Small Bowel and Colorectal Pathology Flashcards
what is diverticulae disease?
little outpouchings of the colon caused by the strain of chronic constipation
compare an obstruction in proximal small bowel to distal small bowel- in terms of vomiting and distention?
proximal small bowel: vomiting, no distention
distal small bowl: no vomiting, gross distension
what type of pain does a patient feel with small bowel obstruction usually?
central colicky pain
what are the 3 main causes of small bowel obstruction?
adhesions
hernia
cancer
(+other causes eg crohn’s stricture, bezoar)
how do you treat a small bowel obstruction if there is no strangulation involved?
(excluding hernia)
IV fluids + nasogastric suctoin (‘drip and suck’)
operate if no resolution within 24-48 hours
how do you treat a small bowel obstruction if there is strangulation involved?
resuscitate
antibiotics
early surgery
what are the 3 main signs a small bowel obstruction has become stangulated?
constant pain
signs of sepsis
shock
what is gall stone ileus?
a rare cause of small bowel obstruction:
large gallstones migrate through fistulas into the small bowel and become lodged causing an obstruction
where is the commonest site for Crohns disease lesions?
terminal ileum
what is is called when Crohn’s disease affects the large bowel?
crohn’s colitis
how do you diagnose suspected Crohn’s disease?
barium enema
gastroscopy/colonoscopy
which is more associated with perianal disease- UC or crohns?
crohns disease
what is the basis of medical therapy for Crohn’s disease?
steroids and immunosuppression
why might a patient undertake surgery for Crohn’s disease?
for mechanical complications
usually small bowel resection
what is the pain patients usually present with small bowel ischaemia/infarction?
severe, poorly localised pain
what is the treatment for small bowel ischaemia and infarction?
surgery to revascularise intestine and resection of gangrenous intestine
what is meckers diverticulum?
a congenital diverticulum formed from a remnant of the vitelline duct
what is ileus of the small bowl?
the small bowel has stopped working but there is no mechanical obstruction
when do patients tend to feel the pain from chronic ischaemia of the SMA?
post-prandially
why is colonic infarction unlikely?
marginal artery of drummond provides an anastomoses
where does meckels diverticulum occur?
usually 2 feet from ileocaecal valve
when does meckels diverticulum usually present?
although remember most are asymptomatic
before 2 years of age
what type of diet is diverticular disease related to?
low fibre diet
what are the 5 main complications of diverticular disease?
inflammation rupture abscess fistula massive bleeding
what are the 6 factors that can cause ischaemia of the large bowel?
CVS disease Atrial Fibrillation Embolus Atherosclerosis of mesenteric vessels Shock Vasculitis
what are the 3 main complications of ischaemic colitis?
massive bleeding
rupture
stricture
what is causes pseudomembranous colitis?
C. dif
what is a factor for getting clostridium difficile?
broad spectrum antibiotics
ciprofloxacin, ceftriaxone, clindamycin, co-amoxiclav especiially
what does pseudomembranous colitis cause?
massive diarrhoea and bleeding
what is collagenous colitis?
a patchy, inflammatory condition of the bowl where the basement membrane becomes thickened
what are the main symptoms of IBS?
abdominal pain bloating change in bowel habit (diarrhoea, consti[ation, mixed) urgency nocturia
what is the F:M ratio of IBS?
2 : 1
what are the main pathophysiological features of IBS?
disturbed GI motility
visceral hypersensitiviry
what type of GI distrurbance occurs in IBS?
high-amplitude propagating contractions
exaggerated gastro-colic reflex
what are the 2 mechanisms of visceral hypersensitivity in IBS patients?
peripheral sensations:
up-regulation of sensitivity of nociceptor terminals
central sensations:
increased sensitivity of spinal neurones
what are nociceptor terminals responsible for?
sensation of pain
what might cause up-regulation of sensitivity of nociceptor terminals?
inflammatory mediators
eg gastroenteritis trigger
what is the Rome III criteria for IBS?
recurrent abdo pain/discomfort for at least 3 days per months for 3 months
+2 out of:
-improvement of pain with defecation
-onset associated with change in stool frequency
-onset associated with change in stool form
what is nocturia- and why does IBS cause it?
poor sleep
IBS sufferers don’t actually get up to go to the toilet at night they just can’t sleep because they are worried about their stomach
what 5 conditions have associations with IBS?
fibromyalgia chronic fatigue syndrome temporomandibular joint dysfunction chronic elvic pain psychiatric problems
when a patient presents with possible IBS what are the alarm features that it is something more sinister?
age >50 short duration of symptoms woken from sleep to run to toilet rectal bleeding weight loss anaemia FH of colorectal cancer recent antibiotics
what does waking up from sleep to run to the toilet suggest? (rather than IBS)
IBD
why in some rare cases may IBS give you weight loss or anaemia?
the diet they are on is too strict
what investigations must you carry out for a patient with suspected IBS?
