Alimentary Tract Pathology Flashcards
What types of cells are present in the mucosa of the small bowel?
Goblet cells
Columnar absorptive cells
Endocrine cells
The myenteric plexus is formed of what?
Meissener’s plexus
Auerbach’s plexus
Where is Meissener’s plexus located?
Base of the submucosa
Where is Auerbach’s plexus located?
Between inner (circular) and outer (longitudinal) layers of muscularis propria
What is the definition of idiopathic inflammatory bowel disease?
Chronic inflammatory conditions from inappropriate and persistent activation of mucosal immune system in presence of NORMAL intraluminal flora
Which diseases make up the largest portion of Idiopathic bowel disease?
Crohn’s disease
Ulcerative Colitis
Where is Crohns disease spread limited to?
Any part of GIT
Where is Ulcerative colitis disease spread limited to?
Limited to colon
What is the cause of idiopathic inflammatory bowel disease?
Exaggerated immune response vs gut flora
Genetics
?Defects in the mucosal barrier
What gene mutation is associated with Crohns disease?
NOD2
What gene mutation is associated with Ulerative Colitis?
HLA
How is IBD diagnosed?
Clinical history
Radiograph examination
?pANCA
A positive pANCA test is more likely in which IBD patients?
Ulcerative Colitis
Ulcerative colitis is most common in which age groups?
20-30yrs, 70-80yrs
Ulcerative colitis can often be localised where?
Rectum (proctitis)
Ulcerative colitis more commonly spreads in which way?
Proximal
“backwash ileitis”
What is the histological presentation of Ulcerative Colitis?
NO GRANULOMAS
Inflamed mucosa, crypts
Crypt absesses, disarray
Mucosal atrophy
Atypical flat epithelium caused by UC can lead to what?
Adenomatous change leading to invasive cancer
How does pancolitis effect cancer rates?
If greater than 10 years - it increases the likelihood 20-30x
What is toxic dilation?
Colonic swelling due to gas production in ulcerative colitis
What are the complications of Ulcerative Colitis?
Haemorrhage
Perforation
Toxic dilation
Crohn’s disease is more common in which group
Women
20-30 years
White
Jewish
How do GIT lesions differ in Crohns disease and ulcerative colitis?
Ulcerative colitis - lesions spread out from a point
Crohns disease - lesions skip from point to point
How does Crohns disease effect the GIT?
Granular serosa
Wrapping mesenteric fat
Thickened, fibrotic mesentery
Lumen narrowing, wall thickened
What is the histological presentation of Crohn’s disease?
NON-CASEATING GRANULOMAS Cryptitis/crypt abscesses Deep ulceration 'chain of pearl' inflammation Fibrosis
How do granulomas appear in UC vs CD?
UC - no granulomas
CD - non-caseating granulomas
Long term features of Crohn’s disease
Malabsorption Strictures Fistulas, abscesses Perforation 5x increased cancer risk
How does inflammation appear in UC vs CD?
UC - Mucosa only
CD - Transmural
Ischaemic enteritis is caused by what?
Acute occlusion of 1 of the 3 major enteric vessels
Which part of the LI is most vulnerable to acute ischaemia?
Splenic flexure
Histological presentation of acute intestinal ischaemia
Oedema Interstitial haemorrhage Sloughing necrosis Indistinct nuclei (Initial) absence of inflammation
Which part of the GIT is most commonly effected by radiation colitis?
Rectum (pelvic radiotherapy)
Which cells are targeted by radiation colitis?
Actively dividing cells
Blood vessels
Crypt epithelium
Symptoms of radiation colitis
(Mimics IBD) Anorexia Abdominal cramps Diarrhoea Malabsorption
What is the cause of appendicitis?
Obstruction
Large Bowel Neoplasia can be what?
Dysplasia (adenoma)
Malignancy
What are the main types of adenoma (polyps)?
Tubular
Villous
Tubulovillous
What is the histological presentation of low grade dysplasia?
Increased nuclear no.
Increased nuclear size
Reduced mucin
What is the histological presentation of high grade dysplasia?
Carcinoma in situ
Crowded, irregular
Not YET invasive
The majority of colorectal carcinomas are what?
Adenocarcinoma
What are the risk factors for colorectal adenocarcinoma?
Lifestyle
Family history
IBD (UC & CD)
Genetics (FAP, HNPCC, Peutz-Jeghers)
Pancolitis increases the risk of what?
Colorectal cancer (20-30x)
Why does right sided bowel cancer tend to present late?
More water in bolus on right, so it moves round any blockage more easier than on left (descent)
(Less symptomatic)
How does right side colorectal adenocarcinoma present?
Polypoid Anaemia Vague pain Weakness Obstruction (less severe)
How does left side colorectal adenocarcinoma present?
Annular
Bleeding
Changed bowel habit
Obstruction
