GI Pathology III: Small Intestine

Question 1

What are the clinical features and histological findings in Hirschsprung disease?

Answer 1

Constipation with lack of ganglion cells on histology

Question 2

What is the infectious agent in pseudomembranous colitis?

Answer 2

C. difficile

Question 3

What is the common parasitic infection that presents with bloody diarrhea?

Answer 3

E. histolytica

Question 4

What is the gene mutation in familial adenomatous polyposis (FAP)?

Answer 4

Autosomal dominant mutation of the APC gene

Question 5

Plicae Circularis

Answer 5

Plicae circularis are folds of the mucosa and submucosa

Question 6

Paneth Cells

Answer 6

Function in cell defense in the intestine. Paneth cells have lysozymes and defensins.

Question 7

What are features specific to the duodenum?

Answer 7

Brunner’s Glands

Question 8

What are features specific to the ileum?

Answer 8

Peter’s Patches

Question 9

What is the main function of the large intestine?

Answer 9

Absorption of water

Question 10

Where is Meissner Plexus located?

Answer 10

In the submucosa

Question 11

Where is Auerbach’s Plexus located?

Answer 11

Between the circular and longitudinal muscle in the muscularis propria

Question 12

Intussusception

Answer 12

Telescoping of bowel segment into distal segment often at the ileocecal junction

Question 13

Volvulus

Answer 13

Twisting of the bowel around its mesentery leading to obstruction and can compromise blood flow

Question 14

Where does volvulus occur in children? Adults?

Answer 14

Children - midgut

Adults - sigmoid

Question 15

Necrotizing Entercolitis

Answer 15

Most common GI emergency in premature neonates with acute necrotizing inflammation of the small and large bowels

Question 16

Meckel’s Diverticulum

Answer 16

Disease of 2’s

• 2:1 male to female
• 2 major complications are pain with inflammation and hemorrhage with ulcer

Question 17

Who is most affected by Hirschsprung disease?

Answer 17

Males in a 4:1 ratio

Question 18

What is Hirschsprung disease associated with?

Answer 18

Down syndrome

Question 19

What can pancreatic insufficiency be caused by and what does it result in the malabsorption of?

Answer 19

• Pancreatitis/Cancer

It will affect the absorption of fat and vitamins A, D, E and K

Question 20

What is the most common type of disaccharide deficiency and what are the symptoms?

Answer 20

Lactase. Osmotic diarrhea.

Question 21

Abetalipoproteinemia

Answer 21

Decreased synthesis of apolipoprotein B which decreases the amount of chylomicrons leading to the accumulation of fat and cholesterol in the enterocytes - presents as failure to thrive

Question 22

Celiac Disease

Answer 22

Autoimmune disorder that results in the damage of small intestinal lining when gluten is eaten

Question 23

Who is celiac disease seen most often in?

Answer 23

Caucasians and Europeans

Question 24

What is the pathogenesis of celiac disease?

Answer 24

Gluten is converted to gliadin which is deaminated by TTG and is presented to a T cell. The T cell will attack the enterocytes and activate B-cells leading to Ab formation

Question 25

What happens to the villi in celiac disease?

Answer 25

They are lost from the inflammation

Question 26

What are the prominent cells seen in celiac disease?

Answer 26

CD8+ T cells

Question 27

What are the important tests for celiac disease?

Answer 27

• Serologic test for TTG and gliadin Ab

- Biopsy showing villous atrophy

Question 28

What are some bacterial causes of enterocolitis?

Answer 28

• Cholera
• Campylobacter
• Yersinia
• E. coli
• Shigella
• Salmonella

Question 29

What are some viral causes of enterocolitis?

Answer 29

• Norovirus

- Rotavirus

Question 30

What are some of the parasitic causes of enterocolitis?

Answer 30

• Nematodes
• Flatworms
• Protozoans (Giardia, E. histolytica)

Question 31

What is the histological characteristic of E. histolytica infection?

Answer 31

Flask shaped ulcer

Question 32

What is the histological finding in pseudomembranous enterocolitis?

Answer 32

Mushroom pseudomembrane

Question 33

Who is generally affected by collagenous enterocolitis?

Answer 33

Middle to older age women

Question 34

What is the histological finding of collagenous enterocolitis?

Answer 34

Presence of collagen (blue with trichrome stain)

Question 35

What is lymphocytic enterocolitis associated with?

Answer 35

Autoimmune diseases

Question 36

What will be seen on histology of lymphocytic enterocolitis?

Answer 36

Lymphocytes

Question 37

Whipple Disease

Answer 37

Rare and found in men more commonly. It is caused by Tropheryma whippleli and is engulfed by macrophages where they fill the lamina propria and distend it.

Question 38

Crohn’s Disease

Answer 38

It is a disordered response to bacteria. Usually affects the terminal ileum but can affect any part of the GI tract and it will show with strictures and serosal creeping fat.

Question 39

What is seen on histology of Crohn’s disease?

Answer 39

• Transmural inflammation - full thickness of the wall

- Ulceration and non-caseating granulomas

Question 40

Ulcerative Colitis

Answer 40

Autoimmune with relapsing attacks of bloody mucoid diarrhea with pain with diffuse continuous inflammation

Question 41

What layers does ulcerative colitis affect?

Answer 41

Only the mucosa and submucosa, and there are NO non-caseating granulomas

Question 42

What is the diarrhea of Crohn’s like?

Answer 42

Non-bloody

Question 43

What is the diarrhea of ulcerative colitis like?

Answer 43

Bloody

Question 44

What is a distinguishing feature in the how the intestines are affected in Crohn’s VS ulcerative colitis?

Answer 44

Crohn’s will have skip areas and thus is focal.

UC is continuous and therefore diffuse.