21 - Pathology of the GI Tract - 2 Flashcards
Epidemiology of diverticulosis
Common in developed western world
Rare in Africa, Asia, S.America
Common in urban
Relationship with fibre content of diet
Pathogenesis of diverticulosis
Increased intra-luminal pressure -> irreguar, uncoordinated peristalsis.
Points of relative weakness in bowel wall
Pathology of diverticulosis
Thickening of muscularis propria
Elastosis of taeniae coli
Redundant mucosal folds and ridges
Sacculation and diverticula
Diverticular disease - clinical features
Asymptomatic (90%-99%)
Cramping abdominal pain
Alternating constipation and diarrhoea
Acute and chronic complications (10-30%)
Diverticular disease - complications
Acute - diverticulitis (20%), perforation, haemorrhage
Chronic - intestinal obstruction, fistula, diverticular colitis, polypoid prolapsing mucosal folds
Classification of colitis
inflammation of the colon
Usually mucosal inflammation but occasionally transmural or predominantly submucosal/muscular
Divided into acute / chronic
Causes of acute colitis
Acute infective colitis Antibiotic associate colitis Drug induced colitis Acute ischaemic colitis Acute radiation colitis Neutropenic colitis Phlegmonous colitis
Causes of chronic colitis
Chronic idiopathic inflammatory bowel disease Microscopic colitis Ischaemic colitis Diverticular colitis Chronic infective colitis Diversion colitis Eosinophilic colitis Chronic radiation colitis
Idiopathic inflammatory bowel disease e.g.s
Ulcerative colitis
Crohn’s disease
Indeterminate colitis
Epidemiology of IBD - area
5-15 cases per 100,000 pa
Incidence highest in Scandinavia, UK, Northern Europe, USA
Lower in Japan, Southern Europe, Africa
Epidemiology of IBD - age
Peak age incidence 20-40 years of age
CD more common in females 1.3:1
UC equally common in males and females
Risk factors for IBD
Cigarette smoking Oral contraceptive Childhood infections MMR Domestic hygiene Appendicectomy
Ulcerative colitis - clinical presentation
Diarrhoea (>66%) Constipation Rectal bleeding Ab pain Anorexia Weight loss Anaemia
Ulcerative colitis - complications
Toxic megacolon and perforation
Haemorrhage
Stricture
Carcinoma
Crohn’s Disease - clinical features
Chronic relapsing disease Affects all levels of GIT from mouth to anus Diarrhoea Colicky ab pain Palpable ab mass Weight loss / failure to thrive Anorexia Fever Oral ulcers Peri-anal disease Anaemia
Crohn’s Disease - complications
Toxic megacolon Perforation Fistula Stricture Haemorrhage Carcinoma Short bowel syndrome
UC vs Crohns - area of GIT
colon, appendix & terminal ileum vs all parts
UC vs Crohns - how it looks in colon
Continuous vs skip lesions
UC vs Crohns - involvement of rectum
Always involved vs rectum normal in 50%
UC vs Crohns - terminal ileum involvement
10% vs 30% chance
UC vs Crohns - pathology
Granular red mucosa with flat, undermining ulcers vs cobblestone appearance with apthoid and fissuring ulcers
UC vs Crohns - serosa
Normal vs serositis (fat wrapping)
UC vs Crohns - strictures present
Rare vs common
UC vs Crohns - fistulae
No spontaneous vs 10% presence
UC vs Crohns - anal lesion presence chance
25% vs 75%
UC vs Crohns - pathology - invasion of mucosa
Mainly mucosal vs transmural
UC vs Crohns - pathology - crypt abscesses
Common vs less common
UC vs Crohns - pathology - crypt distortion
Severe vs less severe
UC vs Crohns - pathology - granulomas presence
Sarcoid like granulomas present in 60%
UC vs Crohns - pathology - polyps
Inflammatory polyps common vs uncommon
Extra-intestinal manifestations of IBD - hepatic
Fatty change
Granulomas
PSC
Bile duct carcinoma
Extra-intestinal manifestations of IBD - skeletal
Polyarthritis
Sacro-ileitis
Ankylosing spondylitis
Extra-intestinal manifestations of IBD - muco-cutaneous
Oral apthoid ulcers
Pyoderma gangrenosum
Erythema nodoum
Extra-intestinal manifestations of IBD - ocular
Iritis/uveitis
Episcleritis
Retinitis
Extra-intestinal manifestations of IBD - renal
Kidney and bladder stones
Extra-intestinal manifestations of IBD - Haematological
Anaemia
Leucocytosis
Thrombocytosis
Thrombo-embolic disease
Extra-intestinal manifestations of IBD - systemic
Amyloid
Vasculitis
Risk factors in UC
Early age of onset Duration of disease >8-10 years Total or extensive colitis PSC Family history CRC Severity of inflammation Presence of dysplasia
Colorectal polyps - what are they?
