IBD/Diverticulosis

Question 1

What are subtypes of IBS?

Answer 1

1. With constipation
2. With diarrhea
3. Mixed

Question 2

What is role of motility in IBS?

For subtype C vs. D

Answer 2

C: 25% have slow colonic transit
D: 15-45% accelerated colonic transit; increased frequency and irregularity of luminal contractions or exaggerated motor response to CCK/meal ingestion

Question 3

What types of visceral hypersensitivity could be seen in IBS?

Answer 3

Increased sensation in response to stimuli
Abnormal stimulus
Abnormal central pain processing

Question 4

What is evidence of altered perception in IBS? (2)

Answer 4

Increased levels of awareness/pain at lower distention levels
Gas retention increased

Question 5

What findings related to micro biome have been seen in IBS? (3)

Answer 5

Altered microbiome
Rifaximin (an abx) improves IBS without constipation
Risk of IBS increases after infection

Question 6

What is SIBO? What is its role in IBS?

Answer 6

SIBO: overgrowth of bacteria in SI

Treating SIBO reduces symptoms in IBS (methane/hydrogen cause abdominal pain, bloating)

Question 7

What types of carbs have been associated with inducing symptoms in IBS?

What happens when you lower these carbs?

Answer 7

FODMAPs=fermentable oligosaccharides, disaccharides, monosaccharides and polyols

Altered diet can produce response in IBS

Question 8

What is lipid effect on GI tract motility/sensitivity in functional gastrointestinal disorder pts?

Answer 8

Reduced small bowel gas transit
Increased gastrocolonic reflex (colonic motility)
Increased gut distention and sensitivity

Question 9

Is there a role of food allergies in IBS?

Answer 9

I mean maybe a little but not really

Question 10

What is role of gluten in IBS?

Answer 10

Gluten=increased symptoms and increased small bowel permeability in IBS-D pts (especially those with HLA-DQ2/8)

Gluten free diet would be a good idea here

Question 11

What immune cells (2) and mediators (4) are increased in intestines in IBS?

Answer 11

Immune cells: mast cells, lymphocytes

Mediators: NO, Histamine, Proteases, TNF

Question 12

What is result of increased inflammation in IBS on mucosal permeability?

Answer 12

Increased mucosal permeability=>See cycle thing on slide 48

Question 13

What is relationship between psychosocial factors and IBS? (3)

Answer 13

Early adverse life events associated with increased IBS
Patients with IBS are more likely to have experienced abuse
IBS pts have increased anxiety, depression, phobias and somatization

Question 14

How does stress interact with IBS?

Answer 14

Continued stress affects clinical outcome

Question 15

What is difference between true and false diverticulum?

Answer 15

True contains all layers of wall

Question 16

What is presentation of diverticulosis?

Answer 16

usually asymptomatic

25% develop diverticular disease (15% of those develop complications)

Question 17

What is prevalence of diverculosis?

Answer 17

Increases with age==>
40%>60
65% at age 80

Question 18

How does diverticulosis vary by geography?

Answer 18

In westernized nations, it is mainly left sided and acquired

In asia, it is mainly right sided and genetic/congenital

Question 19

In which locations is diverticulosis most common?

Answer 19

95-99% have descending colon diverticulosis (35% also have more proximal disease)
Develop at points where vasa recta penetrate circular muscle layer

Question 20

What are roles of the two smooth muscle layers in the colon?

Answer 20

Longitudinal: teniae coli; pulls colon to shorter functional length

Circular muscle: thickens in regular bands of contraction; controls peristalsis

Question 21

What alteration in muscle layer is seen in diverticulosis?

Answer 21

Increased elastin composition leads to thickened taenia coli

Highly contractile normal muscle==> thickened circular muscle layer==> narrowing of lumen ==> increased rigidity/decreased compliance

Question 22

How is segmentation of colon altered in diverticulosis?

What about nerve cells?

Answer 22

There is disordered colonic motility with an increase in segmental contractile activity

There are fewer glial cells and ICCs

Question 23

What alterations in NTs are seen in diverticular disease? What is the effect?

Answer 23

Increased serotonin/Ach (excitatory)
Decreased NO/vasoactive intestinal peptide (inhibitory)

Result is increased motility and colonic pressures

Question 24

What factors are important in developing symptoms in diverticulosis? (3)

Answer 24

Diet– low fiber, high fat/red meat
Lack of physical activity
Obesity

Question 25

What are the diverticular diseases? (3)

Answer 25

Diverticulitis=inflammation/infection of diverticulum
Segmental colitis associated with diverticulosis (SCAD)= chronic; IBS precursor
Symptomatic uncomplicated diverticular disease= persistent GI symptoms without colitis/diverticulitis

Question 26

What is general progression of diverticulitis?

Answer 26

Erosion of diverticular wall
Inflammation
Focal necrosis
Perforation
If contained, can lead to obstruction, stricture or fistula. 
If not contained, peritonitis

Question 27

What is cause of bleeding in diverticulitis?

Answer 27

As diverticulum herniates, blood vessel responsible for wall weakness separates from bowel