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