GI 2 Flashcards
persistent herniation of bowel into umbilical cord
omphalocele (due to failure of herniated intestines to return to body cavity during development)
MOA of rifaximin vs lactulose in hepatic encephalopathy
rifax - decreae intestinal ammonia production
lactulose - lowers colonic pH and increases conversion of ammonia to ammonium
cdiff toxin MOA
toxin a - brush border cuasing diarrhea
toxin b - depolymerazation actin filaments, pseudomembranous colitis
two types of chronic gastritis
chronic h pylori
chronic autoimmune gastritis
MOA curling ulcer
usually from burns
burns cause hypovolemia which will shunt blood away from stomach leaving it prone to ischemia of mucosa
how does inreased ICP cause acute gastritis
increased ICP will increase vagal stimulation which will increase Ach which will increase H+ by parietal cells
where are parietal cells located
primarily in fundus and body
autoantibodies to parietal cells and intrinsic factor
chronic autoimmune gastritis
lab values in chronic autoimmune gastritis
decreased acid (achlorhydria) so G-cells will be stiulated to make gastrin (increased gastrin) this will cause G cell hyperplasia which will increase risk for gastric cancer
hematologic complication of chronic autoimmune gastritis
pernicious anemia
MCC cause for vitb12 deficiency
goblet cells in stomach?
sign of intestinal metaplasia
mcc site of Hpylori?
antrum of stomach
they don’t invade gastric mucosa they just sit on epithelium
h pylori increass risk for developent of which cancer
MALT lymphoma (marginal zone lymphoma, b cell)
how to check for eradication of h pylori
negative breath test or lack of stool antigen
MCC site of peptic ulcer disease
MCC proximal duodenum or distal stomach
etiology PUD
hpylori
ZE syndrome
how does duodenal ulcer look on biopsy
ulcer with hypertrophy of Brunner glands
how does duodenal present
epigastric pain that IMPROVES with meals
complications of posterior wall ulcer
gastroduodenal artery bleed or ACUTE PANCREATITIS
etiology gastric ulcer
hpylori
nsaids
bile reflux
how does gastric ulcer present
epigastric pain that WORSENS with meals
complication of gastric ulcer
left gastric artery
feature of benign ulcer
small, punched out, normal looking margins ( no piling up of mucosa)
feature malignant ulcer
large, not punched out, piling up margins
two types of gastric adenocarc
intestinal or diffuse
site of intestinal gastric cancer
lesser curvature of antrum
risk factors for intestinal type
intestinal metaplasia, nitrosamines (smoked foods),
what blood type is intestinal type gastric cancer
type A
signet ring cells diffusely infiltrating gastric wall causing desmoplasia…thickening
diffuse type gastric cancer
signet ring cells filled with what
mucin (pushes out nucleus)
which type of gastri c cancer is associated with stomach wall grossly thickened
diffuse type
how does gastric carcinmoa preseent
weight less, abd pain, early satiety,
ACANTHOSIS NIGRACANS AND LESER TRELAT SIGN (
dozens of seborrhic keratosis that arise all of a sudden associated with what cancer
gastric cancer
leser trelat sign
which lmyphnode is typically involved in gastric cancer
left supraclavicular (virchow node)
where does diffuse type like to metastasize
ovaries (bilateral)…will show abundant mucin producing signet cells
(Krukenbug)
where does intestinal type like to metastasize
periumbilical region (nodule sister mary joseph nodule
failure of vitelline duct to involute
meckel diverticulum
meconium coming out through umbilicus
meckel diverticulum
rule of 2s meckel
2% populatio
2inches long
2 ft from ileocecal valve
2 years of life (presents within)
why does meckel diverticulum cause bleeding
ectopic gastric mucosa tha tproduces acid which will cause bleeding
MCC site volvulus
elderly - sigmoid colon
young adult - cecum
proximal segment telescoping into distal segment
intussusception…currant jelly stools
MCC cause of intus in children
lymphoid hyperplasia from viral infection causes terminal ileum to be dragged into cecum
etiology of mesenteric ischemia
blockage of blood flow usually embolus blocking SMA
how does acute mesenteric ischemia present
pain out of proportion
currant jelly stool
decreased bowel sounds
HLA association in celiac
HLA Dq 2 and dq 8
ate too much celiac at dairy queen
most pathologic component of gluten is
gliadin
skin finding in celiac
dermatitis herpetiformis (due to IgA deposition at tips of dermal papillae)
lab findings in celiac
IgA antibodies against endomysium, TTG or gliadin igA
how to dx celiac if iga deficiency
check IgG antiboides
biopsy of celiac
flattening of villi, hyperplasia of (deeper crypts) crypts and increased intraepithelial lymphocytes
most damage seen where in celiac?
