endoscopy unavailable and bleed life-threatening.
- Gastroenterology: melena/upper GI bleed (OGD), lower GI bleed for colonoscopy, known IBD flare, or for endoscopic therapy.
- Discuss with senior early when in doubt; document vitals, examination, and plan clearly.