Week 6 lower Gi tract Flashcards
What are the two types of diverticula?
Acquired –> develop during post natal life
Congenital
What is a diverticula?
Diverticula are blind ending outpouching of the bowel
What is diverticulosis of the colon?
Protrusions of mucosa and submucosa through the bowel wall. Commonly sigmoid colon but can extend into the proximal colon and cecum.
Where in the bowel wall do diverticulosis usually develop?
Located between mesenteric and anti-mesenteric taenia coli
What part of the world is diverticulosis more common in and what type of area ?
Common in developed ( western ) world
Rare in Africa , Asia , S. America
Common in urban cf. rural areas
Changing prevalence in migrant populations
What age group do you see diverticulosis mainly in and does diet have a affect?
Under the age of 40 it is rare but after 40 it becomes more and more common.
Male and females are equal.
However diet plays a part as there is a relationship between fibre content of diet.
Therefore less common in vengetarians due to less fibre
What are the 3 main types of diverticulosis?
Sigmoid diverticulosis
Diverticulosis of the right colon
Giant diverticulum
What is the pathogensis of diverticulum?
There is increased intra lumen pressure casued by Irregular , uncoordinated peristalsis which occurs in the sigmoid colon. Also overlapping semicircular arcs of bowel wall which caused increased pressure in the colon due to the irregular peristalsis.
Causing a point of relative weakness in the bowel wall–> caused by Penetration by nutrient arteries between mesenteric and antimesenteric taenia coli.
Can also be due to age related changes in the connective tissue
How does diverticulosis develop?
Thickening of muscularis propria ( earliest change – “prediverticular disease” )
Elastosis of taeniae coli ( leading to shortening of colon due to contraction of the taenia coli
Redundant mucosal folds and ridges due to the shortening
Sacculation and diverticula
What is the usual clinical features of diverticular disease?
Asymptomatic ( 90 – 99 % )
Cramping abdominal pain
Alternating constipation and diarrhoea
Not to many problem
What percentage of people get chronic or acut complications of diverticular disease?
10-30%
What are the acute complications of diverticulosis?
You get diverticulitis which leads to peridiverticular abscess.
Perforation due to infection of the peritoneal cavity.
Finally can get haemorrhage if the surrounding artery or veins are ulcerated.
What is diverticulitis?
It is inflammation in the diverticula due to ulceration of diverticula lining and invasion of bacteria into the surrounding tissue.
What are the chronic complications of diverticulosis?
Intestinal obstruction ( strictures : 5 – 10 % )
Fistula ( urinary bladder, vagina )
Polypoid prolapsing mucosal folds
Diverticular colitis ( segmental and granulomatous ) –> inflammation in the lining of the bowel –> diarrhoea and rectum bleeding
What is colitis?
Inflammation of the colon usually causing mucosal inflammation but occasionally transmural or predominantly submucosal/muscular
What type of colitis causes inflammation in the transmural?
Crohns disease
What type of colitis causes inflammation in the submucosal/mscular?
Eosinophilic colitis
What can colitis be divided into?
Into acute or chronic
What are the different examples of acute colitis?
Acute infective colitis Antibiotic associated colitis Drug induced colitis Acute ischaemic colitis ( transient or gangrenous ) Acute radiation colitis Neutropenic colitis Phlegmonous colitis
What are the different classification of chronic colitis?
Chronic idiopathic inflammatory bowel disease
Microscopic colitis ( collagenous & lymphocytic )
Ischaemic colitis
Diverticular colitis
Chronic infective colitis eg. amoebic colitis & TB
Diversion colitis
Eosinophilic colitis
Chronic radiation colitis
What are the main 2 types of idiopathic inflammatory bowel diseaese?
ULCERATIVE COLITIS
CROHN’S DISEASE
INDETERMINATE COLITIS ( 10 – 15 % )
What is more common UC or CD?
UC is more common and the incidence is highest in Scandinavia, UK, Northern Europe, USA
What is the peak age incidence of both UC and CD?
Between the age of 20-40 years of age
Is CD or UC more common in males or females?
CD is more common in females
For UC it is equally common in males andd females
Is smoking a risk factor for both UC and CD
For crohns it is a risk factor but it seems to decrease chance of getting UC.
Other than smoking what other factor can potentially increae your risk of IBD?
Oral contraceptive
Is there any familial clustering in IBD?
Yes there is if you have a family member who has UC or CD then the chances of you have either increases dramatically.
What is the clinical presentation of UC?
Diarrhoe with urgency/tenesmus Constipation Rectal bleeding Abdominal plain Anorexia Weight loss Anemia due to the excessive loss from rectal bleeding
What are the complications of UC?
Toxic meacolon and perforation
Haemorhage
Stricture –> rare in UC–> if you see it in UC then sign of cancer
Carcinoma
How is toxic megacolon and perforation caused in UC? How do you treat it?
Toxic megacolon is caused by UC having 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. 40% die when this happens.
