Lower GI pathology

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  • Created by: hadar
  • Created on: 28-02-18 12:47
What is a diverticula?
blind ending sac-like protrusion from the bowel wall in communication with the bowel lumen -- can be true/congenital or false/pseudo/aquired
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What is diverticulosis of the colon?
Protrusions of mucosa and submucosa through the bowel wall Commonly sigmoid colon Located between mesenteric and anti-mesenteric taenia coli ( also between anti-mesenteric t.coli in 50 % cases ) Less commonly extend into proximal colon
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What is the pathogenesis of diverticulosis of colon? (2)
1) increased intra-luminal pressure- irregular, uncoordinated peristalsis, overlapping semicircular arcs of bowel wall 2)points of relative weakness in bowel wall- penetration by nutrient arteries, age related connective tissue changes
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What are the clinical features of diverticular disease?
1)asymptomatic 2)cramping abdominal pain 3)alternating constipation and diarrhoea
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What acute complications can you get with diverticular disease?
1)diverticulitis/ peridiverticular abscess 2)perforation 3)haemorrhage
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What chronic complications can you get with diverticular disease?
1)intestinal obstruction- strictures 2)fistula- urinary bladder, vagina 3)diverticular colitis- segmental and granulomatous 4)polypoid prolapsing mucosal folds
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Define colitis
inflammation of the colon- usually mucosal inflammation but occasionally transmural ( eg. crohns disease ) or predominantly submucosal/muscular ( eg. eosinophilic colitis ) divided into acute ( days to a few weeks ) and chronic ( months to years )
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What are the causes of acute colitis? (7)
Acute infective colitis-campylobacter, shigella, salmonella, CMV Antibiotic associated colitis (including PMC) Drug induced colitis Acute ischaemic colitis (transient/gangrenous) Acute radiation colitis Neutropenic colitis Phlegmonous colitis
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What are the causes of chronic colitis? (8)
Chronic idiopathic inflammatory bowel disease- Ischaemic colitis- Diverticular colitis-Microscopic colitis (collagenous & lymphocytic)-Chronic infective colitis eg.amoebic colitis+ TB Diversion colitis- Eosinophilic colitis- Chronic radiation colitis
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What are the 3 diseases in the category of idiopathic inflammatory bowel disease?
1) ulcerative colitis 2)crohn's disease 3)unclassified and indeterminate colitis
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What is the clinical presentation of ulcerative colitis?
1)diarrhoea with urgency/tenesmus 2)constipation 3)rectal bleeding 4)abdominal pain 5)anorexia 6)weight loss 7)anaemia
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What complications could you have with ulcerative colitis?
1)toxic megacolon and perforation 2)haemorrhage 3)stricture (rare) 4)carcinoma
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What are the clinical features of crohns disease?
1)chronic relapsing disease 2)all GI-from mouth to anus 3)diarrhoea 4)colicky abdominal pain 5)palpable abdominal mass 6)weight loss/ failure to thrive 7)anorexia 8)fever 9)oral ulcers 10)peri-anal disease 11)anaemia
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Whats the distribution of crohns disease?
Ileocolic 30 – 55 % Small bowel 25 – 35 % Colonic 15 – 25 % Peri-anal / ano-rectal 2 – 3 % Gastro – duodenal 1 – 2 %
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What complications can you get with crohns disease?
1)toxic megacolon 2)perforation 3)fistula 4)stricture(common) 5)haemorrhage 6)carcinoma 7)short bowel syndrome
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What are the extra-intestinal manifestations of IBD?
Hepatic-fatty change & granulomas/ PSC & bile duct carcinoma Osteo-articular-Polyarthritis/ Sacro-ileitis & Ankylosing Spondylitis Muco-cutaneous-oral ulcers/pyoderma gangrenosum & erythema nodosum Ocular-Uveitis & retinitis
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What are the systemic extra-intestinal manifestations of IBD?
Systemic= Amyloidosis/ Thrombo-embolic disease
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Wha are the risk factors for CRC in UC? (7)
1)Early age of onset 2)Duration of disease > 8-10 years 3)Total or extensive colitis ( beyond splenic flexure ) 4)PSC 5)Family History of CRC 6)Severity of inflammation ( pseudopolyps ) 7)Presence of dysplasia