Mucosal protrusion Solitary or multiple polyposis Pedunculated, sessile or flat Small or large Due to mucosal or submucosal pathology or a lesion deeper in the bowel wall
Colorectal polyps - classifications
Neoplastic, hamartomatous, inflammatory or reactive
Benign or malignant
Epithelial or mesenchymal
Hamartomatous polyps types
Peutz-jeghers polyps
Juvenile polyps
Hyperplastic polyps
Common 1-5mm in size Often multiple Located in rectum & sigmoid colon Small distal hyperplastic polyps have no malignant potential
Juvenile polyp
Spherical and pedunculated
10-30mm
Commonest type of polyp in children
Typically occur in rectum & distal colon
Sporadic polyps have no malignant potential
Peutz-jeghers syndrome
AD condition 1 in 50,000 - 1 in 120,000 Present clinically in teens or 20s with ab pain, gi bleeding & anaemia Multiple GI tract polyps Muco-cutaneous pigmentation
Benign polyp-types
Adenoma Lipoma Leiomyoma Haemangioma Neurofibroma
Malignant polyp-types
Carcinoma Carcinoid Leiomyosarcoma GIST Lymphoma Metastatic tumour
What is an adenoma?
Benign epithelial tumour
What do adenomas look like?
Pedunculated sessile or flat
Villous, tubulo-villous or tubular
Grade histologically by high grade vs low grade
What is progression of an adenoma?
To adenocarcinoma
Usually over 10-15 years
What factors affect progression of an adenoma?
Flat adenomas = increase Size (>10mm is usually malignant) Villous & tubulo-villous High dysplasia HNPCC associated adenomas
Risk factors for colorectal cancer
Diet - fibre, fat, red meat, folate, calcium Obesity Alcohol NSAIDs HRT & oral contraceptives Schistomiasis Pelvic radiation Ulcerative colitis and crohn's
What 3 letter genetic condition makes you get colorectal cancer?
FAP AD 100% lifetime risk of large bowel cancer Multiple benign adenomatous polyps in colon Mutation in APC tumour suppressor gene
What 5 letter genetic condition makes you get colorectal cancer?
HNPCC
1-2% of colorectals
Heriditary non-polyposis colorectal cancer
AD
50-70% lifetime risk
Increased chance of other GI and genitourinary cancers
Due to mutations in DNA mismatch repair genes
Where are most colorectal cancers found?
Rectum
Sigmoid colon
What type of cancer is most common form of colorectal cancer?
Adenocarcinoma (95%)
Where can colorectal cancer spread?
Direct invasion of adjacent tissues
Lymphatically to lymph nodes
Via blood to liver and lung
Transcoelomic mets through peritoneum
TNM staging
N0 - no nodes involved
N1 - 1-3 nodes involved
N2 - 4 or more nodes involved
Dukes staging
Stages A-D
Stage A (Duke’s)
Adenocarcinoma confined to bowel wall with no lymph node mets
Stage B (Duke’s)
Adenocarcinoma invading through bowel wall with no lymph node mets
Stage C (Duke’s)
Adenocarcinoma with regional lymph node mets regardless of depth of invasion
Stage D (Duke’s)
Distant mets present
Frequency of each Duke stage
A: 15%
B: 35%
C: 45%
D: 20%
5 yr survival of each Duke stage
A: 90%
B: 70%
C: 45%
D:
