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
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Diarrhoea
Constipation
Incontinence
Flatulence
Pain
Blood per rectum
Systemic symptoms
ALARM SYMPTOMS
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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,
Foregut
gastric, duodenal
T5-6 to T8-9
Epigastric
Small intestine to Midgut
transverse colon
T8-11 to L1
Peri-umbilical
Transverse to
recto-sigmoid
T11 to L1
Suprapubic
Hindgut
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
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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
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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
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Conservative approach
iv fluids, treat anaemia
Nutrition
10% later stricture
Surgery for gangrene of colon
C. difficile
• Anaerobic gram-positive, spore-forming, toxinproducing 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
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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)
cepalosporins
sulphonamides
chloramphenicol
metronidazole
vancomycin
CLINICAL MANIFESTATIONS
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Spectrum: asymptomatic to toxic megacolon
Watery diarrhoea cardinal feature
Offensive
Often prominent systemic features
Pseudomembranes on endoscopy
MANAGEMENT
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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
mucosal inflammation
bacterial overgrowth
bile salt diarrhoea
bile acid deficiency
lactase deficiency
short bowel
internal fistulae
antibiotics (c. diff)
Treatment
anti-inflammatory Rx
antibiotics
cholestyramine
low fat diet
avoid latose
low fat diet
surgery
treat
Colon Carcinoma
COLORECTAL CANCER
• Polyp-dysplasia-cancer sequence
– genetic
– environmental
Clinical Features
– Depends on site of tumour
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1/3 proximal to splenic flexure
Bleeding
Change in bowel pattern
Fe deficiency anaemia
Pain non-specific
Systemic features late
Metastatic
CLINICAL FEATURES
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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
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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
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Faecal occult blood
Sigmoidoscopy
Colonoscopy
Virtual colonoscopy
Colon Polyp
Colon Polyp
Virtual Colonoscopy
Virtual Colonoscopy