Lower gastrointestinal pathology Flashcards
1
Q
Diverticula of the Large Bowel
A
- Blind ending sac like protrusions from the bowel wall in communication with the bowel lumen
2
Q
Diverticulosis of the Colon
A
- Protrusions of mucosa and submucosa through the bowel wall
- Commonly sigmoid colon
- Relationship with fibre content of diet
- Irregular, uncoordinated peristalsis
- Points of relative weakness in the bowel wall
3
Q
Diverticular Disease definition
A
Small bulges in the large intestine (diverticula) developing and becoming inflamed
4
Q
Acute complications of Diverticular Disease
A
- Diverticulitis/peridiverticular abscess
- bacteria get into bowel wall = left iliac fossa pain
- Perforation leading to diffuse peritonitis
5
Q
Chronic complications of Diverticular Disease
A
- Fistula -abnormal passageway that connects two organs or vessels that do not usually connect
- Diverticular colitis
6
Q
Diverticula with no symptoms =
A
Verticular disease
7
Q
Ulcerative colitis epidemiology
A
- Incidence of UC is increased in urban areas
- UC equally common in males and females
- Risk of ulcerative colitis in 1st degree relative: 8 times
8
Q
Ulcerative colitis clinical presentation
A
- Diarrhoea with urgency/tenesmus
- Constipation 2 %
- Rectal bleeding > 90 %
- Abdominal pain
- Anorexia, Weight loss
- Anaemia
9
Q
Ulcerative colitis complications
A
- UC ONLY affects the large bowel - Inflammation limited to the Mucosa
- Toxic megacolon and perforation
10
Q
Crohn’s disease epidemiology
A
- Incidence same as UC
- CD more common in females 1.3:1
- Risk factors = oral contraceptive, smoking
11
Q
Crohn’s disease clinical presentation
A
- Chronic relapsing disease, affects all levels of GIT from mouth to anus
- Colicky abdominal pain
- MOST likely to be Ileocolic presentation
- Diarrhoea: may be bloody
12
Q
Crohn’s disease complications
A
- Fistula - faeces when urinate
- Stricture -narrowing of the lumen
- Adenocarcinoma - risk of large and small bowel cancer
- Short bowel syndrome -repeated resection
13
Q
Risk factors for colorectal cancer in ulcerative colitis
A
- UC biggest cause of colorectal cancer
- Total or extensive colitis beyond splenic flexure
- Early age of onset; Duration of disease > 8-10 years
14
Q
Ischaemic Colitis definition
A
- Colonic injury secondary to an acute, intermittent or chronic reduction in blood flow
- May be occlusive (obstruction of the arteries) or non-occlusive (reduction of flow)
15
Q
Ischaemic Colitis 3 clinical forms
A
- Transient/evanescent: >80%: lasts for hrs, few days and then gets better
- Chronic segmental ulcerating: ischaemic stricture
- Acute fulminant and gangrenous: Complete necrosis, infarction of bowel wall, surgical emergency
16
Q
Ischaemic Colitis clinical symptoms
A
- Acute onset cramping abdominal pains;
- Urge to defaecate
- Bloody diarrhoea/rectal bleeding
17
Q
Ischaemic Colitis distribution
A
- Most cases of ischaemic colitis affect left colon
- Right colon: 35%
- Water shed area around the splenic flexure, less blood supply therefore greater risk
- Left colon (rectum to splenic flexure): 33%
18
Q
Colorectal Polyps definition
A
- Mucosal protrusion – basically a bump in the mucosal lining
19
Q
Types of colorectal polyps
A
- Solitary or multiple = polyposis
- Pedunculated (with stalk), sessile (no stalk) or flat
- Neoplastic, hamartomatous, inflammatory or reactive
- Benign or malignant
- Epithelial or mesenchymal
20
Q
Hyperplastic polyp
A
- Located in rectum and sigmoid colon
- Small distal HPs have no malignant potential
- right sided “hyperplastic polyps” can give rise to unstable carcinoma
21
Q
Juvenile Polyp
A
- Often spherical and pedunculated - common in children
- Typically occur in rectum and distal colon
- Sporadic polyps have no malignant potential
- Rare genetic condition: juvenile polyposis causes increased risk of colorectal and gastric cancer
22
Q
Peutz-Jeghers Syndrome
A
- Autosomal dominant condition: mutation in STK11 gene on chr 19
- Present clinically in teens/20s with abdominal pain, GI bleeding, anaemia
- Multiple gastro-intestinal tract polyps: predominantly small bowel
23
Q
Neoplastic Polyps
A
- Benign = Adenoma: most common
- Malignant: Carcinoma, Carcinoid, Leiomyosarcoma
24
Q
Adenomas
A
- Benign epithelial tumours; commonly polypoid but may be flat
- Precursor of colorectal cancer: min. 80% cancers develop in already developed adenoma - adenocarcinoma
25
Q
Colorectal cancer definition
A
- 2nd or 3rd commonest cancer causing mortality
- Most bowel cancers (75%) = sporadic
- weak genetic risk
26
Q
Colorectal cancer risk factors
A
- Fat, red meat, calcium inc
- Obesity/ physical activity
- HRT and oral contraceptive
- Pelvic radiation: radiotherapy
- Ulcerative colitis and Crohn’s disease
27
Q
Colorectal cancer types
A
- Adenocarcinoma 95%: gland forming tumours
- Adenosquamous carcinoma
- Squamous cell carcinoma
- Neuroendocrine carcinoma
- Undifferentiated (large cell) carcinoma
- Medullary carcinoma
28
Q
Colorectal cancer spread
A
- Lymphatic metastasis
- Haematogenous metastasis
- Direct invasion of adjacent tissue
- Iatrogenic spread e.g. needle track recurrence or port site recurrence
29
Q
Colorectal cancer protective substances
A
- High fibre + folate diet
- NSAIDS and aspirin decrease risk
30
Q
Familial adenomatous polyposis: FAP
A
- 100% lifetime risk of large bowel cancer
- Associated with multiple benign adenomatous polyps in the colon
- Due to mutation in the APC tumour suppressor gene
31
Q
Lynch Syndrome: HNPCC
A
- 50-70% lifetime risk of large bowel cancer
- Due to mutations in DNA mismatch repair genes
- Two thirds distal to splenic flexure: most common where they occur
32
Q
Colorectal cancer grading
A
- Well differentiated: 10-20%: mimicking normal lining of the bowel
- Moderately well differentiated: 60-80%
- Poorly differentiated: 10-20% - poor prognosis
33
Q
neoplastic cells and colorectal cancer
A
- Neoplastic cells must have invaded through the muscularis mucosae into the submucosa (as can access lymphatics and blood vessels in submucosa)
34
Q
Colorectal cancer key clinical features
A
- Ulceration causes bleeding – fresh and bright red
- If it is in the right side of the colon (more proximal), bleeding is occult (not noticed) – so patients present with anaemia due to chronic bleeding
- Stenosis – pain or emergency
- Weight loss and altered bowel habit
35
Q
Colorectal cancer treatment
A
- Bowel resection – partial
- If near rectum, anal sphincter may need to be removed = colostomy
- Radiotherapy for increased chance of cure
- May give some further chemotherapy