FBC ESR CRP antibody testing for anti-TTG (lower GI tests if >50 or strong FH of colorectal cancer)
what is the diet treatment of IBS?
regular meal times
reduce or increase fibre
what is the drug treatment of IBS?
stop opiate analgesia
anti-diarrhoeals
anti-spasmodics
anti-depressants
why must yous top opiates in a patient with IBS?
because even though opiates have anti-diarrhoea effects they have a long term effect on bowel function: opiate/narcotic bowel syndrome
- worsening pain
- reliance on opiates
why are anti-depressants used in IBS?
reduces visceral hypersensitivity
compare doses of anti-depressants used for IBS to doses used for depression?
much lower doses for IBS
what anti-depressant is used most commonly in IS?
amitriptyline
what forms the outpouchings within the colon in diverticular disease?
mucosal herniation through muscle coat
where within the colon is diverticular disease most common?
sigmoid colon
what are the 3 main clinical features of diverticulitis?
left iliac fossa pain/tenderness
septic
altered bowel habit
what investigations can you use to diagnose diverticulitis?
barium enema
sigmoidoscopy
what is the treatment for diverticulitis?
IV fluids
bowel rest
IV antibiotics
surgery if no improvement or complications
what are the 5 main complications of diverticular disease?
pericolic abscess perforation haemorrhage fistula stricture
where are the 2 surgical operations used for diverticular disease?
hartmanns procedure
primary resection/anastomosis
what is hartmanns procedure?
surgical resection of the recto sigmoid colon and formation of an end colostomy
what are the 4 main causes of acute/chronic colitis?
infective colitis
ulcerative colitis
crohns colitis
ischaemic colitis
what are the 6 main symptoms of acute/chronic colitis?
diarrhoea (possibly bloody) abdominal cramps dehydration sepsis weight loss anaemia
how do you diagnosis acute/chronic colitis?
AxR
sigmoidoscopy + biopsy
stool cultures
barium enema
what artery is blocked for ischaemic colitis to take place?
inferior mesenteric artery
where is the most common site for angiodysplasia?
right side of colon
what are the treatment options of colonic angiodysplasia?
embolisation
endoscopic ablation
surgical resection
what are volvulus’s usually caused by?
chronic constipation
what is the mechanisms of a volvulus?
bowel twists on mesentery -may cause it to become gangrenous
how do you treat a sigmoid vovulus?
flatus tube
surgical resection
what are polyps?
protrusions above the epithelial surface
-hyperplastic growth
what are adenomas of the colon?
benign tumours- dysplastic growth
ie non invasive, don’t metastasise
what is the risk with adenomas?
precursors of colorectal adenocarcinomas
why must all adenomas be removed?
because they are premalignant
how are adenomas removed?
endoscopically or surgically
what are the dukes stagings of colorectal carcinoma?
dukes A: confined by muscularis propria
dukes B: through muscularis propria
dukes C: metastatic to lymph nodes
dukes D: distant mets
what are the 3 main symptoms with left sided colorectal carcinomas? (75%)
rectal bleeding
altered bowel habit
obstruction
what are the 2 main symptoms with right sided colorectal carcinomas? (25%)
anaemia
weight loss
where is the usual lymphatic spread from a colorectal carcinomas?
mesenteric nodes
where is the usual haematogenous spread from colorectal carcinomas?
liver
what are 2 important inherited colorectal cancer syndromes?
heriditary non polyposis coli (HNPCC)
familial adenomatous polyposis (FAP)
which inherited colorectal cancer syndrome has the on average greatest number of polyps?
familial adenomatous polyposis (FAP)
compare the onset of heriditary non polyposis coli and familial adenomatous polyposis?
HNPCC: late onset
FAP: early onset
what type of inheritance are inherited coloretal cancer syndromes?
autosomal dominant
what is the defect within heriditary non polyposis coli?
defect in DNA mismatch repair
what is the defect within familial adenomatous polyposis?
defect in tumous supression
compare the locations of heridatry non polyposis coli to familial adenomatous polyposis?
