GIT: Large Intestine

Question 1

describe Hirschsprung Disease

Answer 1

• most common cause of congenital intestinal obstruction
• associated with Down Syndrome
• absence of ganglion cells in Meissner (submucosa) and Auerbach (myenteric) plexuses
• rectum is always affected
• dilatation and hypertrophy proximal to aganglionic segment (congenital megacolon)

Question 2

there is an absence of ____ and ____ in Hirschsprung disease

Answer 2

there is an absence of ganglion cells in Meissner (submucosa) and Auerbach (myenteric) plexuses in Hirschsprung disease

Question 3

Hirschsprung disease is associated with ____

Answer 3

Hirschsprung disease is associated with Down Syndrome

(RET mutation found in both)

Question 4

describe the pathogenesis of Hirschsprung disease

Answer 4

Question 5

in Hirschsprung disease, there is a defect in ____

Answer 5

in Hirschsprung disease, there is a defect in migration and survival of neuroblasts

Question 6

describe the clinical features of Hirschsprung disease

Answer 6

• delayed passage of meconium
• constipation
• abdominal distension
• diagnosed by rectal biopsy​

Question 7

list the complications of Hirschsprung disease

Answer 7

• complication:
  
  • enterocolitis
  • perforation and peritonitis

Question 8

describe the pathogenesis of diverticular disease

Answer 8

• lack of dietary fiber leads to sustained bowel contractions and increased luminal pressure
• herniation of colonic wall at sites of focal defects

Question 9

diverticular disease pathogenesis:

lack of ___ leads to sustained bowel contractions and increased ____ → herniation

Answer 9

lack of dietary fiber leads to sustained bowel contractions and increased intraluminal pressure → herniation

Question 10

list the 2 types of idiopathic inflammatory bowel disease

Answer 10

chronic relapsing, inflammatory disorder

• 2 main types
  
  • ulcerative colitis
  • Crohn disease

Question 11

describe ulcerative colitis

Answer 11

diffuse involvement starting in the rectum and restricted to colorectum

• histology:
  
  • mucosal and submucosal involvement
  • architectural distortion
  • dense chronic inflammation with basal plasmacytosis
  • cryptitis, crypt abscesses
  • no granulomas

Question 12

ulcerative colitis starts in ____

Answer 12

ulcerative colitis starts in the rectum

Question 13

name the condition in the image and describe the image

Answer 13

ulcerative colitis

sharp demarcation of abnormal from the neighboring normal

Question 14

name the condition in the image and describe the image

Answer 14

ulcerative colitis

pseudopolyps can be seen

Question 15

describe Crohn disease

Answer 15

• ileal and colonic involvement
• skip lesions
• transmural inflammation, granulomas
• fissuring ulcers, fistula, strictures
• upper GI involvement and extraintestinal manifestations

Question 16

ulcerative colitis is associated with ____

Answer 16

ulcerative colitis is associated with primary sclerosing cholangitis

Question 17

ulcerative colitis has an association with HLA-____

Answer 17

ulcerative colitis has an association with HLA-DRB1

Question 18

explain the etiology of pseudopolyps in ulcerative colitis

Answer 18

isolated islands of intervening regenerating mucosa bulge, creating pseudopolyps

Question 19

Crohn disease is associated with HLA- ____

Answer 19

Crohn disease is associated with HLA- DR7 and DQ4

Question 20

Answer 20

Question 21

list the extraintestinal manifestations of IBD

Answer 21

• seen in both CD and UC; can develop even before the onset of GI signs and symptoms
  
  • migratory polyarthritis
  • sacroileitis
  • ankylosing spondylitis
  • erythema nodosum
  • clubbing of finger tips
  • primary sclerosing cholangitis

SPACEM

Question 22

fistulas are associated with (Crohns or UC)?

Answer 22

fistulas are associated with Crohns disease

Question 23

describe the layers affected in UC vs. Crohns

Answer 23

UC = mucosa + submucosa

Crohns = all layers = transmural

Question 24

describe amoebic colitis

Answer 24

• caused by Entamoeba histolytica
• parasitic infection (protozoan)
• fecal-oral route
• may resemble IBD on biopsy
• chronic destructive colitis with flask-shaped ulcers
• may involve liver, lungs, brain
• treated with anti-parasitics

Question 25

describe the image

Answer 25

Question 26

describe the differences between TB and Crohn’s

Answer 26

Question 27

list causes of C. difficile colitis

Answer 27

• clindamycin, ampicillin, cephalosporin and amoxicillin
• can occur in patients with Hirschsprung
• can occur during IBD relapse

Question 28

describe the pathogenesis of pseudomembranous colitis

Answer 28

• fibrinopurluent-necrotic debris (pseudomembranes)
  
  • surface epithelium denuded
  • superficially damaged crypts distended by mucopurulent exudate which erupts to form a mushrooming cloud
  • coalescence of these clouds leads to pseudomembrane formation

Question 29

list clinical features of ischemic bowel disease

Answer 29

Question 30

acute ischemic colitis can be caused by ____

Answer 30

acute ischemic colitis can be caused by E. coli

toxins lead to endothelial injury and hemorrhagic colitis

Question 31

describe causes of eosinophilic colitis

Answer 31

• allergy
  
  • cow’s milk protein allergy
• parasites
• iatrogenic
  
  • drugs, radiation
• collagen vascular diseases
  
  • rheumatoid arthritis, Churg-Strauss syndrome
• inflammatory bowel disease
• tumor or tumor-like conditions
  
  • leukemia/lymphoma
  • hypereosinophilic syndrome

Question 32

“older women with watery diarrhea” = which condition?

Answer 32

microscopic colitis