Flashcards in GI Tract 2 (Lower) Deck (75):
What is a 'true' diverticulum?
What is a 'false' or 'pseudo' diverticulum?
Is sigmoid diverticulosis congenital or acquired?
Is diverticulosis of the right colon acquired or congenital?
Can be either?
What is diverticulosis of the colon?
Protrusions of mucosa and submucosa through the bowel wall
Where does diverticulosis of the colon most commonly occur?
Where in the bowel wall are diverticula located?
Located between mesenteric and anti-mesenteric taenia coli ( also between anti-mesenteric t.coli in 50 % cases )
What percentage of diverticula are found in the caecum?
What is the epidemiology of diverticulosis?
- Common in developed ( western ) world
- Rare in Africa , Asia , S. America
- Common in urban cf. rural areas
- Changing prevalence in migrant populations
- Relationship with fibre content of diet
- Increases with age
- Male = female
- Less common in vegetarians
What is the pathology of diverticulosis?
- Increased intra-luminal pressure
- Irregular, uncoordinated peristalsis
- Thickening of muscularis propria ( earliest change – “prediverticular disease” )
- Elastosis of taeniae coli ( leading to shortening of colon )
- Redundant mucosal folds and ridges
- Sacculation and diverticula
What are the clinical features of diverticular disease?
- Asymptomatic ( 90 – 99 % )
- Cramping abdominal pain
- Alternating constipation and diarrhoea
- Acute and chronic complications ( 10 – 30 %)
What are the acute complications of diverticulosis?
- Diverticulitis / peridiverticular abscess ( 20 – 25 % )
- Haemorrhage ( 5 % )
What are the chronic complications of diverticulosis?
- Intestinal obstruction ( strictures : 5 – 10 % )
- Fistula ( urinary bladder, vagina )
- Diverticular colitis ( segmental and granulomatous )
- Polypoid prolapsing mucosal folds
How is colitis classified into acute and chronic?
Acute - days to few weeks
Chronic - months to years
What disease is associated with transmural colitis?
What disease is predominantly associated with submucosal/muscular colitis?
Which types of colitis are acute?
- Acute infective colitis eg. campylobacter, salmonella, CMV
- Antibiotic associated colitis (including PMC)
- Drug induced colitis
- Acute ischaemic colitis ( transient or gangrenous )
- Acute radiation colitis
- Neutropenic colitis
- Phlegmonous colitis
Which types of colitis are chronic?
- 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
Which three diseases fall under the 'idiopathic inflammatory bowel disease' umbrella?
Indeterminate colitis (10-15%)
What is the epidemiology of IBD?
- UC 5 – 15 cases per 100,000 p.a.
- CD 5 – 10 cases per 100,000 p.a.
- Incidence highest in Scandinavia, UK, Northern Europe, USA
- Lower in Japan, Southern Europe, Africa
- Peak age incidence 20 – 40 years of age
- CD more common in females 1.3 : 1
- UC equally common in males and females
- Incidence of UC is increased in urban areas
For which IBD condition is smoking a risk factor and for which does it have a protective effect?
UC - protective
CD - risk factor
Give some other risk factors for IBD.
What is the risk of UC in the 1st degree relative of someone with UC?
What is the risk of CD in the 1st degree relative of someone with UC?
What is the risk of UC in the first degree relative of someone with CD?
What is the risk of CD in the first degree relative of someone with CD?
What is the clinical presentation of UC?
- Diarrhoea ( > 66 % ) with urgency/tenesmus
- Constipation ( 2 % )
- Rectal bleeding ( > 90 % )
- Abdominal pain ( 30 – 60 % )
- Weight loss ( 15 – 40 % )
What are the possible complications of UC?
- Toxic megacolon
- Stricture (rare)
What are the clinical features of CD?
- Chronic relapsing disease
- Affects all levels of GIT from mouth to anus
- Diarrhoea ( may be bloody )
- Colicky abdominal pain
- Palpable abdominal mass
- Weight loss / failure to thrive
- Oral ulcers
- Peri – anal disease
What is the distribution of CD across the GI tract epidemiologically speaking?
Ileocolic 30 – 55 %
Small bowel 25 – 35 %
Colonic 15 – 25 %
Peri-anal / ano-rectal 2 – 3 %
Gastro – duodenal 1 – 2 %
What are the possible complications of CD?
- Toxic megacolon
- Stricture ( common )
- Short bowel syndrome (repeated resection)
What is the difference in how CD and UC affect the GI tract?
UC - affects colon, appendix and terminal ileum
CD - affects all parts of the digestive tract
How do UC and CD lesions differ?
UC - continuous disease
CD - skip lesions
What is the difference in rectum involvement between UC and CD?
UC - rectum always involved
CD - rectum normal in 50%
What is the difference in terminal ileum involvement between CD and UC?
UC - terminal ileum involved in 10%
CD - terminal ileum involved in 30%
What is the difference in macroscopic appearance between UC and CD?
UC - granular red mucosa with flat, undermining ulcers
CD - cobblestone appearance with apthoid and fissuring ulcers
What is the difference in the effect on the serosa in UC and CD?
UC - normal serosa
CD - Serositis (fat wrapping)
How common are strictures in CD and UC?
UC - strictures rare
CD - strictures common
What is the difference in the incidence on spontaneous fistulae in UC and CD?
UC - no spontaneous fistulae
CD - fistulae in > 10%
How common are anal lesions in UC and CD?
UC - anal lesions in 25%
CD - anal lesions in 75%
What is the difference in inflammation between UC and CD?
UC - mainly mucosal inflammation
CD - transmural
How common are crypt abscesses in UC and CD?
