10.5 Small Bowel

Question 1

Duodenal Atresia

Answer 1

Failure of the small bowel to canalize

Question 2

What is duodenal atresia associated with?

Answer 2

Down Syndrome

Question 3

What are the clinical features of duodenal atresia?

Answer 3

• Polyhydramnios
• Distension of the stomach and duodenum
• Bilious vomiting

Question 4

Meckel Diverticulum

Answer 4

Outpouching of all 3 layers of the bowel wall due to the failure of the vitelline duct to involute
-> DISEASE OF 2’s

Question 5

Volvulus

Answer 5

Twisting of the bowel along its mesentery result in obstruction and infarction

Question 6

What are the common locations of volvulus in the elderly and young adults?

Answer 6

Elderly - sigmoid colon

Young adults - cecum

Question 7

Intussusception

Answer 7

Telescoping of proximal segment of bowel into a distal segment

Question 8

Lactose Intolerance

Answer 8

Decreased function of the lactase enzyme in the brush border that causes dissension and diarrhea with ingestion of milk products

Question 9

Celiac Disease

Answer 9

Immune mediated damage of small bowel

Question 10

What is the most pathogenic component of gluten?

Answer 10

Gliadin

Question 11

What the pathogenesis of Celiac’s disease?

Answer 11

Deaminated gladden is presented by APCs via MHC II and helper T cells mediate tissue damage

Question 12

Dermetitis Herpetiformis

Answer 12

Deposition of IgA at tips of dermal papillae - one of the symptoms of Celiac’s disease that resolves with gluten free diet

Question 13

What are the Ab found in Celiac disease?

Answer 13

IgA anti-endomysium, tTG or gliadin

Question 14

What will duodenal biopsy show for Celiac disease?

Answer 14

Flattening of villi with hyperplasia of the crypts

Question 15

What part of the small intestine is most affected by Celiac disease?

Answer 15

Duodenum

Question 16

If there is refractory symptoms in a Celiac patient despite a gluten-free diet what are the possible causes?

Answer 16

• Small bowel carcinoma

- T cell lymphoma

Question 17

Tropical Sprue

Answer 17

Damage to small bowel villi by some unknown agent that results in malabsorption - arises after diarrhea and responds to antibiotics

Question 18

Where is the damage mostly seen in tropical sprue?

Answer 18

Jejunum and ileum

Question 19

Whipple Disease

Answer 19

Systemic tissue damage with macrophages loaded with Tropheryma whippelii - organism remains int hem

Question 20

What is the main site affected by Whipple disease?

Answer 20

Fat malabsorption and steatorrhea

Question 21

Why does fat malabsorption occur in Whipple disease?

Answer 21

Macrophages block chylomicron absorption in the lamina propria

Question 22

Abetalipoproteinemia

Answer 22

Autosomal recessive deficiency of apolipoprotein B-48 and B-100 which leads to defective chylomicron and VLDL and LDL formation

Question 23

Carcinoid Tumor

Answer 23

Low grade malignancy of neuroendocrine cells

Question 24

What is the most common site for carcinoid tumor?

Answer 24

Small bowel

Question 25

What do GI carcinoid tumors often secrete?

Answer 25

Serotonin (5-HIAA in the urine)

Question 26

Carcinoid Heart Disease

Answer 26

Right sided valvular fibrosis which leads to tricuspid
regurgitation and PV stenosis

• Occurs with carcinoid metastasis from the GI to the liver