3- IBD clinical Flashcards
what is IBD?
inflammatory bowel disease includes multiple diseases, main ones being crohn’s & ulcerative colitis →patients might not neatly fit into either of these, patients noted might have IBD/U = IBD unclassified
are symptoms good for diagnosis of IBD?
no, you usually need more than symptoms
what is problem with how immune system works in IBD?
Instead of properly distinguishing between harmful pathogens and harmless substances, the immune system in IBD reacts excessively or inappropriately to components of the gut lining, leading to chronic inflammation and tissue damage
what is immune tolerance?
the ability of the immune system to detect between gut commensals and gut pathogens
what is difference in diarrhoea for crohn’s and ulcerative colitis?
ulcerative colitis more diarrhoea with blood and crohn’s more watery diarrhoea
what is best established risk factor for IBD?
positive family history - a number of different genes have been highlighted to show linkage to IBD but unlike cystic fibrosis not one specific gene to scan for to see if have yet
what is an example of a gene related to IBD?
in chromosome 16 - mutated form of NOD2 is found in 1-20% caucasian patients with crohn’s →NOD2 encodes a protein involved in bacterial regulation
what is different with bacterial flora in colon with ulcerative colitis?
altered bacterial flora
what are 4 different thoughts of what causes IBD?
- pathogenic bacteria
- abnormal microbial composition
- if patients have defective post containment (NOD2 alteration etc) can impact how immune system deals with natural commensals
- post immune system doesn’t maintain it’s homeostasis
what areas if GI tract has lots of gut commensals?
stomach is acid = not as many commensal bacteria as other areas
bile is alkaline = more hospitable environment for commensal bacteria
moving jejunum→ileum, pH becomes less acidic and allows numbers increase and become more diverse and then in colon have much more population diversity
what happens to bacteria in crohn’s and ulcerative colitis?
in crohn’s disease →lose ability to control bacteria
ulcerative colitis →overcontrol bacteria, (maybe kill commensals)
what environmental factors can trigger flare ups?
- smoking →aggravates crohn’s but protects against ulcerative colitis
- NSAIDs →can cause inflammation within lining of gut and if used without gastric protection can cause ulcers
what is process in crohn’s from trigger to uncontrolled immune response?
people with genetic predisposition + environmental factors + secondary insult (medication, infection) →lose integrity to bowel wall →lose tolerance to own microbiome →dysbiosis (this is when thought to get problem) →increase in amount of inflammation (innate & acquired) →uncontrolled immune response (this is when patients get diagnosis as more symptoms and things can be seen)
what are different types of ulcerative colitis?
- proctitis = rectum
- left sided colitis = from rectum up to splenic flexure
- pancolitis = from rectum all the way round colon
what are symptoms of ulcerative colitis?
- diarrhoea & bleeding with diarrhoea
- increased bowel frequency (how often? - at night?)
- increased urgency
- incontinence if severe flare
- tenesmus = urge to go to toilet but no stool (sometimes can be mucous or blood)
- lower abdominal pain (lower iliac fossA)
- proctitis can cause constipation as stuff gets backed up due to inflamed
what are some important things to ask about in history?
- recent travel - could be infection
- antibiotics - could be C.diff
- NSAIDs
- family history
- smoking
- skin, eyes, joints
what defines severe ulcerative colitis?
6 bloody stools/24 hour + 1 or more of
- Fever (>37.8°C)
- Tachycardia (>90/min)
- Anaemia (Haemoglobin <10.5g/dl)
- Elevated ESR (>30mm/hr) / CRP
what risk of colectomy does severe ulcerative colitis have?
30% risk of colectomy
what is important to be measured in bloods for ulcerative colitis?
- CRP
- albumin = low albumin = bowel wall leaky as that loses albumin
- platelets = increase platelets is indirect marker of inflammation in body
what tests can be done to investigate ulcerative colitis?
