LGIT Path Flashcards
what is diverticula of the large bowel
blind ending sac like proturiosn from the bowel wall to bowel lumen
2 types - true congenital (meckels) all layers of bowel
acquired false pseudo diverticulum - not all bowel walls
what is diverticulosis of the colon and where is it most commonly found
protrusions of mucosa and submucosa through the bowel wall - commonly in the sigmoid colon (between mesenteric and anti-mesenteric tania coli)
what is the pathogenesis of diverticulosis of the colon
increased intra-luminal pressure - irregular uncoordinated peristalsis
hypertrophy and bowel wall thickened
what are some of the presentations patinet would say for diverticular disease of the colon
cramping, alternating constipation and diarrhoea
what are the acute vs chronic clinical presentations of diverticular disease
acute - abscess - left iliac fossa pain = perforation or haemorrhage
chronic - fistula or colitis
what is colitis and its subtypes
inflammation of the colon divided into acute and chronic
what are the differences between acute and chronic colitis
acute - infection or antibiotic associated, drug induced
chronic idiopathic IBD or ischaemic colitis
what are the two types of chronic idiopathic IBD
UC and crohns
what are the incidences and risk factors of IDB’s
CD more common in women but UC equal smoking may be protective in UC but x2 in CD oral contraceptive causes it infections familial or genetic risks from relatives
what are the clinical presentations of UC
diarrhoea, (constipation) rectal bleeding, abdominal pain, weight loss, anaemia
what are the complications of UC
inflammation limited to the colon so could have perforation or toxic megacolon more than 6cm
what structures does UC affect
only the large bowel
what are the clinical presentations of CD
relapsing and affects entire GIT from mouth to anus
diarrhoea, abdominal pain, abdominal mass, weight loos, fever, presence of granulomas
what are the complications of CD
fisulta - sticking to other organs
stricture - narrowing of the lumen
adenocarcinoma
short bowel syndrome - removing too much small bowel = malabsorption
where in the GIT does CD affect
all - mainly ileocolic then small bowel and colonic rarely stomach and duodenum
where else in the body can IBD affect
hepatic - fatty change and granuloma
osteo-articular = joint problems
muco-cutaneous - oral ulcers
ocular - inflammation in the eye
what is the leading cause of colorectal cancer
UC
what are the risk factors of developing CRC in UC patients
early stage onset with family history
extensive UC
PSC - primary sclerosising cholangitis - narrowing of bile duct
what are the four stages of development of CRC in UC
inflamed mucosa
low grade dysplasia
high grade dysplasia
colorectal cancer
what is ischaemic colitis and the 3 forms
colonic injury secondary to acute or chronic reduction in blood flow, occlusive or not
transient
chronic segmental ulcerating - ischaemic stricture
acute fulminant and gangrenous
what would someone present with, with ischameic colitis
acute onset cramping, urge to poo, rectal bleeding - recover after 24hrs
what are the causes of mesenteric ischameia
arterial thrombosis
“ embolism (most common)
non-occlusive ischemia
where is ischaemic colitis most commonly affected and why so
left colon - splenic flexure between transverse and descending colon on left side has watershed area which is at greater risk to ischameia
what are colorectal polyps and what are they causes by and the three structural types
mucosal protrusion
peduncled (with stalk), sessile, no stalk or flat
due to mucosal or submucosal lesion/patholohy
what type of non-neoplastic polyp is the most common as you get older
hyperplastic polyp
what is the most common type of polyp in children and how is it associated with genetics
juvenile polyp
juvenile polyposis = increased risk of CRC and gastric cancer
what is Peutz-jeghers syndrome (PJS), cause and presentation
always inherited - AD mutation in STK11 on chromosome 19
teens with GI bleeding, pain and anaemia
what is the most common type of neoplastic polyp
(benign) adenoma - arising from the epithelium lining the large bowel
what is the precursor to colorectal cancer
benign colon adenoma
what is the 2nd/3rd most common cancer causing mortality
CRC
what are the risk factors of CRC and what are seen as protective
protective - high fibre, folate, aspirin and NSAIDS
risk - fat, red meat, calcium, UC/CD
what are the two types of inherited susceptibility to inherited CRC
FAP - familial adenomatous polyposis CRC - mutation in APC Tumour SG
lynch syndrome (HNPCC) (not as likely to get)
what are the main types of cancer in CRC
adenocarcinoma
what is the most common site of spread of CRC’s
liver and lung (sometimes skin and bone)
what are the two routes of spread of CRC to other organs
haematogenous or lymphatic
what staging is used to grade CRC
dukes or TNM (tumour, nodes, metastasis)
describe the TNM staging
T - 1-4 = how deep into the organ the spread 1 = mucosa 4= all 4 tissue layers of organ
N 0-2 - nodules
M = metastasis present 0 or 1
describe the dukes staging of cancer
a-d determines the chance of cure or more treatment
a = adenocarcinoma confined in small bowel wall 90% survival
B = through bowel wall
c = ADC with lymph metas
d = distant metastasis
