GIT: Large Intestine Flashcards
describe Hirschsprung Disease
- 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)
there is an absence of ____ and ____ in Hirschsprung disease
there is an absence of ganglion cells in Meissner (submucosa) and Auerbach (myenteric) plexuses in Hirschsprung disease
Hirschsprung disease is associated with ____
Hirschsprung disease is associated with Down Syndrome
(RET mutation found in both)
describe the pathogenesis of Hirschsprung disease
in Hirschsprung disease, there is a defect in ____
in Hirschsprung disease, there is a defect in migration and survival of neuroblasts
describe the clinical features of Hirschsprung disease
- delayed passage of meconium
- constipation
- abdominal distension
- diagnosed by rectal biopsy
list the complications of Hirschsprung disease
- complication:
- enterocolitis
- perforation and peritonitis
describe the pathogenesis of diverticular disease
- lack of dietary fiber leads to sustained bowel contractions and increased luminal pressure
- herniation of colonic wall at sites of focal defects
diverticular disease pathogenesis:
lack of ___ leads to sustained bowel contractions and increased ____ → herniation
lack of dietary fiber leads to sustained bowel contractions and increased intraluminal pressure → herniation
list the 2 types of idiopathic inflammatory bowel disease
chronic relapsing, inflammatory disorder
- 2 main types
- ulcerative colitis
- Crohn disease
describe ulcerative colitis
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
ulcerative colitis starts in ____
ulcerative colitis starts in the rectum
name the condition in the image and describe the image
ulcerative colitis
sharp demarcation of abnormal from the neighboring normal
name the condition in the image and describe the image
ulcerative colitis
pseudopolyps can be seen
describe Crohn disease
- ileal and colonic involvement
- skip lesions
- transmural inflammation, granulomas
- fissuring ulcers, fistula, strictures
- upper GI involvement and extraintestinal manifestations
ulcerative colitis is associated with ____
ulcerative colitis is associated with primary sclerosing cholangitis
ulcerative colitis has an association with HLA-____
ulcerative colitis has an association with HLA-DRB1
explain the etiology of pseudopolyps in ulcerative colitis
isolated islands of intervening regenerating mucosa bulge, creating pseudopolyps
Crohn disease is associated with HLA- ____
Crohn disease is associated with HLA- DR7 and DQ4
list the extraintestinal manifestations of IBD
- 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
fistulas are associated with (Crohns or UC)?
fistulas are associated with Crohns disease
describe the layers affected in UC vs. Crohns
UC = mucosa + submucosa
Crohns = all layers = transmural
describe amoebic colitis
- 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
describe the image
describe the differences between TB and Crohn’s
list causes of C. difficile colitis
- clindamycin, ampicillin, cephalosporin and amoxicillin
- can occur in patients with Hirschsprung
- can occur during IBD relapse
describe the pathogenesis of pseudomembranous colitis
- 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
list clinical features of ischemic bowel disease
acute ischemic colitis can be caused by ____
acute ischemic colitis can be caused by E. coli
toxins lead to endothelial injury and hemorrhagic colitis
describe causes of eosinophilic colitis
-
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
“older women with watery diarrhea” = which condition?
microscopic colitis