Treated with high dose steroids –> If it does not work then need to have the bowel removed before perforation
where does UC typical begin and where does it spread?
Typically starts in the rectum and goes to variable part of the colon –> continous
What are the two histological findings for UC?
Crypt abscess and crypt distortion
What are the clinical features of crohns disease?
Chronic relapsing disease like Uc Affects all levels of GIT from mouth to anus Diarrhoea ( may be bloody ) Colicky abdominal pain Palpable abdominal mass Weight loss / failure to thrive Anorexia Fever Oral ulcers Peri – anal disease anaemia
What is the action of peri-anal disease caused by CD?
Ulcers, strictures, fistula of the anus into the skin/vagina
What parts of the GI tract affected by CD and UC and how does it spread?
CD is patchy and can affect the whole GI tube –> mouth to anus
UC –> affects colon, appendix and terminal ilium but is a continous diseae
What is the most common distruction of crohns disease?
Ileocolic distribution.
Affects the end of the small intestines and the start of the large intestines
What is the defining histological feature of CD? How common is this?
Is the formation of granuloma’s.
Not seen in UC.
However only 60% of patients with CD have granulomas
What are the complications of crohns disease?
Toxic megacolon Perforation Fistula Stricture common unlike in UC. Haemorrhage Carcinoma --> both in large and smal bowel Short bowel syndrome
What is short bowel syndrome?
Caused by repeated resection due to surgery treatment of trying to get rid of the disease. The small bowel becomes so small no longer effective
What is the pathology of UC and CD in terms of whether or not the rectum and terminal ileum is involved?
The rectum is always invovled in UC and 10% of the times terminal ileum involved
The rectum 50% times involved in CD and 30% of the times terminal ileum is involved.
What is the macroscopic appearance of UC and CD?
UC has Granular red mucosa with flat ,undermining ulcers
CD has cobblestone appearance with apthoid and fissuring ulcers
Do you see fistulaes and anal lesions in UC and CD?
There is no spontaneous fistulae in UC but there is a 25% chance of anal lesions
There is a greater than 10% chance of fistulae and 75% chance of anal lesion
What is the affect of Uc and CD on serosa?
No affect in UC but in CD you get serositis?
What type of inflammation is UC and CD?
Uc is mainly mucosal inflammation
While CD is mainly transmural inflammation
What are the affects of CD and UC are on crypts?
In UC there crypt absesses is common and the distrortion is severe
In CD the crypt abscesses is less and not as severe
Is there any presence of granuloma and inflammatory polyps in UC and CD?
In UC there is no granuloma and inflammatory polyps is common.
In CD 60% of cases there is granulomas–> inflammatory polyps are less common.
What affect does inflammatory bowel disease have on the liver?
Fatty change
Granulomas
Primary sclerosing cholangitis
Bile duct carcinoma
What is Primary sclerosing Cholangitis?
It is a chronic liver disease in which the bile ducts inside and outside the liver progressively decrease in size due to inflammation and scarring
What extra skeletal problems can you get with IBD?
Polyarthritis
Sacro-ileitis
Ankylosing spondylitis
What is sacro-ileitis?
Inflammation of the sacroiliac joints of the hip.
What is anyklosing spondylitis?
It is a form of spinal arthritis
What are the Muco-cutaneous extra intestinal manifestations of IBD?
Oral apthoid ulcers
Pyoderma gangrenosum–> skin condition causes painful ulcers
Erythema nodosum–> inflammation of the fat cells under the skin.
What are the Ocular intestinal manifestations of IBD?
Iritis/uveitis
Episcleritis
Retinitis
What are the renal intestinal manifestations of IBD?
Kidney and bladder stones
What are the haematological intestinal manifestations of IBD?
Anaemia
Leucocytosis –> increase number of white cells in the blood
Thrombocytosis –> production of too many platelets
Thrombo-embolic disease –> DVT
What affet can IBD have on systemic system?
Get manifestations of Amyloid and VAsculitis
What is the effect of UC on the development of colorectal cancer?
The longer you have UC the greater the chances of developing cancer. Become a problem after having UC for 10yrs
What are the risk factors of developing colorectal cancer in UC patients?
Early age of onset
Duration of disease > 8-10 years
Total or extensive colitis
Primary Sclerosing Cholangitis
Family History of CRC
Severity and continuous inflammation ( pseudopolyps )
Presence of dysplasia
What are the 4 steps in the development of colorectal cancer in UC?
Inflammed mucosa–> low grade dysplasia –> high grade dysplasia –> colorectal cancer
When is colitis surveillance provided and what is it?
Provided after have UC for 10 yrs.
The Surgeon will colonoscopy a bowel and systemic biopsy –> to try and pick up early stages of cancer
What are colorectal poylps?
A mucosal protusion of the lining of the bowel. Can be solitary or multiple, small or large. It is due to mucosal or submucosal pathology or a lesion deeper in the bowel wall.
What are the different groups of Colorectal polyps?
