gastrointestinal_week_4_20190518174147 Flashcards
what is a polyp
protrusion above an epithelial surface - it is a tumour (swelling)
what is malignant epithelial polyps (majority of polyps)
polypod - adenocarcinomas carcinoid polyps
what is majority of benign epithelial polyps
neoplastic - adenoma (do not metastasise)
what is different macroscopic views of polyps
pedunculated (hanging)sessile (slightly raised)flat (completely flat)
why would pedunculated be the polyp youd want
its easier to remove
what does the actual polyp look like under macroscope
irregular surface, long stalk
what does polyp look like histopathologically
dysplastic epithelial lining
what is the different architecture variables of adenoma polyps
tubullovillous, tubular or villousBUT all are dysplastic
what is the consequence of adenomas
they are precursors of cororectal carcinomas
why must all adenomas be removed
because they are all premalignant, either done endoscopically or surgically
what is the pathology of a large bowel tumour
moderately differentiated dirty necrosis patterntumour is invasive through muscularis propia
what is the staging of colorectal carcinoma
dukes A - confined by muscularis propia dukes B - through muscularis propia dukes C - metastatic to lymph nodes
how do patients present with left sided (rectum, sigmoid, descending) colorectal carcinoma - 75%
blood PR, altered bowel habit, obstruction
how do patients present with right sided (caecum, ascending) colorectal carcinoma - 25%
anaemia, weight loss
what is pathology of cororectal carcinoma
varied gross appearance (polypoid, stricturing, ulcerating)typical histopathological appearance (adenocarcinomas)clinical stuff in other lecture
what are the three ways colorectal carcinoma can kill you
local invasion (mesorectum, peritoneum, other organs)lymphatic spread (mesenteric nodes)haematogenous (liver via portal venous system, distant sites)
what are the different kinds of inherited cancer syndromes
heriditary non polyposis coli (HNPCC) - <100 polypsfamilial adenomatous polyposis (FAP) - >100 polypsonly 10% is inherited
what is characteristics of HNPCC
late onset, autosomal dominant, defect in DNA mismatch repair, inherited mutation in MLH-1, MSH-2, PMS-1, MSH-6
what is characteristics of FAP
early onset, autosomal dominant, defect in tumour supression, inherited mutation in FAP gene
how does HNPCC present
right sided tumours, mucinous tumours, crohns like inflammatory response, associated with gastric and endometrial carcinoma
how does FAP present
throughout colon, adenocarcinoma, no specific inflammatory response, associated with desmoid tumours and thyroid carcinoma
the longitudinal smooth muscle layer in caecum and colon is dividd into three strands - what is this called
taeniae coli - it encircles rectum and anal canal smooth muscle is thickened at internal anal sphincter which is surrounded by skeletal muscle of external anal sphincter
the activity of taeniae coli and circular muscle layers in colon causes sac like budges - what is this called
haustra
caecum normally receives material (undigestible residues etc) from terminal ileum - what permits the entry of this
gastroileal reflex in response to gastrin and CKK through one way ileocaecal valve
how does the ileocaecal valve work
maintain positive resting pressurerelaxing in response to distension of duodenum contracting in response to distension of ascending colon
what causes appendicitis
when appendiceal office that connects lymphoid tissue to distal caecum being obstructed by faecalith
what are common benign condition
crohns colitis and ulcerative colitis, diverticular disease, functional disorders
what are less common benign conditions
colonic volvulus, colonic andiodysplasia, ischaemic colitis, pseudo-obstruction
what is diverticular disease
mucosal herniation through muscle coat effects sigmoid colon, low fibre intake, incidental finding is it diverticulosis or diverticulitis?
how is diverticulosis diagnosed
clinical barium enema sigmoidoscopy
what is the clinical features of diverticulitis
LIF pain/tendernessseptic altered bowel habit
what are the complications of diverticular disease
pericolic abscess, perforation, haemorrhage, fistula (abnormal connection between 2 epithelial surfaces), stricture
what is treatment of uncomplicated diverticulitis
some IV oral antibiotics
what is treatment of complex diverticulitis
percutaneous drainage hartmanns procedure laparoscopic lavage and drainage primary resection/anastomosis
what are causes of acute and chronic colitis
infective colitis, ulcerative colitis, crohns colitis, ischaemic colitis
what is symptoms of acute and chronic colitis
diarrhoea +/- blood abdominal cramps dehydration sepsis weight loss, anaemia (chronic)
how can colitis be diagnosed
plain X-ray sigmoidoscopy + biopsy stool culturesbarium enema (dont really do this anymore)
what is treatment of ulcerative colitis / crohns colitis
IV fluids IV steroids - once infective/ischaemic colitis ruled out GI rest
what happens if patient doesnt settle after treatment
rescue medial therapy surgery
what is characteristics of ischaemic colitis
in elderly - effects arteriescan be acute or chronic occlusion of inferior mesenteric artery
what is characteristics of colonic angiodysplasia
submucosal lakes of blood obscure cause of rectal bleeding usually right side of colon
how is colonic angiodysplasia diagnosed
angiographycolonoscopy injection or surgical resection
how is colonic angiodysplasia treated
embolisationendoscopic ablationsurgical resection
what are causes of large bowel obstruction
colorectal cancer, benign stricture, volvulus
what is the usual treatment of large bowel obstruction
resuscitate, operate, stenting
signs of large bowel obstruction
constipation, vomiting, abdominal distension, pain
what causes sigmoid volvulus
bowel twists on mesentery may become gangrenous
how can sigmoid volvulus be diagnosed
plain X-ray abdo rectal contrast
what is treatment of sigmoid volvulus
flatus tube, surgical resection
what is pseudo-obstruction
no real mechanical obstructionin elderly/debilitated hypoxia
what are functional bowel disorders
chronic constipation - if young check thyroid
other notes on document
other notes on document
what causes antibiotic induced pseudomembranous colitis
patients on broad spectrum - c.diff toxin A and B attack endothelium and epithelium massive diarrhoea and bleeding
how to treat this
flagyl/vancomycin
what is collagenous colitis
thickened basement membrane disease is patchy no chronic architectural changes
what to look for in clinical history in collagenous colitis
watery diarrhoea, normal endoscopy, drug history etc
what is lymphocytic colitis
no chronic architectural changes in crypts intraepithelial lymphocytes raised but no thickening of BM
what is radiation colitis
telangectasia (widened venules)bizarre stromal cells
what is infective colitis
infectionrarely drugs, ischaemia, endoscopy etc busy epithelial but no crypt irregularity
