The Colon

BLOOD SUPPLY OF THE COLON

Physiological Function

• Fluid re-absorption– reabsorbs 1.5-2 litres per day

• Storage• Elimination• Enteric flora

Symptoms & Signs in Colon Diseases

Symptoms of Colonic Diseases

• Diarrhoea

• Constipation

• Incontinence

• Flatulence

• Pain

• Blood per rectum

• Systemic symptoms

ALARM SYMPTOMS

• Later age of onset

• Weight loss

• Anaemia

• Blood loss

• Nocturnal symptoms

• Family history colon cancer

Origin of Abdominal Pain

Intestinal structures

Embryological origin

Spinal segments Pain location

Oesophagus, gastric, duodenal

Foregut T5-6 to T8-9 Epigastric

Small intestine to transverse colon

Midgut T8-11 to L1 Peri-umbilical

Transverse to recto-sigmoid

Hindgut T11 to L1 Suprapubic

Common causes of lower gastrointestinal bleeding

• Anatomical– Diverticulosis

• Vascular– Haemorrhoid– Angiodysplasia– Ischemic– Radiation-induced telangiectasia

• Inflammatory– Infectious– Idiopathic inflammatory bowel disease

• Neoplastic– Polyp– Carcinoma

• Others– Ulcer– Post biopsy or polypectomy

Vascular Ectasia

Signs of Colonic Disease

• Tenderness

• Rebound, guarding

• Mass

• Systemic signs

• Digital Rectal Examination

Investigations

• Radiology

• Endoscopy

Barium Enema

Barium Enema

Barium Enema

Sigmoidoscopy

Endoscopy

Diseases of the Colon

Diverticular Disease

Diverticular Disease

• Very common - >50% in over 50’s

• 90% asymptomatic

• Symptomatic >10%

– Haemorrhage 25% sts massive

– Diverticulitis 75%

NATURAL HISTORY OF DIVERTICULAR DISEASE

Symptomatic Simple Diverticular Disease

• Colicky LIF pain

• Constipation

• STS rectal bleeding

• Treatment:– Fibre – Stool softeners

Complicated Diverticular Disease

• Mucosal inflammation – diverticular colitis

• Subserosal inflammation – diverticulitis

– Abscess

– Bleeding

– Obstruction

– Perforation/fistula

ISCHEMIC COLITIS

• Elderly arteriopaths

• CV risk factor profile

• Often after hypotensive episode

• Pain first, often mild

• Bleeding & diarrhoea

BLOOD SUPPLY OF COLON

Investigations

• PFA – “thumb printing”• Endoscopy

– rectal sparing– segmental involvement

• CT scanning

ISCHEMIC COLITIS

Ischemic Colitis

Management

• Conservative approach

• iv fluids, treat anaemia

• Nutrition

• 10% later stricture

• Surgery for gangrene of colon

C. difficile

• Anaerobic gram-positive, spore-forming, toxin-producing bacillus 1935

• 1978 - c. diff identified as cause of antibiotic related diarrhoea – mostly clindamycin

• fecal-oral route

• Toxins A & B

• Recently hypervirulent strain – 027

• Exponential increase

RISK FACTORS

– antibiotic use– hygiene/handwashing– hospitalisation/overcrowding– advanced age– PPIs– GI surgery– enteral feeding

ANTIBIOTICS & CDAD

Frequently associated

Occasionally associated

Rarely associated

fluoroquinolones macrolides aminoglycosides

clindamycin trimethoprim tetracyclines

Penicillin (broad spectrum)

sulphonamides chloramphenicol

cepalosporins metronidazole

vancomycin

CLINICAL MANIFESTATIONS

• Spectrum: asymptomatic to toxic megacolon

• Watery diarrhoea cardinal feature

• Offensive

• Often prominent systemic features

• Pseudomembranes on endoscopy

MANAGEMENT

• Stop antibiotics

• Infection control

• Supportive therapy

• Treat on suspicion

• Metronidazole or vancomycin

• Rarely surgery

• Relapses

Inflammatory Bowel Disease

• Ulcerative colitis

• Crohn’s disease

• Microscopic colitis– Lymphocytic colitis– Collagenous colitis

Ulcerative Colitis

•  Ulcerative colitis is characterized by recurring episodes of inflammation limited to the mucosal layer of the colon. It almost invariably involves the rectum and may extend in a proximal and continuous fashion to involve other portions of the colon

Crohn’s Disease

Crohn's disease is characterized by transmural rather than superficial mucosal inflammation and by skip lesions rather than continuous disease. The transmural inflammatory nature of Crohn's disease can lead to stricture formation, microperforations and fistulae. Crohn's disease may involve the entire gastrointestinal tract from mouth to perianal area.

Comparisons of various factors in Crohn's disease and ulcerative colitis

Crohns UC

rectum involved uncommom yes

anus involved yes no

TI involved often no

colon involved often always

PSC less common more commom

Endoscopy Ulcers continuous

Inflammation Transmural superficial

Inflammation Skip continuous

fistulae/stenoses Yes no

Granulomas Often no

Smoking increases risk lowers risk

Surgical cure no yes

Appendicectomy No influence protective

Crohn’s Disease

Crohn’s Disease

Distribution of Crohn’s Disease

Ulcerative Colitis

Crohn’s Disease

Ulcerative Colitis

Crohn’s Disease

Ulcerative Colitis

Causes of Diarrhoea in Crohn’s Disease

Consideration Treatment

mucosal inflammation anti-inflammatory Rx

bacterial overgrowth antibiotics

bile salt diarrhoea cholestyramine

bile acid deficiency low fat diet

lactase deficiency avoid latose

short bowel low fat diet

internal fistulae surgery

antibiotics (c. diff) treat

Colon Carcinoma

COLORECTAL CANCER

• Polyp-dysplasia-cancer sequence

– genetic– environmental

Clinical Features

– Depends on site of tumour

– 1/3 proximal to splenic flexure

– Bleeding

– Change in bowel pattern

– Fe deficiency anaemia

– Pain non-specific

– Systemic features late

– Metastatic

CLINICAL FEATURES

• Abdominal pain — 44 percent

• Change in bowel habit — 43 percent

• Hematochezia or melena — 40 percent

• Weakness — 20 percent

• Anemia without other gastrointestinal symptoms — 11 percent

• Weight loss — 6 percent

Investigation

• Sigmoidoscopy/Colonoscopy• Biopsy• Barium studies• CT scanning

Colon Carcinoma

Dukes classification

Dukes A - limited to bowel wall

Dukes B - extends thro’ muscle wall

Dukes C - LN involvement - C1 & C2

Dukes D - outside bowel wall

Treatment

• Surgery

• Chemotherapy

• Radiotherapy

Screening

• To detect cancer at treatable stage

• Age > 50 years

• Targeted screening

Screening

• Faecal occult blood• Sigmoidoscopy• Colonoscopy• Virtual colonoscopy

Colon Polyp

Colon Polyp

Virtual Colonoscopy

Virtual Colonoscopy