1. Lower GI Bleeding

2. Presentation Iron deficiency anaemia PR bleeding
Acute colonic bleeding

3. Bleeding with defecation
History
How much?
Mixed in with the stool? Colour?
Pain on defecation?
Pattern of bleeding – remissions, exacerbations?
Constipation (anal fisure) or diraahoea Ulcerative colitis)
Associated symptoms – tenesmus, signs of malignancy
Examination
Anal inspection – external hemorrhoids (internal via straining), anal fissure
PR Exam – ulcerative lesion (carcinoma – especially with blood on gloved finger), spasm of Int sphincter may make Ex impossible (anal fissure)
Proctoscopy – 1st and 2nd degree haemorrhoids (non palpable), lower rectal carcinoma, anal fissure

4. DDx Haemorrhoids Carcinoma of rectum/sigmoid colon Anal fissure
Adenomatous polyp
IBD (with diarrhoea)

5. Haemorrhoids
Internal Haemorrhoids: prolapse of the anal mucosa (anal cushions) containing the internal rectal venous plexus. Prolapse often lead to strangulation and ulceration
External Haemorrhoids: thrombosis of external rectal venous plexus. Caused by anything that impedes venous return, pregnancy, constipation and extended toilet sitting and straining
Pattern of bleeding: bleeding at the end of defecation, bright red, seen on toilet paper
Clinically painless – prolapse may lead to moderate discomfort
Portal Hypertension

6. Rectal/sigmoid carcinoma
Bleeding of recent onset, colour depends on location, mixed with bowel motion, persists without remission
Recent history of increasing tenesmus (feeling of incomplete evacuation)

7. Anal Fissure
Tear in the skin of the lower anal canal – distal to the dentate line
Leads to spasm of the internal sphincter – impedes healing
Usually caused by constipation – leads to severe pain, leads to further constipation, exacerbating the condition

8. Adenomatous Polyp Bleeding without change in bowel habit Intermittent
Colour depends on location
Large benign tumours may cause tenesmus and mucus in bowel motions (diarrhoea)

9. Iron Deficiency Anaemia
No clinical evidence pointing towards bleeding
Must do a full system review and examination due to many causes of iron deficiency anaemia
DDx: carcinoma of the caecum, Crohn’s disease (more often normocytic anaemia of chronic disease). Other Upper GI problems.

10. Acute Haemorrhage Massive Lower GI bleeding is very RARE
Is ACUTE but reasonably benign compared to acute UPPER GI bleeding
Perforated peptic ulcer may lead to passage of bright red blood per rectum – VERY SEVERE AND LEADING TO SHOCK
Usually spontaneously resolves
DDx: Diverticular disease, angiodysplasia, ischaemic colitis, IBD, polyp/carcinoma (rare), Meckel’s diverticulum

11. Angiodysplasia
Vascular malformation of the colon – usually caecum and ascending colon – multiple lesions
GI bleeding (hematochezia/melena) and anaemia
Bleeding – risk increased with a coagulation disorder
Patients usually over 60

12. Ischaemic Colitis
Sudden onset crampy left lower quadrant pain followed by hematochezia within 24 hours
Sudden and transient reduction of blood flow – usually splenic flexure and left colon - limited collateral supply
Usually mucosal (not transmural) therefore complications of stricture of gangrenous colitis are rare
Often misdiagnosed as IBD or infectious colitis