IBD Flashcards
List commonalities between CD and UC
- Bowel inflammation
- No proven etiologic agent
- Patterns of familial occurrence
- Systemic manifestations
Contrast UC and CD
CD
- entire GI tract
- skip lesions
- strictures common
- transmural inflammation
- perianal disease
- fat/ vitamin malabsorption
UC
- colon only
- rectum always involved
- continuous inflammation
- strictures are rare and assumed to be cancer
- mucosal and submucosal inflammation only
- no perianal disease
- no fat or vitamin malabsorption
Describe epidemiology of IBD
Caucasians>African Americans>Hispanics and Asians
Geography: norther latitudes
male predominance in UC, female predominance in CD especially during adolescence
List three components of the pathology of IBD
Genetic susceptibility
Immune dysregulation
Environmental triggers
What is believed to be the mechanism of immune dysregulation in IBD?
Loss of immune tolerance to normal bowel flora leading to over responsiveness of mucosal T cells
Traditionally thought that this was largely a problem of acquired immune system but no there is evidence for involvement of innate immune system
Differentiate the immunologic phenotypes of CD vs UC
CD is often described as a Th1 disease because the primary mediators of inflammation are Th1 cytokines (IL-12, IFN-γ, TNF-α).
UC is often described as a Th2 disease because of studies showing increased mucosal expression of IL-5, a Th2 cytokine.
List some candidate genes associated with IBD
NOD2 aka CARD15
IL-23 receptor
ATG16L1 and IRGM
List environmental factors associated with IBD
- Smoking: appears to be protective for UC but a risk for CD
- appendectomy
- NSAIDs
- OCPs
- breastfeeding is protective
- diet (no specific links found)
- infectious agents (no definitive links)
- hygiene hypothesis
- stress
Skip lesions can be seen in _______
Crohn’s disease
Inflammation in Crohn’s disease is _____
transmural, full thickness
List complications of Crohn’s disease
- stricture formation
- fistula formation
- perforation
- perianal Crohn’s: abscess
- gallstones
- adenocarcinoma of colon, risk of colon cancer if more than 1/3 of colon is involved
How is Crohn’s disease diagnosed?
history and physical
Colonoscopy with terminal ileoscopy including biopsies
Colonoscopy in a person with Crohn’s disease may show _____ ulcers
aphthous
small ulcers limited to the mucosa
What will be seen on tissue biopsy that suggests a diagnosis of Crohn’s disease?
evidence of chronic inflammation.
Discrete, non-caseating granulomas
Longitudinal or stellate ulceration and mucosal cobblestoning
What laboratory markers can aid in making a diagnosis of Crohn’s disease?
elevated CRP and ESR
possible anemia
What imaging studies are used to make a diagnosis of Crohn’s disease?
CT, MRI, ultrasound, and fluoroscopic imaging (e.g., small bowel follow through or small bowel enteroclysis).
______ is the hallmark symptom of ulcerative colitis
Hematochezia- bloody diarrhea
others: abdominal apin, anemia, incontinence
In ulcerative colitis, inflammation is limited to the
mucosa and submucosa
How is ulcerative colitis diagnosed?
colonoscopy and biopsy- erythematous and friable mucosa with superficial ulceration, rectum is always involved
pseudopolyps
tissue biopsies show characteristic crypt abscess
The hallmark lesion of UC on biopsy is:
crypt abscess, collections of PMNs at base of crypts
What lab studies aid in the diagnosis of ulcerative colitis?
CBC, CRP, ESR, iron studies, and liver tests
List complications of ulcerative colitis
toxic megacolon
PSC
colon cancer- need routine screening
NOT fistulae, because not a full thickness disease
Describe extra-intestinal manifestations of IBD that are related to disease severity
L arge joint peripheral arthritis
Erythema nodosum
Episcleritis
Aphthous ulcers of mouth (CD)
Describe extra-intestinal manifestations of IBD that are usually related to disease severity
Pyoderma gangrenosum (deep skin ulcers) Anterior uveitis
Describe extra-intestinal manifestations of IBD that are not related to disease activity
Sacroiliitis
Small joint symmetric arthritis
Ankylosing spondylitis
PSC, cholangiocarcinoma (UC)
Others, rare: pericarditis, amyloidosis, autoimmune hepatitis
What is microscopic colitis?
lymphocytic colitis and collagenous
colitis.
characterized by chronic watery diarrhea and normal findings on colonoscopy and radiology, but microscopic inflammation on colon biopsies.
What is treatment for microscopic colitis?
discontinue NSAIDs, caffeine, and dairy
antidiarrheals
What are the clinical features of microscopic colitis?
chronic or intermittent watery diarrhea which can be severe
commonly occurs with other autoimmune conditions
link to celiac disease
