Small Intestine

Question 1

Which is longer, small bowel or colon?

Answer 1

small bowel 7 meters

colon 1.5 meters

Question 2

Name 4 things that contribute to large surface area of small bowel

Answer 2

1. length
2. folds (plicae circulares)
3. villi
4. microvilli

Question 3

What is a normal villous to crypt ratio?

Answer 3

3 or 5: 1 (crypts are mitotically active and replenish the cells lining the villi as they are lost)

Question 4

As you progress thru the small intestine, absorptive cells decrease in number distally, what do goblet cells do?

Answer 4

increase in number distally

Question 5

Name 4 symptoms of intestinal obstruction

Answer 5

Abdominal pain
Nausea/vomiting
Diarrhea or Constipation
Abdominal distension

Question 6

T/F- intestinal obstruction most often involves the small bowel and most commonly results from herniation, volvulus, intusception, and adhesions

Answer 6

true

Question 7

Herniation results from a weakness or defect in the wall of the pertitoneal cavity (inguinal/femoral canals, umbilicus, surgical scar sites) what happens to small bowel loops when they pass thru these areas?

Answer 7

Small bowel loops (typically) become entrapped

• Incarceration: permanent entrapment
• Strangulation: arterial and venous compromise that can result in infarction

Question 8

What is a volvulus?

Answer 8

Loop of bowel that twists about itself, leads to obstruction and infarction of bowel

Question 9

Intussusception is when a segment of the intestine telescopes into itself, what is the significance of this in older children and adults?

Answer 9

often associated with an intraluminal tumor that serves as the leading point of traction

Question 10

Review the rule of 2’s for Meckels diverticulum

Answer 10

• 2% of the population
• Usually within 2 feet (85 cm) of the ileocecal valve
• ~2 inches long
• 2X as common in males
• Most often symptomatic by age 2

Question 11

What is Meckel’s diverticulum?

Answer 11

failed involution of the vitelline duct (connects the lumen of the developing gut to the yolk sac).

Question 12

Is Meckel’s diverticulum a true or false diverticulum?

Answer 12

True

Question 13

Name 3 complications of Meckel’s diverticulum

Answer 13

1. Bleeding
   - Peptic ulcer due to ectopic gastric epithelium
2. Obstruction
   - Intussusception
3. Tumor (rare)
   - carcinoid

Question 14

What is a true diverticulum (Meckel’s)

Answer 14

blind outpouching of the ileum that has all three layers of the bowel wall (mucosa, submucosa, and muscularis propria)

Question 15

T/F- Meckel diverticulum may contain ectopic pancreatic or gastric tissue and gastric parietal cells may result in peptic ulceration of small intestinal mucosa

Answer 15

true

Question 16

What is the hallmark of malabsorption?

Answer 16

Steatorrhea

Question 17

A patient presents with anemia, chronic diarrhea, bloating, muscle wasting. His physician informs him that he has a small risk of developing enteropathy associated T cell lymphoma and small intestinal adenocarcinoma. What does he have?

Answer 17

celiac disease

Question 18

What are the most sensitive serological tests for celiac disease?

Answer 18

• IgA (or IgG) to tissue transglutaminase (TTG)

- IgA (or IgG) antibodies to deamidated gliadin

Question 19

Most specific but less sensitive serology for celiac?

Answer 19

anti-endomysial antibodies

Question 20

A patient with celiac is negative for serologies tested. Why?

Answer 20

If negative serologies, remember IgA deficiency, which is more common in celiac patients=>Can get titers of IgG to TTG and deamidated gliadin

Question 21

What HLA’s are useful in ruling out celiac?

Answer 21

HLA-DQ2 or HLA-DQ8

Question 22

Why are the duodenum and proximal jejunum most affected by celiac disease?

Answer 22

exposed to highest concentration of gluten from diet

Question 23

Name key histologic findings in celiac disease

Answer 23

• 1st - increased intraepithelial lymphocytes (CD8+ T cells)
• later - crypt hyperplasia, and villous atrophy
• Loss of mucosal and brush-border surface area → malabsorption

Question 24

T/F- giardiasis is common in contaminated water in the midwest and can spread person to person in daycare centers

Answer 24

true

Question 25

Whipples disease is caused by what organism?

Answer 25

Trophyrema whippleii

Question 26

Review symptoms associated with Whipples disease

Answer 26

Gastrointestinal 
-Diarrhea, weight loss, and malabsorption
Extraintestinal (can exist formonths or years before malabsorption)
-Arthritis/arthralgia
-Fever
-Lymphadenopathy
-Neurologic
-Cardiac
-Pulmonary disease

Question 27

What other organism mimics Whipple’s disease histologically?

Answer 27

Cannot tell if it is whipple’s or mycobacterium avium intracellulare without AFB stain!

Question 28

Are malignancies common or uncommon in the small intestine?

Answer 28

uncommon despite the large surface area

Question 29

Where are the most aggressive neuroendocrine tumors of the small bowel found?

Answer 29

jejunum/ileum

Question 30

A pale yellow tumor of the ileum is found. It “knuckles” due to fibrosis. What is it?

Answer 30

ileal neuroendocrine tumor

Question 31

Name 2 vasoactive peptides released in carcinoid syndrome

Answer 31

serotonin

bradykinin

Question 32

If a carcinoid tumor is able to bypass the metabolic effects of hepatocytes, what symptoms would a person have?

Answer 32

flushing, wheezing, diarrhea

Question 33

A patient has duodenal lymphoma, what should you check for next?

Answer 33

celiac disease

Question 34

Acute appendicitis is most common in what age groups?

Answer 34

adolescents and young adults

Question 35

Symptoms of appendicitis?

Answer 35

• Pain starts periumbilically then localizes to the right lower quadrant
• Nausea/vomiting, low-grade fever, and a mildly elevated peripheral white cell count

Question 36

What is the most common tumor of the appendix?

Answer 36

low grade neuroendocrine tumor (almost always benign)

Question 37

A mucocele can also occur in the appendix, what can cause this?

Answer 37

-May result from an obstructed appendix containing inspissated mucin
-Can be from a neoplastic process
(When transmural can result in pseudomyxoma peritoneii (abdomen fills with tenacious, semisolid mucin))