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What is ischaemic colitis?
colonic injury secondary to an acute, intermittent or chronic reduction in blood flow” may be occlusive or non-occlusive ( NOMI ) usually multifactorial and associated with other vascular diseases
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What are the 3 clinical forms of ischaemic colitis?
1) transient or “evanescent” ( > 80% ) 2) chronic segmental ulcerating ( ischaemic stricture ) 3)acute fulminant & gangrenous ( 10-20% )
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What are the 3 causes of mesenteric ischaemia?
1) arterial embolism 2)arterial thrombosis 3)non-occlusive mesenteric ischaemia
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Where do most cases of ischaemic colitis affect?
Left colon (splenic flexure area) (rare for rectum to be affected due to good blood supply)
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What is a colorectal polyp?
a mucosal protrusion
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Describe the possible characteristic of a colorectal polyp
1)solitary/ multiple 2)pedunculate/ sessile/ flat 3)small/large
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What are the 4 types of colorectal polyp?
1)neoplastic 2)hamartomatous 3)inflammatory 4)reactive --- can be benign/malignant --- epithelial/mesenchymal
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Describe hyper plastic polyp
Common 1 – 5 mm in size often multiple located in rectum and sigmoid colon small distal HPs have NO malignant potential
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Describe 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 potential
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What is peutz-jeghers syndrome?
autosomal dominant condition- mutation in STK11 gene chr19
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How does peutz-jeghers syndrome present?
teens with abdominal pain ( intussusception ), gastro-intestinal bleeding & anaemia ; increased risk of cancer - multiple gastro-intestinal tract polyps (mainly small bowel) and much-cutaneous pigmentation
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Name 6 benhin neoplastic polyps
1)adenoma 2)lipoma 3)leiomyoma 4)haemangioma 5)neurofibroma 6)ganglioneuroma
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Name 6 malignant neoplastic polyps
1)carcinoma 2)carcinoid 3)leiomyosarcoma 4)GIST 5)lymphoma 6)metastatic tumour
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What are adenomas?
benign epithelial tumours- commonly polypoid
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What are the risk factors for colorectal cancer?
1)diet 2)obestiy/physical activity 3)alcohol 4)NSAIDs/aspirin 5)HRT/oral contraceptive 6)schistosomiasis 7)pelvic radiation 8)UC/crohns disease
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What is FAP?
familial adenomatous polyposis- autosomal dominant inheritance - associated with multiple benign adenomatous polyps in colon due to APC tumour suppressor gene mutation
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What is lynch syndrome?
autosomal dominant - mutation in DNA mismatch repair genes
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What does lynch syndrome increase you chance of having (cancer)?
Increased risk of endometrial, ovarian, gastric, small bowel, urinary tract and biliary tract cancer
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What is the most common type of colorectal cancer?
adenocarcinoma >95%
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How can colorectal cancer spread?
1)Direct invasion of adjacent tissues 2)Lymphatic metastasis ( lymph nodes )3)Haematogenous metastasis ( liver & lung ) 4)Transcoelomic ( peritoneal ) metastasis 5)Iatrogenic spread
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How is colorectal cancer staged?
1)Dukes stage 2)TNM stage
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Card 2

Front

What is diverticulosis of the colon?

Back

Protrusions of mucosa and submucosa through the bowel wall Commonly sigmoid colon Located between mesenteric and anti-mesenteric taenia coli ( also between anti-mesenteric t.coli in 50 % cases ) Less commonly extend into proximal colon

Card 3

Front

What is the pathogenesis of diverticulosis of colon? (2)

Back

Preview of the front of card 3

Card 4

Front

What are the clinical features of diverticular disease?

Back

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Card 5

Front

What acute complications can you get with diverticular disease?

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