128b Histo of small bowel disorders

Question 1

small intestine mucosa components - contents and ratio

Answer 1

villi - absorptive cells&raquo_space; goblet cells

crypts - stem cells, paneth cells (protective fxn), neuroendocrine cells, goblet cells

Question 2

what is the middle of the villi? what does it contain?

Answer 2

lamina propria - blood vessels, lacteals, lymphocytes

Question 3

is there normally inflammatory cells in small bowel?

Answer 3

Yes, normally a lot of inflammatory cells in lamina propria

Question 4

location of goblet cells in small intestine, fxn

Answer 4

crypts and villi

secrete mucin - protection and provide the material for uptake of nutrients

Question 5

small intestine - crypt cell functions

Answer 5

produce ions and water
IgA
antimicrobial peptides (paneth cells)
stem cells

Question 6

uptake of macromolecules in small intestine?

Answer 6

via specific receptors on suface epi cells - for example, B12- intrinsic factor receptor in ileum (only segment for IF-B12 uptake)

Question 7

Whipple’s Disease - cause, bacteria, endo/histo, presentation, treatment

Answer 7

systemic bacterial disease with small intestine involvement

gram positive bacillus - T. Whippelii

dilated, thick intestine
lamina propria contains foamy macrophages filled with bacteria (PAS+)

Cardiac valves, Arthralgias, Neurologic + weight loss, malabsorption (Foamy Whipper cream in a CAN)

Rx - antibiotics highly effective (1 year)

Question 8

Celiac Disease - genetics, cause, what age does it present, symptoms, histo/endo, complications, labs

Answer 8

HLA-DQ2/4

autoimmune antibodies to gliadin –> T-cell activation –> small bowel damage–> loss of villi—>malabsorptive disease

3 years when cereal is introduced; peaks at 20-40

malabsorption: Diarrhea - large, bulky, foul-smelling –> weight loss and nutrient deficiency

flat mucuosa (loss of villi) and T-cells (CD-8)

cancer - T-cell lymphoma and adenocarcinoma

anti-endomysial abs
anti-tissue transglutaminase abs
anti-gliadin abs

Question 9

Peutz-Jeghers syndrome - findings/location, genetics, histology, clinical complications

Answer 9

polyps in jejunum + mucocutaneous pigmentation

Genetics - AD of STK11/LKB1 gene

intestinal lobulated polyps with branches of smooth muscle

hemorrhage, intussusception, malignancies (not from polyps though)

Question 10

Crohn’s disease - cause, findings, location, symptoms, endo/histo, complications

Answer 10

unknown cause but immune mediated

chronic inflammatory bowel disease w/ non-caseating granulomas

terminal illeum - sometimes colon too (can occur anywhere in GI tract though)

diarrhea, fever, LQP, anorexia

skip lesions with irregular linear ulcers
cobble stone pattern
transmural inflammation

strictures–> obstruction
perforation and fistulas
polyarthritis
akylosing spondylitis

Question 11

neuroendocrine cells in the gut - EM appearance, neoplasms and appearance, locations/numbers

Answer 11

EM- granules

“carcinoids” - tumor cells are small and uniform with round nuclei and granular eosinophilic cytoplasm; low malignant - potential but low

small intestine have multiple tumors, appendix and rectume - single; IHC staining

Question 12

carcinoid syndrome - cause, symptoms

Answer 12

5HT production

flushing, asthma, diarrhea, right side heart failure if spread to liver (where 5HT is metabolized)

Question 13

appendicitis - pathogenesis, symptoms

Answer 13

fecal material, lymphoid hyperplasia –> luminal obstruction –> increased P, vascular compromise, bacterial overgrowth

Acute LRQ pain (diffuse –> McBurney’s point), rebound tenderness, nausea, fever