- bloods
- plain abdominal x-ray
- endoscopy
- histology
what should you look for on abdominal x-ray for ulcerative colitis?
- if UC →lets us estimate extent of colon that might be involved, would expect stool in bowel that’s unaffected
- look for thumbprinting = pathognomonic of inflammation, you can see more defined bowel wall (almost looks like thumb in plasticine or playdough)
- any evidence of colon being inflamed (toxic megacolon) →assess by measuring transverse colon (greater than 5.5cm or caecum greater than 9 cm than are more at risk for sepsis etc)
what can be seen on endoscopy for ulcerative colitis?
- can see red with white pus
- see some development of ulcers
can see transition zone →where it changes to normal
normally, tip of scope can go on mucosal wall and cause no damage but in UC, touching tip on mucosal wall can cause bleeding (friable wall)
can see pseudopolyps (skin tags on lining of wall) →normal on bowel wall and can just remove them but if UC can develop pseudopolyps and won’t remove them but put on treatment and the polyps melt away
what is seen on histology biopsy for ulcerative colitis?
goblet cells missing →only affects mucosal layer (never beyond muscularis mucosa) - widening crypts
what is the main long term complication of ulcerative colitis?
increased risk of colorectal cancer
what determines extensive colitis?
- severity of inflammation
- duration of disease
- disease extent
what are extra-intestinal manifestations of ulcerative colitis?
- skin = erythema nodosum = sore bumps, often on shins but can get on upper limbs (can also happen in immune mediated arthritis)
- joint pain (often small joints )
- eyes = episcleritis, uveitis →painful whites of eyes
- deranged LFT’s - inflammation of biliary tract
- mouth - stomatitis
- oxalate renal stones (less common)
what is primary sclerosing cholangitis?
= fibrostic structures in biliary tree making deranged LFT’s →see plastic beads on string appearance →mostly asymptomatic but still have block in biliary drainage
how is PSC related to chronic inflammatory disease?
most people with PSC (primary sclerosing cholangitis) also have chronic inflammatory disease (but not all people with IBD have PSC)
what happens if untreated PSC?
liver transplant within 10 years and 15% get cholangiocarcinoma
what is distribution of crohn’s disease?
- anywhere from mouth to anus
- children more in upper GI tract and adult more small bowel or colonic
- skip lesions in crohn’s →immune response & inflammation bounces along
what type of inflammation occurs in crohn’s disease?
transmural (full thickness) inflammation
what is perianal disease?
- recurrent abscess formation
- pain
- can lead to fistula with persistent leakage
→can lead to damage sphincters causing permanent leakage
what can be done as surgery for perianal disease?
can put stitches to make seton to help heal fistula from inside out rather than outside in = helps reduce recurrence
what fistulas can occur in crohn’s disease?
fistulas = abnormal connections/passageways that form between 2 organs or organ and skin surface →can occur perianal area or small bowel loops with colon or in females with bowel & vagina, or in bowel loops through anterior abdominal wall
what inflammation can lead to stenosis?
inflammation, thickening at any party of bowel wall →decreases diameter/stenosis
what are symptoms of small intestinal crohn’s?
- Abdominal cramps (peri-umbilical)
- Diarrhoea, weight loss
what are symptoms of colonic crohn’s?
- Abdominal cramps (lower abdomen)
- Diarrhoea with blood
- Weight loss
what are symptoms of mouth crohn’s?
Painful ulcers, swollen lips, angular cheilitis
what are symptoms of crohn’s of anus?
peri-anal pain, abscess
what investigations can be done to diagnose crohn’s?
clinical exam →weight loss
bloods - CRP, albumin, platetlets, if small bowel affecting terminal ileum (where b12 absorbed) so check for b12 and ferritin (for marker of iron deficiency)
stage disease extent with colonoscopy
what is histology of crohn’s like?
- patchy inflammation
- granuloma
what are small bowel tests that can be done for crohn’s?
- MRI of small bowel
- white cell scan if people don’t like combined space