duodenum
refractory celiac even with good dietary control associated with what
small bowel carcinoma and T cell lymphoma!!!!!!
EATL enteropathy assocaited T cell lymphoma
how to differentiate tropical sprue with celiac?
tropical sprue damages JEJUNM AND ILEUM (celiac is in duodenum), it is usually preceded by infectious diarrhea and responds to antibiotics…also seen in tropical regions duh
where do we absorb folic acid
jejunum
where we do absorb b12
ileum
where does whipple disease happen
small bowel lamina propria
GI complication of whipple
fat malabsorption and steatorrhea
foamy macrohapges is lamina propria
whipple disease
PAS positive
what other symptoms besides GI can whipple present with
CAN
cardiac symptoms, arthralgias, neurologic symptoms
what happens if you knock out apob48
can’t make chylomicrons (malabsorption)
what happens if you knock out b-100
absent plasma VLDL and LDL
positive chromogranin tumor low grade
carcinoid tumor
where does carcinoid tumor usually invade
small bowel
how does carcinoid tumor cause carcinoid syndrome if it started in GI
it must metastasize to liver so it can dump serotonin directly into hepatic vein…this can lead to systemic effects esp in heart (right sided valvular )fibrosis…tricuspid regurg and pulmonary valve stenosis))
what breaks down serotonin into 5hiaa
MAO in LIVER and lungs
MOA diphenoxylate
mu opoid antidiarrheal drugs to slow motility
MCC appendicitis children
lymphoid hyperplasia
fecalith in adults
adverse biliary effect of mu opoid analgesics
mu opoid analgesics cause contraction of smooth muscles in sphincter of Oddi leading to increased pressures in CBD adn gall bladder (biliary colic)
MCC site diverticula
where vas recta transvese muscularis propria (weak point)…SIGMOID COLON
complication of diverticla
rectal bleeding, divertaiculitis, FISTULAS (something colonic fistula)
MCC site of angiodysplasia
cecum and right colon
due to high wall tension (as opposed to high stree on left which causes diverticula)
thin walled blood vessels in nasopharynx and GI tract
hereditary hemorhagic telangiectasia
where is MCC site ischemic colitis
splenic flexure (most distal from SMA)
mcc cause ischemic colitis
atherosclerosis of SMA
when does ischemic colitis pain present
postprandial (when muscle demand of colon goes up)
MCC colonic polyp
hyperpalstic (MCC) and adenomatous
prognosis of hyperplastic polyp
great! has no malignant potential, usually arise in left colon (recto sigmoid) “serrateD”
prognosis adenomatous polyp
PREMALIGNANT (ADENOMA-CARCINOMA SEQUENCE)
mutations assocaited with adenomatous polyp
APC, KRAS, p53 mutation and increased COX expression
in that order!
