ambirnba's version from 2015-04-14 03:48

Section 1

Question Answer
colon histologyColon has crypts of Lieberkühn but no villi; abundant goblet cells.
irritable bowel syndrome diagnosis≥ 2 of the following: Pain improves with defecation 􏰂 Change in stool frequency 􏰂 Change in appearance of stool
what is Hirschprung’s disease?defective relaxation and peristalsis of rectum and distal sigmoid colon
Hirschprung’s disease is due tocongenital failure of ganglion cells (neural crest-derived) to descend into myenteric and submucosal plexus
Myenteric (Auerbach) plexus is located ____ and regulates ___.between the inner circular and outer longitudinal muscle layers of the muscularis propria; motility
submucosal (Meissner) plexus is located ____ and regulates ___ (3)in the submucosa; blood flow, secretions, and absorption.
main clinical feature of Hirschprung’s diseaseassive dilatation (megacolon) of bowel proximal to obstruction
treatment of Hirschprung’s diseaseTreatment involves resection of the involved bowel; ganglion cells are present in the bowel proximal to the diseased segment.
angiodysplasia usually arises in the ___ and ___ due to ______ecum and right colon due to high wall tension
one way that angiodyplasia presentsRupture classically presents as hematochezia in an older adult.
True diverticula involve ____all layers of the structure, including muscularis propria and adventitia.
False diverticula do not involve ____ or______. False diverticula, in the GI tract for instance, involve only the ______ (2).muscular layers; adventitia; submucosa and mucosa
diverticula arise where_____. ______ is the most common locationhere the vasa recta traverse the muscularis propria (weak point in colonic wall); sigmoid colon is the most common location.
appendicitis pathophysRelated to obstruction of the appendix by lymphoid hyperplasia (children) or a fecalith (adults)
A pseudomembrane (pseudomembranous colitis) is a layer of ___ (2) overlying sites of mucosal injury. (“True” mucous membranes are___.)inflammatory cells and debris; epithelial
“Mushroom Cloud” histologypseudomembranous colitis
very prevalent colon pathology who's pathophysiology is not well understoodIrritable Bowel Syndrome
____ hemorrhoids are above ___ line. _____ hemorrhoids are below this lineinternal. pectinate. external
Hyperplastic polyps are due to ___; classically show a ___ on microscopyhyperplasia of glands; 'serrated' appearance
juvenile polyposis syndrome. genetics? age? type of polyps in colon, stomach, small bowel? increases risk for?autosomal dominant. hamartomatous polyps. risk of colorectal cancer.
hamartomatous polyps. neoplastic? architecture? associated with?Non-neoplastic; solitary lesions do not have a significant risk of malignant transformation. Growths of normal colonic tissue with distorted architecture. Associated with Peutz-Jeghers syndrome and juvenile polyposis.

Section 2

Question Answer
Peutz-Jeghers syndrome. presentation. geneticsHamartomatous (benign) polyps throughout GI tract and mucocutaneous hyperpigmentation (freckle-like spots) on lips, oral mucosa, and genital skin; autosomal dominant disorder
Peutz-Jeghers syndrome. increases risk forolorectal, breast, and gynecologic cancer
adenomatous polyps are due to ___neoplastic proliferation of glands (
isorder characterized by 100s to 1000s of adenomatous colonic polyps FAMILIAL ADENOMATOUS POLYPOSIS (FAP)
FAMILIAL ADENOMATOUS POLYPOSIS due to nherited APC mutation ( adenomatous polyposis coli
FAMILIAL ADENOMATOUS POLYPOSIS treatmentColon and rectum are removed prophylactically; otherwise, almost all patients develop carcinoma by 40 years of age.
Gardner syndrome isFAP with fibromatosis and osteomas.
Turcot syndrome FAP with CNS tumors
Turcot syndrome mneumonicFAP + malignant CNS tumor. Turcot = Turban.
lynch syndrome geneticsAutosomal dominant mutation of DNA mismatch repair genes with subsequent microsatellite instability.
______-sided carcinoma usually grows as a 'napkin-ring' lesion;left
two distinct pathways are believed to be involved in the pathogenesis of colonic adenocarcinoma:-APC/B-catenin pathway -DNA mismatch repair pathway
microscopic morphology. crohns: _________ ulcerative colitis: _________crohns: Noncaseating granulomas and lymphoid aggregates (Th1 mediated). ; ulcerative colitis: Crypt abscesses and ulcers, bleeding, no granulomas (Th2 mediated).

Section 3

Question Answer
sulfasalazine: mechanism(1) sulfa group (antibacterial) (2) 5-ASA group (5-aminosalicylic acid (anti-inflammatory).
sulfasalazine: clinical useUlcerative colitis, Crohn disease (colitis component).
why we don't like the sulfa group in sulfasalazineNausea, heartburn, headache, diarrhea Renal failure Liver failure Skin rashes Reduced sperm count
mesalaminewas constructed by removing the sulfa moiety and leaving the active 5-ASA No sulpha side effects!
mesalamine mode of actiontopical
azathioprine mechanism. pathway. and why is it anti-inflamatory?inhibit de novo purine synthesis. “azathio- purine.” Inhibits lymphocyte proliferation by blocking nucleotide synthesis.
methotrexate mechinhibit dihydrofolate reductase (which converts DHF to THF)
infliximab and adalimumab mechanismtherapeutic antibody against Soluble TNF-α
crohn disease treatmentCorticosteroids, azathioprine, antibiotics (e.g., ciprofloxacin, metronidazole), infliximab, adalimumab.
ulcerative colitis treatment5-aminosalicylic preparations (e.g., mesalamine), 6-mercaptopurine (azathioprine), infliximab, colectomy.
Laxativesproduce soft-formed stool over time
Catharticsquickly evacuates bowels
laxatives: bulk forming agents: mechbind/absorb water and ions in lumen, which increases water content and mass in GI. Fermentation of bulk agent in gut pulls water & ions into GI
osmotic laxatives. mechProvide osmotic load to draw water into the GI lumen.
milk of magnesia. osmotic cathartic. Magnesium salts: magnesium citrate, magnesium sulfate, magnesium hydroxide
stimulant/ contact laxativecan be applied rectally. increases secretion of ions and water into bowel lumen increases colonic motility (irritate bowel and/or stimulate enteric nervous system)
castor oil is an example ofa stimulant/contact laxative
STIMULANT/CONTACT LAXATIVES side effectsMost often abused laxatives; addictive; abuse can lead to “cathartic colon”
stool softeners mechEmollient agents that act as lubricants. Become emulsified with stool and soften it.
3 classes of antidiarrhealsbulk forming agents, adsorbent/demulcents, opiates
opiates mode of actionslow GI motility (↓ ACh release). Act via μ and δ opiate receptors in the GI tract.
Loperimide (Imodium) is an example of opiates
Alosetron (Lotronex) is a 5-HT3 antagonist that blocks receptors on enteric neurons, thereby reducing distention and inhibiting colonic motility, thereby reducing _____-associated pain. Its main approved use is in _____, specifically in _____.irritable bowel syndrome; “diarrhea- predominant” IBS; women
tegaserod is used for ______. it's general mechanism:Used for “constipation-dominant” IBS (primarily for women). Promotes bowel function (peristalsis, motility)
Lubiprostone is similar to tegaserod
LinaclotideFor “constipation-dominant” IBS and idiopathic chronic constipation (in women and men)