HNPCC: right sided tumours
FAP: thorugh colon
compare the inflammatory responses of heriditary non polyposis coli and familial adenomatous polyposis?
HNPCC: crohns like inflammatory response
FAP: no specific inflammatory response
compare the histological classes of cancers between heriditary non polyposis coli adn familial adenomatous polyposis?
HNPCC: mucinous tumours
FAP: adenocarcinomas
what other cancers is heriditary non polyposis coli associated with?
gastric carcinoma
endometrial carcinoma
what other cancer is familial adenomatous polyposis associated with?
desmoid tumours and thyroid carcinomas
what are the most common benign colorectal neoplasia?
adenoma
what are the most common malignant colorectal neoplasia?
adenocarcinoma
what do all adeno-carcinomas start as?
adenomas
what are proto oncogenes?
promote cell growth and division
what are oncogens?
mutated proto oncogenes that cause excessive cell growth and division
what are tumour suppressor genes?
suppress cell growht and division
what happens when tumour suppressor genes mutate?
they allow uncontrollable cell growth and divison
when a proto oncogene mutates into a oncogene what happens- loss of function of gain of function?
gain of function
when a tumour suppressor gene mutates what happens- loss of function or gain of function?
loss of function
what are the 3 macroscopic appearances of colorectal cancers?
polypoidal
ulcerative
annular
what are the 2 main classes of adenomas of the colon?
tubular
villous
which type of adenoma of the colon is more likely to form an adenocarcinoma?
villous adenomas
what is T1 of TNM staging?
cancer has invaded submucosa only
ie dukes A
what is T2 of TNM staging?
cancer has invade into muscle layer
ie dukes stage A
what is T3 of TNM staging?
cancer has invade through the muscle layer
ie dukes stage B if no mets)
what is T4 of TNM staging?
cancer has invaded into adjacent structures
ie dukes stage B if no mets
what is N0 of TNM staging?
no lymph node involved
what is N1 of TNM staging?
less than or equal to 3 nodes involved
what is N2 of TNM staging?
more than 3 lymph nodes involved
what is M0 of TNM staging?
no distant mets
what is M1 of TNM staging?
distant mets
what are the 3 protective lifestyle factors from colorectal cancer?
vegetables
fibre
exercise
what are the 4 causative lifestyle factors of colorectal cancer?
red and processed meat
smoking
alcohol
obesity
how does exercise protect from colorectal cancer?
exercise activated AMPkinase (which is also up regulated by tumour suppressore proteins) which increases glucose uptake by muscle and decreases cell turnover
what is the only treatment for familial adenomatous polyposis?
resection of the colon
what are the 3 most important predisposing conditions of colorectal cancer?
adenomatous polyps
UC
crohns
(background of chronic inflammation)
if a patient over 50 presents with iron-deficiency anaemia what should your number one thought be?
colorectal cancer
how do you diagnose a colorectal carcinoma?
barium enema
CT colography
sigmoidoscopy
colonoscopy (gold standard)
what is the screening test for colorectal carcinoma?
faecal occult blood testing
FOBT
in what type of patients is FOBT useful?
asymptomatic patients NOT symptomatic
what investigations do you use to stage colorectal carcinoma?
primary rectal cancer: -CT or MRI look for liver mets: -US or CT look for lung mets: -CXR or CT
what are the 3 main emergency presentations of colorectal cancer?
obstruction
bleeding
perforation
what does obstruction present as?
distension
constipation
pain
(vomiting)
what are the 3 treatment options of obstruction?
colostomy alone
resection and colostomy
stenting
what are the 3 treatment options of colorectal cancer?
surgery
radiotherapy
chemotherapy
why do you use radiotherapy for rectal cancer?
adjuvant (pre/post op)
palliative
what is the fucntion of radiotherapy as an adjuvant in addition to surgery for a rectal cancer?
pre-op: shrinks cancer to make it more operable
post op: reduces local recurrence after rectal excision
when palliative radiotherapy for colorectal cancer used?
for inoperable primary rectal cancer or recurrent rectal cancer
what specific chemotherapy agent is used as an adjuvant for stage C colorectal cancer?
