MBChB Year 2: Inflammatory Bowel Disease

Questions and Answers

What type of immune response characterizes inflammatory bowel disease?

Autoimmune responses to gastrointestinal cells

Overactive immune responses to gut flora (correct)

Inadequate immune responses to gut flora

Allergic responses to dietary substances

Which of the following statements about Crohn disease is true?

It can involve any area of the gastrointestinal tract. (correct)

It only involves the mucosal layer of the intestines.

It exclusively affects the colon.

It primarily affects the rectum.

At what age does inflammatory bowel disease typically present?

During adolescence and early twenties (correct)

In late adulthood

During childhood only

In middle adulthood

Which population is more likely to be affected by inflammatory bowel disease?

Individuals in developed countries Signup and view all the answers

What is a possible factor contributing to the pathogenesis of inflammatory bowel disease?

Defects in host interactions with gastrointestinal flora Signup and view all the answers

What is a common clinical feature presented by patients with Crohn's disease?

Intermittent attacks of abdominal pain Signup and view all the answers

What can extensive Crohn's disease lead to?

Iron deficiency anemia and malnutrition Signup and view all the answers

Which extraintestinal manifestation is associated with Crohn's disease?

Erythema nodosum Signup and view all the answers

In which location does ulcerative colitis primarily occur?

Rectum and colon Signup and view all the answers

What is a key morphological feature of ulcerative colitis?

Inflammatory pseudopolyps Signup and view all the answers

The tips of the pseudopolyps fuse to form what structure?

Adhesions Signup and view all the answers

What is a potential complication for patients with long-standing colon involvement in Crohn's disease?

Increased risk of colonic malignancy Signup and view all the answers

What condition often requires surgical resection in patients with extensive Crohn's disease?

Fibrotic strictures or fistulas Signup and view all the answers

Which type of ulcers are associated with mucosal inflammation in this condition?

Nodular ulcers Signup and view all the answers

Which complication is associated with damage to the muscularis propria?

Toxic megacolon Signup and view all the answers

What indicates the absence of granulomas in diagnosing Crohn's disease?

Absence of granulomas does not rule out Crohn's disease Signup and view all the answers

What microscopic feature is NOT seen in this condition?

Fissures Signup and view all the answers

What is a common presenting symptom in patients with this condition?

Bloody mucoid diarrhoea Signup and view all the answers

Extra-intestinal manifestations include all of the following EXCEPT:

Dermatitis herpetiformis Signup and view all the answers

What factor increases the risk of colonic adenocarcinoma in this context?

Duration of active inflammation Signup and view all the answers

Which statement regarding the risk of malignancy in IBD is true?

Increases with severity of disease Signup and view all the answers

What is the consequence of TNF release in a susceptible host regarding mucosal permeability?

It increases the permeability of epithelial cells. Signup and view all the answers

Which genetic factor has been linked to Crohn's disease?

NOD2 polymorphisms. Signup and view all the answers

In Crohn's disease, helper T cells are primarily polarized to produce which type of cytokines?

TH1 cytokines. Signup and view all the answers

What common gastrointestinal locations are primarily affected by Crohn's disease?

Ileocecal valve and cecum. Signup and view all the answers

What is a characteristic gross feature of Crohn's disease?

Skip lesions and transmural inflammation. Signup and view all the answers

Which of the following represents a common microscopic feature seen in Crohn's disease?

Intraepithelial neutrophils and crypt abscesses. Signup and view all the answers

What role does microbiota play in managing inflammatory bowel disease (IBD)?

Microbiota can be helpful in managing IBD. Signup and view all the answers

Which cytokine receptor polymorphisms may play a protective role in Crohn's disease?

IL-23 receptor. Signup and view all the answers

What feature of Crohn's disease may result in a cobblestone appearance in the intestines?

Sparing of interspersed mucosa. Signup and view all the answers

Which feature is NOT associated with ulcerative colitis (UC)?

NOD2 polymorphisms. Signup and view all the answers

Study Notes

Inflammatory Bowel Disease (IBD)

IBD is a chronic condition characterized by inappropriate immune responses to normal gut flora.
It includes two main disorders:
- Ulcerative colitis (UC), which is confined to the colon and rectum, affecting mucosa and submucosa.
- Crohn disease (CD), known for regional enteritis that can impact any part of the gastrointestinal tract, exhibiting transmural involvement.

Epidemiology

Predominantly observed in developed countries, consistent with the hygiene hypothesis.
Presents in adolescence and early twenties.

Pathogenesis

IBD is idiopathic, resulting from:
- Host interaction defects with gastrointestinal flora.
- Intestinal epithelial barrier dysfunction.
- Aberrant mucosal immune responses leading to increased permeability.
Transepithelial microbial flux triggers immune responses, creating a self-amplifying cycle resulting in IBD.
Genetic factors include higher disease risk in affected families and a 50% concordance in monozygotic twins for CD.

Genetics and Immune Responses

NOD2 polymorphisms linked to CD; regulates immune response to luminal microbes.
Other genes like ATG16L1 and IRGM are involved in microbial recognition.
CD is associated with polarized TH1 responses, while UC shows TH2 responses.
IL-23 receptor polymorphisms may provide protection in CD, whereas IL-10 gene polymorphisms are linked to UC.

Epithelial Defects and Microbiota

Barrier dysfunction due to tight junction defects and transporter gene alterations.
Microbiota composition influences immune responses; altering gut flora can aid in managing IBD.

Crohn Disease Morphology

Can appear in any gastrointestinal tract area; most common in the ileum, ileocecal valve, and cecum.
Typically presents with skip lesions and granular serosa, thickened rubbery bowel wall, and stricture formation.

Gross Features of CD

Aphthous ulcers and cobblestone appearance due to interspersed mucosa elevation.
Fistula tracts and granulomas may develop, with granulomas possible in mesenteric lymph nodes.

Clinical Features of CD

Intermittent attacks include diarrhea, fever, and abdominal pain, with asymptomatic periods lasting weeks or months.
Extensive CD can lead to malnutrition, iron deficiency, B12 deficiency, and protein-losing enteropathy.
Surgical resection often needed for complications like fibrotic strictures or fistulas, with recurrence seen in 40% at anastomoses.
Extraintestinal manifestations may include uveitis, sacroiliitis, and an increased risk of colonic cancer.

Ulcerative Colitis Morphology

UC affects the colon in a continuous manner from the rectum upward; skip lesions are absent.
Involves mucosal inflammation with potential backwash ileitis.

Gross Features of UC

Characterized by reddened, granular mucosa with inflammatory pseudopolyps and extensive ulcers.
Mucosal damage can lead to toxic megacolon and perforation.

Microscopic Features of UC

Mucosal inflammation primarily affects the mucosa and submucosa; features include crypt abscesses and glandular distortion.
Granulomas, skipped lesions, and fissures not present.

Clinical Features of UC

Patients experience intermittent bloody mucoid diarrhea and abdominal pain with relapses common.
Extraintestinal manifestations include joint pain, uveitis, and skin lesions; increased risk of colon cancer persists.

Indeterminate Colitis

10% of IBD patients cannot be definitively classified between UC and CD.

Colitis Associated Neoplasia

Risk of malignancy rises 8 to 10 years after onset of IBD, greater in extensive disease.
Patients require regular surveillance with biopsies for early detection of neoplasia.

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Description

This quiz covers Inflammatory Bowel Disease (IBD), focusing on its chronic nature and the immune responses involved. It includes details on the two primary disorders associated with IBD, making it essential for students of the GIT and hepatobiliary system. Test your understanding of this important medical topic.