|
|
Ulcerative
colitis
|
Crohn’s
disease
|
|
Epidemiology
|
|
|
UK incidence
|
5:100,000(constant) |
5:100,000(increasing) |
|
Age
on onset |
Peak
20-39 years |
Peak late teens
|
|
Age
of diagnosis |
Soon after onset of
symptoms
|
20-39
years |
|
Sex
distribution |
1:1 |
1:1.5 |
|
Geographical
distribution |
More
common in Anglo-Saxon/European |
More
common in Anglo-Saxon/European |
|
Associated
factors |
HLA-B27 |
Smoking |
|
Implicated
theories |
Autoimmune
disease against mucosal cytoplasmic antigen |
Ø
Measles
virus hypersensitivity reaction Ø
Pseudotuberculosis
organism infection Ø
Milk
protein hypersensitivity Ø
Toxic
effect of small bowel chyme contents |
Clinical Features
|
|
|
|
Rectal
bleeding |
Common |
Unusual |
|
Abdominal
pain |
Infrequent |
Common |
|
Abdominal
mass |
Rare |
Sometimes |
|
Spontaneous
fistula |
Rare/
never |
Sometimes |
|
Perennial
infection |
15% |
40% |
|
Rectal
involvement |
95% |
50% |
|
Carcinoma |
Yes |
Yes |
Radiology
|
|
|
|
Distribution |
Continuous
with rectum |
Often
discontinuous along and around colon |
|
Rectum |
Often
involved |
Often
normal |
|
Stricture |
Rare/
usually Carcinoma |
Often
present |
|
mucosal |
Granular,
shallow
ulcers, pseudopolyp |
Fissuring,
deep
undermining ulcers, cobble
stone appearance |
|
Small
bowel |
Backwash
ileitis |
Discontinuous
involvement by skip lesion |
|
Histopathology
|
|
|
|
Inflammation |
Mucosal |
Transmural |
|
Vascularity |
Often
intense |
Seldom
prominent |
|
Focal
lymphoid hyperplasia |
Restricted
to mucosa/ submucosa |
Transmural |
|
Mucus
secretion |
Grossly
impaired |
Less
severe impairment |
|
Paneth
cell metaplasia |
Common |
Rare |
|
Sarcoid
granuloma |
Absent |
50-70% |
|
Fissuring |
Rare |
Very
common |
|
Precancerous
dysplasia |
Yes |
Yes |
|
Lymph
nodes |
Reactive
hyperplasia |
Often
Sarcoid foci |
|
Anal
lesion |
Non
specific |
Often
Sarcoid foci |