5-FU
5-fluorouracil
what is ileus?
paralysis of intestinal motility
what is ileus caused by?
handling of the bowel peritonitis retroperitoneal injury immobilisation hypokalaemia drugs
what is the presentation of ileus?
vomiting
abdominal distension
dehydration
silent abdomen
what causes throbbing pain?
inflammation
what causes colicky pain?
obstruction
what type of blood is vomitted in ‘coffee ground’ vomit?
digested blood
how do haemorrhoids present?
painless bleeding
fresh blood, not mixed with stool
perianal itchiness
no change in bowel habit
what degree piles shows obvious haemorrhoids?
3rd degree piles
what are the management options of symptomatic haemorrhoids?
sclerosation therapy rubber band ligation open haemorrhoidectomy stapled haemorrhoidectomy haemorrhoidal artery ligation operation (HALO)
what imaging technique is used to help visualise the haemorrhoids for haemorrhoidal artery ligation operation?
doppler ultrasound
compare a partial rectal prolapse to a complete rectal prolapse?
partial- involves mucosa only
complete- involves all layers of the wall
how do rectal prolapses present?
protruding mass from anus- more prominent during defecation
bleeding and passing mucus per rectum is common
on PR exam of a rectal prolapse what do you find?
protruding mass
poor anal tone
what is an anal fissure?
a tear in the anal margin due to passage of a constipated stool
what is the treatment of a complete rectal prolapse?
rectoplexy or resection
what is the management of an incomplete rectal prolapse?
in children: dietary advice (increase fibre) and treatment of constipation
adults: haemorrhoidectomy
how do anal fissures present?
acute onset of severe anal pain usually following an episode of constipation
(pain lasts 30 mins after defecating)
bright rectal bleeding
what are the treatment options for anal fissures?
dietary advice stool softners pharmacological sphyncterotomy lateral sphyncterotomy botox injection
what are the 2 types of ischaemia of the small bowel?
mesenteric arterial occlusion
non occlusive perfusion insufficiency
what are the 2 main reasons for mesenteric arterial occlusion?
mesenteric artery atherosclerosis
thromboembolism from heart (eg A fib)
what are the 4 main reasons for non occlusive perfusion insufficiency of the blood supply to the small bowel?
shock
strangulation
drugs
hyperviscosity
which layer of the bowel wall is most sensitive to effects of hypoxia?
mucosa
in non occlusive ischaemia when does most of the tissue damage actually occur?
after reperfusion
what is the outcome of a mucosal infarct of the small bowel?
regeneration with mucosal integrity restored
what is the outcome of a mural infarct of the small bowel?
repair and regeneration leaving a fibrous stricture
what is the outcome of a transmural infarction of the small bowel?
gangrene
which is more common- primary or secondary tumours of the small bowel?
seconday tumours
what are the 3 main types of primary tumours?
lymphomas
carcinoid tumours
carcinomas
where is the most commonest site for a carcinoid tumour of the small bowel?
appendix
what is coeliacs disease?
an abnormal reaction to gluten which damages enterocytes and reduces absorptive capacity
what immune cell is the main mediator of coeliacs disease?
intra-epithelial lymphocytes
what happens to the villi in coeliacs disease?
destroyed, flat duodenal surface forms
what are the main metabolic effects of coeliacs disease?
- malabsorption of sugars, fats, amino acis, water and electrolytes
- reduced intestinal hormone production
what does reduced intestinal hormone production in coeliacs disease lead to?
gallstones
due to stasis of bile because of reduced CCK
what are the 5 effects of malabsorption within coeliacs disease?
loss of weight anaemia (macrocytic and microcytic) abdominal bloating failure to thrive vitamin deficiencies
what is intussusception?
when a segment of bowel wall becomes telescoped into the segment distal to it
what is the first line investigation for suspected perforation?
erect chest x-ray
what is the first line investigation for suspected appendicitis?
ultrasound
what is the first line investigation for diverticulitis?
CT
what is the investigation you should chose to do if there appears to be a bowel cause of abdominal distension?
abdominal x ray
what is the investigation you should choose to do if there appears to be a fluid cause of abdominal distension?
ultrasound
what is the main investigation procedure of haematemesis?
endoscopy
what is the main investigation procedure for dysphagia?
endoscopy or barium swallow
what is the radiological investigation for change in bowel habit?
barium enema or CT virtual colography
what is the investigation for change in bowel habit if there appears to be an inflammatory bowel disease underlying cause?
endoscopy
colonoscopy
what is the first line investigation for patient presentation with jaundice?
ultrasound