UC - common
CD - less common
How severe is crypt distortion in UC vs CD?
UC - crypt distortion severe
CD - crypt distortion less severe?
Are granulomas present in UC or CD?
Only present in CD - sarcoid- like granulomas present in around 60%.
How common are inflammatory polyps in UC vs CD?
UC - inflammatory polyps common
CD - inflammatory polyps less common
What are the hepatic manifestations of IBD?
- Fatty change
- Bile duct carcinoma
What are the skeletal manifestations of IBD?
- Ankylosing spondylitis
What are the muco-cutaneous manifestations of IBD?
- Oral apthoid ulcers
- Pyoderma gangrenosum
- Erythema nodosum
What are the ocular manifestations of IBD?
What are the renal manifestations of IBD?
- Kidney and bladder stones
What are the haematological manifestations of IBD?
- Thrombo-embolic disease
What are the systemic manifestations of IBD?
What is the overall prevalence of colorectal cancer (CRC) in UC?
Overall - 3.7%
In pancolitis - 5.4%
At 10 years - 2%
At 20 years - 8%
At 30 years 18%
What are the risk factors for CRC in UC?
- Early age of onset
- Duration of disease > 8-10 years
- Total or extensive colitis
- Family History of CRC
- ? Severity of inflammation ( pseudopolyps )
- Presence of dysplasia
What is a colorectal polyp?
- A “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
What are the different types of polyps?
What are the different types of non-neoplastic polyps that can be found in the colorectum?
- Hyperplastic polyps (? Reactive ? Neoplastic)
- Hamartomatous polyps (Peutz-jeghers polyps, Juvenile polyps)
- Polyps related to mucosal prolapse (inflammatory cloacogenic polyp, inflammatory cap polyp & inflammatory myoglandular polyp)
- Post-inflammatory polyps (“pseudopolyps”)
- Inflammatory fibroid polyp
- Benign lymphoid polyp
What are hyperplastic polyps?
- 1 – 5 mm in size
- often multiple
- located in rectum and sigmoid colon
- small distal HPs have NO malignant potential
What kind of cancer might large, right-sided "hyperplastic polyps" give rise to?
Microsatellite unstable carcinoma (10% - 15% all colorectal cancer)
What is a 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
What is juvenile polyposis a risk factor for?
Colorectal and gastric cancer
What is Peutz- Jeghers Syndrome?
- Autosomal dominant condition ( mutation in STK11 gene on chromosome 19 )
- Prevalence : 1 in 50,000 – 1 in 120,000 births
- Present clinically in teens or 20s with abdominal pain (intussusception), gastro-intestinal bleeding & anaemia
- Multiple gastro-intestinal tract polyps (predominantly small bowel)
- Muco-cutaneous pigmentation (1 – 5mm macules peri-oral , lips , buccal mucosa , fingers and toes)
What are the benign neoplastic polyps?
What are the malignant neoplastic polyps?
- Metastatic tumour
What are adenomas?
- Benign epithelial tumours
- Commonly polypoid but may be “flat”
- Precursor of colorectal cancer (at least 80%)
- Present 25% - 35% population > 50 years
- Multiple in 20 – 30 % patients
- Evenly distributed around colon BUT larger in recto-sigmoid and caecum
What are the risk factors for colorectal cancer?
- Diet - (Dietary fibre, fat, red meat, folate, calcium)
- Obesity / Physical Activity
- HRT and oral contraceptives
- Pelvic radiation
- Ulcerative colitis and Crohns disease
What is familial adenomatous polyposis?
- Associated with multiple benign adenomatous polyps in the colon
- Due to a mutation in the APC tumour suppressor gene
What is hereditary non-polyposis colorectal cancer?
- Increased risk of endometrial, ovarian, gastric, small bowel, urinary tract and biliary tract cancer
- Due to mutations in DNA mismatch repair genes
- 1 – 2 % all colorectal cancer
- Autosomal dominant
- 50 - 70 % lifetime risk of large bowel cancer
What are the different types of colorectal cancer?
- Adenocarcinoma ( > 95 % ) - (Mucinous adenocarcinoma ( 10 – 20 % ))
- Adenosquamous carcinoma
- Squamous cell carcinoma
- Neuroendocrine carcinoma & MANEC (small cell anaplastic ca ; well diffn EC ca)
- Undifferentiated ( large cell ) carcinoma
- Medullary carcinoma
What is the typical spread of colorectal cancer?
- Direct invasion of adjacent tissues
- Lymphatic metastasis (lymph nodes)
- Haematogenous metastasis (liver & lung)
- Transcoelomic (peritoneal) metastasis
- Iatrogenic spread (eg. needle track recurrence port site recurrence)
What are the two ways of staging colorectal cancer?
What does the T from TNM stand for?
T: size or direct extent of the primary tumor
- Tx: tumor cannot be evaluated
- T is: carcinoma in situ
- T0: no signs of tumor
- T1, T2, T3, T4: size and/or extension of the primary tumor
What does the N from TNM stand from?
N: degree of spread to regional lymph nodes
- Nx: lymph nodes cannot be evaluated
- N0: tumor cells absent from regional lymph nodes
- N1: regional lymph node metastasis present; (at some sites: tumor spread to closest or small number of regional lymph nodes)
- N2: tumor spread to an extent between N1 and N3 (N2 is not used at all sites)
- N3: tumor spread to more distant or numerous regional lymph nodes (N3 is not used at all sites)
What does the M from TNM stand for?
M: presence of distant metastasis
- M0: no distant metastasis
- M1: metastasis to distant organs (beyond regional lymph nodes)