Inflammatory Bowel Disease Flashcards

1
Q

What are the two main diseases that come under Inflammatory Bowel Disease?

A

Ulcerative Colitis

Crohn’s Disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the underlying pathogenesis of these diseases based on?

A

It boils down to a defective interaction between the mucosal immune system and gut flora causing chronic inflammation of the gut wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of IBD is obesity a risk factor for?

A

Crohn’s Disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which T cell responses are involved in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
Th2

b. Crohn’s Disease
Th1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the main cytokines in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
IL-13

b. Crohn’s Disease
TNF-alpha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which layers of the gut are affected in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
Mucosa + Submucosa

b. Crohn’s Disease
All Layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe which regions of the gut are affected in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
Starts at the rectum and proceeds proximally (continuous inflammation)

b. Crohn’s Disease
Can be anywhere on the GI tract (mouth to anus)
Patchy inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Are abscesses, fissures and fistulae common in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
No

b. Crohn’s Disease
Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the effectiveness of surgery in:

a. Ulcerative
b. Crohn’s Disease

A

a. Ulcerative Colitis
Curative

b. Crohn’s Disease
Not always curative, even if the affected area is cut out, it often reoccurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe some supportive therapies that are given for IBD

A

Nutritional therapy

Fluid/electrolytes

Potentially even blood transfusions/oral iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the three types of classic symptomatic treatment for IBD?

A

Aminosalicylates
Glucocorticoids
Immunosuppressants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the main aminosalicylate drug?

A

Mesalazine

AKA 5-aminosalicylic acid (5-ASA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a slightly more complex aminosalicylate?

A

Olsalazine (this is 2 x 5-ASA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of drug are aminosalicylates?

A

Anti-inflammatory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the mechanism of anti-inflammatory action of aminosalicylates.

A

1) They inhibit NF-Kabba B/MAPK:
Reduces levels of TNF-α, IL-1β and IL-6

2) Also inhibits COX-2:
Decreased production of PGE2 and PDF2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the activation of aminosalicylates.

A

Mesalazine does not have to be activated any further

Olsalazine must be activated by colonic flora

17
Q

Describe the effectiveness of aminosalicylates in Ulcerative Colitis and Crohn’s Disease.

A

They are effective at inducing and maintaining remission in UC

They are better than steroids at inducing remission in UC

They are less effective in CD

18
Q

Describe the use of glucocorticoids in IBD.

A

Use of glucocorticoids in UC is in decline because aminosalicylates are better

Glucocorticoids are still the drug of choice for inducing remission in CD

However, many side effects are likely if they are used to maintain remission

19
Q

Describe some strategies for minimising the side effects of glucocorticoids.

A

Topical administration (e.g. enemas and suppositories)

Low dose

Use oral or topically administered glucocorticoid with a high first pass metabolism

20
Q

What is an example of a glucocorticoid that has relatively few side effects?

A

Budesonide

21
Q

Describe the effectiveness of budesonide compared to other glucocorticoids.

A

Budesonide has fewer side effects than other glucocorticoids but it is less effective at inducing remission in CD

22
Q

State three immunosuppressive agents that could be used in IBD.

A

Azathioprine
Methotrexate
Cyclosporin – only useful in severe UC

23
Q

Describe the onset of action of azathioprine.

A

Slow onset – can take 3-4 months

24
Q

Describe the activation of azathioprine.

A

Azathioprine needs to be metabolised by gut flora to 6-mercaptopurine

25
Q

Describe the mechanism of action of azathioprine.

A

6-mercaptopurine is a purine antagonist

It interfered with DNA synthesis and cell replication

It impairs:
 Cell- and antibody-mediated immune responses

 Lymphocyte proliferation

 Mononuclear cell infiltration

 Synthesis of antibodies

It enhances:
 T cell apoptosis

26
Q

What are the unwanted effects of azathioprine?

A

Nearly 10% of patients stop treatment because of the side effects

Pancreatitis

Bone marrow suppression

Hepatotoxicity

Increased risk (4 fold) of lymphoma and skin cancer

27
Q

Describe the metabolism of azathioprine.

A

There are four routes of metabolism of azathioprine

Route resulting in inhibition of de-novo purine synthesis (HGPRT pathway produces 6-TIMP –> 6-MeMPN)

 Route resulting in the production of beneficial active metabolites that also cause myelosuppression (HGPRT pathway produces 6-TIMP –> 6-TGN)

 Route resulting in hepatotoxic metabolites with no beneficial effect (TPMT produces 6-MMP)

Xanthine Oxidase Pathway– produces inert metabolites (6-TU)
Xanthine oxidase is, fortunately, the main route of azathioprine metabolism

28
Q

In what clinical situation could there be a problem with azathioprine metabolism?

A

If the patient is taking allopurinol

Allopurinol is used to treat gout and is a xanthine oxidase inhibitor

This will result in the azathioprine being shunted down the hepatotoxic and myelosuppressive routes of metabolism

29
Q

What are the three potential mechanisms of manipulating the gutmicrobiome?

A

Nutrition based therapies – probiotics could be useful in remission of UC

Faecal Microbiota Replacement Therapy (FMT) – could be useful in UC

Antibiotics – Rifaximin
 Interferes with bacterial transcription by binding to RNA polymerase

 Induces and sustains remission in moderate CD

 Potentially beneficial in UC

30
Q

Give an example of anti-TNF-alpha antibody.

A

Infliximab (IV)

31
Q

Describe the effectiveness of anti-TNF- antibodies in Crohn’s Disease.

A

60% of patients will respond within 6 weeks are it is potentially curative

32
Q

Describe the mechanism of action of anti-TNF-alpha antibodies.

A

Knocking out TNF-alpha leads to general down regulation of other inflammatory cytokines

Reduced infiltration and activation of leukocytes

Induced cytolysis of cells expressing TNF-alpha

Promotes apoptosis of activated T cells

33
Q

Describe the pharmacokinetics of anti-TNF-alpha antibodies.

A

Given intravenously

Long half-life – 9.5 days

Most patients relapse between 8-12 weeks

Repeat infusion given after 8 weeks

34
Q

What is a problem with anti-TNA-alpha therapy that may require changes in the treatment guidelines?

A

Evidence showed up to 50% of responders stopped responding after 3 years

This is due to production of anti-drug antibodies and increased drug clearance

35
Q

What are the adverse effects of anti-TNA-alpha therapy?

A

Increased risk of tuberculosis

Risk of reactivating dormant TB

Increased risk of septicaemia

Worsening heart failure

Increased risk of demyelinating disease

Increased risk of malignancy

Can be immunogenic

36
Q

What are the 4 biggest risk factors for IBD?

A

Genetics
Microbiome
Diet
Smoking

37
Q

What are some methods for targetted drug delivery?

A
  1. Coated in a pH dependent polymer
  2. Coated in a time dependent polymer
  3. Taken as a prodrug broken down by colonic bacteria
  4. Coated in an osmotically controlled coating system.
    * new class emerging combining time and pH methods.
38
Q

What is infliximab very good at?

A

Maintaining fistula closure.

39
Q

Why does Budesonide cause fewer side effects than prednisolone?

A

It is metabolised and inactivated loacally