Pathology of IBD Flashcards
what is crohns disease?
chronic inflammatory and ulcerating condition of the GI tract thatcan affect anywhere from the mouth to anus
(most common in terminal ileum and colon)
who usually presents with crohns disease?
90% are 10-40 years old
50% 20-30 years old
can occur in children
more common in males
what are the most common sites of crohns disease?
2/3rds have small bowel involvement only
1/6 have colonic/anal disease only
1/6 have both
how does crohns disease present?
abdominal pain small bowel obstruction diarrhoea bleeding PR anaemia weight loss
what is the clinical course of crohns disease?
chronic
exacerbations and remissions
unpredictable response to therapy
small number go into lasting remission within 3 years of diagnosis
describe the typical crohns patient?
22 year old male
abdominal pain
bloody diarrhoea for 3 months
tender abdomen
how is crohns investigated?
endoscopy and mucosal biopsy
describe the pattern of lesions in crohns disease?
patchy, segmental disease with skip areas anywhere in GI tract
what does crohns look like histologically?
chronic active colitis - inflammatory cells in lamina propria
non-caseating granulomas (in 50%)
crypt branching
what are the consequences if a crohns patient doesn’t respond to medical therapy (steroids etc)?
bowel obstruction
will need surgery
what might be seen in the GI tract with crohns disease?
stricture thickened wall fat wrapping ulceration (can cause fissures) skip lesions deep knife like fissures - produces cobblestoning of mucosa pseudopolyps (rare) transmural inflammation
name 2 forms of chronic mucosal inflammation associated with crohns
cryptitis
crypt abscesses
what are the possible complications of crohns disease?
malabsorption fistulas anal disease intractable disease bowel obstruction perforation malignancy amyloidosis rarely toxic megacolon
what might cause malabsorption in crohns disease?
short bowel syndrome due to repeated resections and recurrences
hypoproteinaemia, vitamin deficiency, anaemia
gallstones
what fistulas might form in crohns disease?
VesicoColic EnteroColic GastroColic RectoVaginal TuboOvarian abscess Blind loop syndrome
what anal diseases might occur in crohns disease?
sinuses fissures skin tags abscesses perineum falls apart
what is intractable disease?
failure to tolerate or respond to medical therapy
continuous diarrhoea or pain
may require surgery - total colectomy
where is crohns disease incidence high/low?
high in north America, Europe and Scotland
low in Africa, Asia and south America
does ethnicity affect the incidence of crohns disease?
more common in jewish people than arab people in isreal
less common in Ashkenazi jews living in isreal vs the USA
is there a genetic link in crohns disease?
possibly
44% concordance in monozygous twins
possibly NOD2 gene on chromosome 16
association with HLA-DR1 and HLA-DQw5
what environmental triggers can worsen IBD?
smoking infectious agents vasculitis sterile environment theory NSAIDs
describe the aberrant immune response in crohns disease
persistent activation of T cells and macrophages (failure to switch off)
excess pro-inflammatory cytokine production
maybe alterable by changing intestinal microflora
what is the likely pathogenesis of crohns disease?
genetic susceptibility to environmental agent(s) which prevents a controlled and effective response to a trigger
what 4 things can cause crohns?
luminal microbial antigens and adjuvants
genetic susceptibility
environmental triggers
immune response