APc.(chrome 5) creates risk for polyps (tumor suppressor).
this is the gene involved in FAP…
kras allows for formation of polyp
p53 allows polyp to turn into carcinoma (needs COX, so aspirin blocks this ;))
increasd risk of colonic polyp malignancy
size greater than 2 cm
sessile growth (unpedunculated, grows directly on wall)
VILLOUS histology is the VILLAIN
knock out of APC utation on chrom5
FAP, AD disorder…100-1000 adenomatous polyps
FAP with fibromatosis and osteomas
gardner syndrome
turcot syndrome
FAP with CNS tumors (medulloblastoma and gliaoma)
numerous hamartomas throughout GI tract with hyperpigmented mouth, lips, hands, genitalia
putz jeghers AD
increase risk for colorectal, breast, and gyn cancer
adenoma carcinoma sequence
APC -> kras -> p53 (+COX)
besides adenoma cacinoma sequence what othe rmolecularpathway an lead to colon cancer
micosatellite instability (mutation of DNA mismatch repair)…seen in HNPCC
HNPCC Lynch assocaited with higher risk of…
colorectal, ovarian, and endometrial
napkin ring lesion, decreased stool caliber, pencilling, blood streaked stool
left sided carcinoma
IDA, raised lesion, vague pain
right sided carcinoma
patient with strep bovis endocarditis…what to do next
COLONOSCOPY
how does colorectal cancer appear on barium enema
“apple core” lesion
what marker to detect recurrence and treatment response of colon cancer
CEA
venous component of internal vs external hemhorroids
internal - middle and superior rectal veins which communicate with internal iliac and inferior mesenteric veins
external - inferior rectal vein into interpudendal vein which communicates with internal iliac
painless lower GI bleeding in child…how to confirm dx
suspect meckel’s
dx with Tcpertechnetate scan (searches for sites of ectopic gastric mucosa….i.e. parietal cells in areas where they aren’t supposed to be)
how is copper removed form body
majority of copper absorbed in stomach and duodenum bound to albumin and taken to liver wehre it is incorporated to form ceruloplasmin which is then secreted into bBILE AND STOOL
treatment for narcolepsy
daytime stimulants (amphetamines MODAFINIL) and night time sodium oxybate
which combo of cholesterol medications results in greatest risk for myopathy
STATIN AND FIBRATES (lesser extent statins and niacin/ezetimibe)p
pathogenesis of alcohol induced hepatic steatosis
excess NADH produciton due to alcohol dehydrogenase and aldehyde dehydrogenase IMPAIRS FREE FATTY OXIDATION
MOA lactic acidosis due to mesenteric ischemia
in aerobic metabolism pyruvate is prferentially converted to acety CoA for for oxidative phosphorylation…but ischemia is due to decreased oxygen so pyruvate is shunted to lactate by lactate dehydrogenase leading to lactic acidosis
what two substances can increase cholesterol solubility
bile acids and phospholipds (phosphotidylcholine)
lower levels of these are asssoicated with cholesterol stone formation
MOA mallory weiss
INCREASE IN INTRABDOMINAL PRESSURE
NOT ISCHEMIA
mcc site intusuccesption in children
ileocecal valve region
mcc site anal fissure
posterior midline of anal verge past dentate line
this part is poorly perfused
Pectinate line Pain while pooping. blood on toilet Paper. located Posteriorly because this area is Poorly Perfused
mcc site hpyori infection
gastric antrum (prepyloric area)
how does hepatocellulr carcinoma look
large hepatic mass with multiple satellite lesions
tumor marker HCC
AFP
examples of true diverticula and false diverticula
true - meckel’s, normal appendix
false - zenker’s, diverticuli
which neurons are psudounipolar
cn V VII IX X sensory
spinal posterior root ganglia
where are bipolar neurons found
cochlear and vestibular ganglia of CN VIII and in olfactory nerve and in retina
histologic substance characteristic of neurons found in nerve cell bodies and dendrites
nissl substance (rosettes of polysomes and RER)…role in protein synthesis
regen possible in PNS or CNS
PNS (mediated by schwann cells and endoneurium)
Gastric bypass can lead to small bacterial overgrowth leading to increased production of……
vitamin K and folate
