Inflammatory Bowel Disease Flashcards
what Dx do the following symptoms indicate?
s/s: loose stools (10/d), blood in stool, LLQ abd cramping that improves with defecation, diarrhea at night!
Ulcerative colitis
PE: fever, orthostatic hypotension, tachy, LLQ tenderness (no rebound or peritoneal signs)
Rectal exam: BRB (bright red blood per rectum)
exam indicates what DDx?
infectious diarrhea, IBS, IBD –> Ulcerative colitis
orthostatic hypotension indicative of…?
dehydration
Red flags that indicate ulcerative colitis?
blood in stool, nocturnal diarrhea, young age
Lab results indicate what Dx?
elevated WBC (mostly neutrophils), low Hgb, elevated ESR
stool: leukocytosis, -ve bacterial cultures
CT abdomen: thickening of sigmoid and descending colon (no abscess or diverticula)
ulcerative colitis
what are the proper steps in Dx of UC?
HPI, PE, stool sample, CBC, CT abdomen, colonoscopy
what is colitis?
damage to the mucosa of the colon
diffuse mucosal granularity, erythema, exudate
colonoscopy of UC description = colitis
distortion of crypt architecture (long term problem) crypt abscesses (full of inflammatory cells)
UC biopsy
diagnosis?
- young female on HRT (oral contraceptives)
- watershed areas of colon affected
- sparing of rectum
ischemic colitis (the whole colon is not affected)
watershed areas of colon
splenic flexure and rectosigmoid junction (limited blood supply here)
blood supply to the large intestine
SMA from aorta supplies terminal ileum IMA supplies left side of colon
diagnosis?
mimics UC but biopsy shows virus for differentiation
CMV colitis
three classifications of UC
proctitis, left sided colitis, pancolitis
what is the diagnosis?
s/s: bloody diarrhea, abd pain, fecal urgency, disease limited to colon (does NOT spread to SI)
rectum is involved & inflammation is limited to mucosa and submucosa
Ulcerative colitis
complex immunological disorder w/ complex pathogenesis
chronic idiopathic intestinal inflammation
IBD
idiopathic disease: combo of genetics, bacteria, and immunological response
IBD
two main subtypes of IBD
UC and Crohn’s disease
UC vs Crohn’s disease
Crohn’s is any part of the GI tract (including SI)
UC starts at anus and is uninterrupted
IBD epidemiology
bimodal peak: 15-25 y/o and 50-70 y/o
more common in Ashkenazi Jews
what is a risk factor for Crohn’s disease but NOT a risk factor for UC?
appendectomy
smoking and IBD
UC: better prognosis if you smoke
Crohn’s: worse prognosis if you smoke
IBD seen in what climates/countries?
colder climates and developed countries
hygiene hypothesis
increased frequency to Abx, less exposure to bacteria…extreme sanitation leading to higher incidence of IBD
water absorption in GI tract
> 200 cc of stool = diarrhea
normal intestinal electrolyte absorption
Na: electrogenic Na abs and electroneutral NaCl abs
K: secretion & absorption
Cl: secretion
short chain FA abs
H2O: doesn’t need transporters
IBD causes ________ diarrhea
inflammatory
secretory diarrhea
excess electrolytes (NaCl) w/ water following
AKA massive volume of plasma-like fluid
inflammatory diarrhea
inflammatory mediators affect apical membrane transporters:
- so Na abs is diminished (leading to more water in the lumen as well now)
- so Cl secretion is therefore increased as well
what does IBD do exactly to cause defective Na absorption?
1) colonocyte properites change when inflammed
2) there is reduced Na pump activity
3) high [inflammatory cytokines] result in gene depression of enterocyte cellular transport function
name one inflammatory cytokine involved in IBD leading to disturbed colonocyte function
TNF
List of other possible causes of diarrea in IBD
bile induced, fatty diarrhea, short bowel syndrome, concurrent C diff colitis, CMV, SI bacterial overgrowth, celiac sprue, untreated lactose intolerance, NSAID associated enteropathy, IBS
inflammatory diarrhea can be caused by either _______ or ________
infectious diarrhea or immunological diarrhea
infectious diarrhea (left) and immunological diarrhea (right)
IBD is immunological. this is when activation of immune system causes severe inflammation, damage of enterocyte, and malabs.
pathogenesis of IBD (two factors that play a role)
- host (genetics + immune system)
- microbes in the lumen
pathogenesis of IBD (specific immunological reasons)
excessive immune reactivity OR inadequate immune responses to intestinal microbiota
microbiome bs microbiota
microbiome: ecological community of pathogenic microorganisms (bacteria, fungus, yeast) and humans themselves
microbiota: ONLY microorganisms
* There are 10x more bacterial cells than human cells*
gut flora has the largest # of bacteria/greatest # of species compared to any other area of the body
when is this gut flora established in the human body?
1-2 years after birth
what dominates the micronbiota?
bacteriodetes and Firmicutes
+ve role of microbes
nutrition, energy metabolism, proper “conditioning of intestinal & peripheral immune systems
-ve role of microbes
microbial-derived factors promote IBD in the context of underlying genetic immune defect
what leads to changes in the communities of intestinal bacteria?
dietary factors, helminth exposure, Abx exposure
What four ways does the mucosal layer above enterocytes protect us?
- intact intestinal epithelium
- secretion of protective factors
- innate immune system
- acquired immune system