Lower GI diseases Flashcards
What are the 2 kinds of diverticula?
Congenital diverticula
Acquired diverticula
What is diverticulosis of the colon?
Protrusions of mucosa and submucosa through the bowel wall - commonly the sigmoid colon
less commonly extending into the proximal colon
Where in the bowel wall do the diverticula tend to be located?
Between mesenteric and anti-mesenteric taenia coli - (also between the 2 anti mesenteric taenia coli in 50% of cases)
Name 3 kinds of diverticulosis, do they involved congenital or aquired diverticula?
1) Sigmoid diverticulosis - acquired diverticula
2) Diverticulosis of the right colon - acquired and congenital diverticula
3) Giant diverticulum
Which part of the world is diverticulosis most common in?
The developed/western world - relationship to dietary fibre
Rare in Asia, South America and Africa
How does the incidence of diverticulosis relate to age?
Incidence increases with age
What is the pathogenesis of diverticulosis?
- Increased intraluminal pressure due to irregular, uncoordinated peristalsis and overlapping (valve like) semicircular arcs of bowel wall
- Protrusion through points of relative weakness in the bowel wall - eg. points of penetration by nutrient arteries, between mesenteric and anti-mesenteric taenia coli and age related changes in connective tissue can also lead to a weaker wall
What 4 steps occur for diverticula to develop?
1) Thickening of muscularis propria (earliest change - pre diverticula disease)
2) Elastosis of taenia coli - leading to shortening of colon
3) Redundant mucosal folds and ridges
4) Sacculation and diverticula form
What are the clinical features of diverticulosis?
90-99% will be asymptomatic
Some will get cramps
alternating constipation
and
diarrhoea
Also get acute and chronic complications
What are the 3 main acute complications of diverticulosis?
1) Diverticulitis/ peridiverticular abscess (in the peri colonic fat)
2) Perforation
3) Haemorrhage (bleeding from rectum)
What are the 4 main chronic complications of diverticulosis?
1) Intestinal obstruction (strictures)
2) Fistula (urinary bladder, vagina)
3) Diverticular colitis (segmental and granulomatous)
4) Polypoid prolapsing mucosal folds
What is colitis?
Inflammation of the colon - usually mucosal inflammation but can be transmural (eg. CD)
Can be caused by drugs, CMV, Shigella and other bacteria
What are the 7 types of acute colitis?
1) Acute infective colitis (campylobacter, salmonella, CMV)
2) Abx associated colitis
3) Drug induced colitis
4) Acute ischaemic colitis
5) Neutropenic colitis
6) Phlegmonous colitis
What are the 8 kinds of chronic colitis?
1) Chronic idiopathic IBD
2) Microscopic colitis (collagenous and lymphocytic)
3) Ischaemic colitis
4) Diverticular colitis
5) Chronic infective colitis (amoebic colitis & TB)
6) Diversion colitis
7) Eosinophilic colitis
8) Chronic radiation colitis
What are the 3 types of chronic idiopathic Inflammatory Bowel Disease?
1) Crohn’s disease
2) Ulcerative colitis
3) Indeterminate colitis
In which parts of the world is IBD more common?
Northern Europe, UK and USA
At which age, gender is IBD most common?
Between 20-40 years
CD more common in females
UC equal in both males and females
Is smoking a risk factor for both Chron’s D and Ulcerative C?
Increases the risk of Chron’s D
Actually has a protective affect against Ulcerative Colitis
Other than smoking name a risk factor for both UC and CD?
Oral contraceptive
Does IBD show familial clustering?
Yes - its likely the genes involved overlap as people having a family member with UC increases your risk of CD and visa versa
What are the 7 most common components of the clinical presentation of UC?
1) Diarrhoea
2) Constipation
3) Rectal bleeding
4) Abdo pain
5) Anorexia
6) Weight loss
7) Anaemia
8) Tends to only affect the rectum and sigmoid colon
How does UC lead to toxicmegacolon?
UC has a remitting and relaxing course - occasionally get a very severe flare up that badly damages the colon wall, particularly affecting the transverse colon, get a severely inflamed and dilated transverse colon, gas can build up, leading to perforation
What are the 4 main complications of UC?
1) Toxic megacolon and perforation
2) Haemorrhage
3) Stricture (rare)
4) Carcinoma
What are the 10 clinical features of Chrons disease?
1) Affects all the levels of GIT from mouth to anus (skip lesions)
2) Diarrhoea (may be bloody)
3) Colicky abdo pain
4) Palpable abdo mass
5) Weight loss/ failure to thrive
6) Anorexia
7) Fever
8) Oral ulcers
9) Peri-anal disease (abscesses around anus)
10) Anaemia
What is the most common distribution of Chrons Disease?
Ileocolic distribution
30-55%
What are the 7 main complications of CD?
1) Toxic megacolon
2) Perforation
3) Fistula
4) Stricture (common)
5) Haemorrhage
6) Carcinoma
7) Short bowel syndrome (repeated resection)
What are the differences between UC and CD in terms of a) sights b) pattern c) rectum involvement d) terminal ileum involvement?
In UC: a) Affects colon, appendix and terminal ileum b) Continuous c) Rectum always involved d) Terminal ileum involved in 10% In CD: a) affects all parts of GIT b) skip lesions c) rectum normal in 50% d) terminal ileum involved in 30%
What is the difference between UC and CD in terms of macroscopic appearance?
CD - cobblestone appearance with apthoid ulcers and fissuring ulcers
UC - granular, red mucosa with flat, undermining ulcers
How is the serosa affected in UC and CD?
CD - serositis (fat wrapping)
UC - normal serosa