The Colon

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The Colon
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BLOOD SUPPLY OF THE COLON
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Physiological Function

• Fluid re-absorption
• reabsorbs 1.5-2 litres per day
• Storage
• Elimination
• Enteric flora

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Symptoms Signs in Colon Diseases
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Symptoms of Colonic Diseases

• Diarrhoea
• Constipation
• Incontinence
• Flatulence
• Pain
• Blood per rectum
• Systemic symptoms

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ALARM SYMPTOMS

• Later age of onset
• Weight loss
• Anaemia
• Blood loss
• Nocturnal symptoms
• Family history colon cancer

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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
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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

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Vascular Ectasia
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Signs of Colonic Disease

• Tenderness
• Rebound, guarding
• Mass
• Systemic signs
• Digital Rectal Examination

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Investigations

• Radiology
• Endoscopy

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Barium Enema
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Barium Enema
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Barium Enema
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Sigmoidoscopy
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Endoscopy
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Diseases of the Colon
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Diverticular Disease
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Diverticular Disease

• Very common - gt50 in over 50s
• 90 asymptomatic
• Symptomatic gt10
• Haemorrhage 25 sts massive
• Diverticulitis 75

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NATURAL HISTORY OF DIVERTICULAR DISEASE
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Symptomatic Simple Diverticular Disease

• Colicky LIF pain
• Constipation
• STS rectal bleeding
• Treatment
• Fibre
• Stool softeners

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Complicated Diverticular Disease

• Mucosal inflammation diverticular colitis
• Subserosal inflammation diverticulitis
• Abscess
• Bleeding
• Obstruction
• Perforation/fistula

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ISCHEMIC COLITIS

• Elderly arteriopaths
• CV risk factor profile
• Often after hypotensive episode
• Pain first, often mild
• Bleeding diarrhoea

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BLOOD SUPPLY OF COLON
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Investigations

• PFA thumb printing
• Endoscopy
• rectal sparing
• segmental involvement
• CT scanning

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ISCHEMIC COLITIS
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Ischemic Colitis
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Management

• Conservative approach
• iv fluids, treat anaemia
• Nutrition
• 10 later stricture
• Surgery for gangrene of colon

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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

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RISK FACTORS

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

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ANTIBIOTICS CDAD
Frequently associated Occasionally associated Rarely associated
fluoroquinolones macrolides aminoglycosides
clindamycin trimethoprim tetracyclines
Penicillin (broad spectrum) sulphonamides chloramphenicol
cepalosporins metronidazole
vancomycin
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CLINICAL MANIFESTATIONS

• Spectrum asymptomatic to toxic megacolon
• Watery diarrhoea cardinal feature
• Offensive
• Often prominent systemic features
• Pseudomembranes on endoscopy

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MANAGEMENT

• Stop antibiotics
• Infection control
• Supportive therapy
• Treat on suspicion
• Metronidazole or vancomycin
• Rarely surgery
• Relapses

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Inflammatory Bowel Disease

• Ulcerative colitis
• Crohns disease
• Microscopic colitis
• Lymphocytic colitis
• Collagenous colitis

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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

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Crohns 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.

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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
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Crohns Disease
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Crohns Disease
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Distribution of Crohns Disease
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Ulcerative Colitis
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Crohns Disease
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Ulcerative Colitis
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Crohns Disease
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Ulcerative Colitis
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Causes of Diarrhoea in Crohns 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


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Colon Carcinoma
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COLORECTAL CANCER

• Polyp-dysplasia-cancer sequence
• genetic
• environmental

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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

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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

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Investigation

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

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Colon Carcinoma
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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

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Treatment

• Surgery
• Chemotherapy
• Radiotherapy

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Screening

• To detect cancer at treatable stage
• Age gt 50 years
• Targeted screening

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Screening

• Faecal occult blood
• Sigmoidoscopy
• Colonoscopy
• Virtual colonoscopy

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Colon Polyp
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Colon Polyp
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Virtual Colonoscopy
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Virtual Colonoscopy
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