Neoplastic
Hamartomatous
Inflammatory or reactive
What are the two different group types can neoplastic Colorectal polyps divide into?
Bening or Malignant
Epithelial neoplasm or Mesenchymal Neoplasm
What are the different types of Non-Neoplastic polyps in the colo-rectum? (6)
Hyperplastic polyps –> V. common in large bowel
Hamartomatous polyps
Polyps related to mucosal prolapse
Inflammatory fibroid polyp
Benign lymphoid polyp
Post-inflammatory polyps
What are the two different types of Hamartomatous polyps?
Peutz-jeghers polyps
Juvenile polyps
What is the profile of common Hyperplastic poly?
1-5mm in size
Often multiple
Located in the rectum and sigmoid colon
Distal HP have no malignant potential
When can Hyperplastic polyp have a malignant potential?
Some large right sided ones may give rise to microsatellite unstable carcinoma –> account for 10-15% of all colorectal cancers.
What is the profile of Juvenile Polyp?
Often spherical and pedunculated
10 – 30 mm
Commonest type of polyp in children
Typically occur in rectum & distal colon
Sporadic polyps have no malignant potentia
What types of cancer is Juvenile polyp associated with?
Juvenile polyposis associated with increased risk of colorectal and gastric cancer
What is the cause of Peutz-Jeghers syndrome and what is its clinical presentation?
Autosomal dominant condition ( mutation in STK11 gene on chromosome 19 ).
Present clinically in teens or 20s with abdominal pain ( intussusception ), gastro-intestinal bleeding & anaemia
Muco-cutaneous pigmentation
Multiple gastro-intestinal tract polyps
What is the most common place Peutz-Jeghers syndrome mainly effect?
Small Bowel
Where else can Peutz-Jeghers syndrome effect?
Colon
Rectum
Stomach
Less common
Gallbladder
Urinary bladder
Nasopharynx
What are adenomas?
Benign epithelial tumours
What is adenomas precursor to, what age do you see them and where in the body does it effect?
Precursor of colorectal cancer (at least 80%)
Present 25% - 35% population > 50 years
Evenly distributed around colon BUT larger in recto-sigmoid and caecum
What are the marcoscopic appearance of adenomas?
pedunculated , sessile or “flat”
What are the different histological types of adenomas?
Villous, Tubulo-Villous or Tubular
What are all the benign neoplastic polyps?
Adenoma Lipoma Leiomyoma Haemangioma neurofibroma
What are all the malignant neoplastic polyps?
Carcinoma Carcinoid Leiomyosarcoma GIST Lymphoma Metastatic tumour
How can you predict the malignant change of adenoma?
flat” adenomas
Size ( most malignant polyps > 10 mm )
Villous & Tubulo-Villous
Severe ( high grade ) dysplasia
HNPCC associated adenomas
What is the main cause of colerectal cancer?
Sporadic cause –> 75%
What two conditions cause colorectal cancer
Familial adenomatous polyposis
Hereditary nonpolyposis colorectal cancer
What are the risk factors for colorectal cancer
Diet
Dietary fibre, fat, red meat, folate, calcium
Obesity / Physical Activity Alcohol NSAIDs HRT and oral contraceptives Schistosomiasis Pelvic radiation Ulcerative colitis and Crohns disease
What is FAP and what is the cause?
Autosomal dominat disease caused by the mutation in the APC tumour suppressor gene.
It causes multiple benign adenomatous polyps in the colon and there is 100% lifetime risk of large bowel cancer
What is HNPCC and what is the cause?
It is a autosomal dominant disease with a 50-70% lifetime risk of large bowel cancer.
Due to mutation in the DNA mismatch repair genes.
Does FAP or HNPCC acount for more cases of colorectal cancer?
HNPCC
What other cancers does HNPCC increase the risk of?
Increased risk of endometrial, ovarian, gastric, small bowel, urinary tract and biliary tract cancer
What are are the 6 types of colorectal cancer? Which is the most common?
Adenocarcinoma --> most common Adenosquamous carcinoma Squamous cell carcinoma Neuroendocrine carcinoma & MANEC Undifferentiated carcinoma Medullary carcinoma
How does coloreactal cancer spread?
Direct invasion of adjacent tissues
Lymphatic metastasis ( lymph nodes )
Haematogenous metastasis ( liver & lung )
Transcoelomic ( peritoneal ) metastasis
Iatrogenic spread
What are the two staging mechanisms of colorectal cancer?
Dukes
TNM
What is the N stage in TNM staging of colorectal cancer?
N0 no nodes involved
N1 1 – 3 nodes involved
N2 4 or more nodes involved
What is the duke staging of colorectal cancer?
Stage A : adenocarcinoma confined to the bowel wall with no lymph node metastasis
Stage B : adenocarcinoma invading through the bowel wall with no lymph node metastasis
Stage C : adenocarcinoma with regional lymph node metastasis regardless of depth of invasion
Stage D : distant metastasis presen
