GI Flashcards
etiology of gastric and duodenal ulcers?
gastric: direct invasion and damage in body of stomach, duodenal: decreased somatostatin, increased gastrin, increased acid
2 actions of fibrates and SE?
fibrate: PPAR-a activator, increased hydrolysis of VLDL and increased beta oxidation of fatty acids, leading to lower triglycerides. can cause gall stones by preventing bile salt formation by inhibiting cholesterol 7 alpha hydroxylase
woman with persistent noninflammatory diarrhea that gets better with somatostatin. diagnosis?
VIPoma
what is enteropeptidase?
a brush border enzyme that activates trypsinogen to trypsin, which aids in lipid and protein digestion
young ish man with pancreatitis, CT shows pancreatic divisum. what is this? explain embryology
ventral bud forms the main pancreatic duct, rest of the pancreas in the dorsal bud. in normal development the buds fuse at 8 weeks, but in pancreatic divisum it remains divided, separate ductal systems–> pancreatitis
why do you get gallstones in crohn’s disease?
bile acid absorption is at terminal ileum, which crohn’s disease affects often. decreased bile acid absorption leads to higher cholesterol:bile acid ratio in bile increases, leading to gallstones
2,3 aVF ST elevations in boy in soccer pain with chest pain, increased serum methionine, what amino acid is essential for this patient?
cysteine. dx is homocysteineuria, the build up of homocysteine causes thrombosis including in the coronary arteries. due to decreased amounts of cystathionine synthase, which prevents cysteine formation from homocysteine.
RTA, seatbelt bruising, and retroperitoneal bleeding. where is the source?
pancreas contusion
infant botulism vs adult botulism
c. botulinism spores ingestion leading to floppy baby and lethargy vs preformed toxin ingestion from canned food
what can be used to test brushborder enzyme function independent of pancreatic activity, in patient with pancreatic resection due to chronic pancreatitis and mass
d-xylose- monosaccharides are readily absorbed. polysaccharides need to be digested by amylase first
multiple hypodense regions in liver, with massive hyperdense area next to it
mets to liver (more common than HCC) and oral contrast in stomach
most common benign mass in liver
cavernous hemangioma- blood filled spaces wth single epithelial layer in the liver
woman with chronic diarrhea that is uncomplicated, started on diphenoxylate, what is that?
its an opioid that slows motility, given tgt with atropine (to prevent addiction) SE is biliary colic because it constricts sphincter of oddi
oral vs intramuscular antibody, which Ig concetntration is markedly different?
IgA
excess mast cells in the skin positive for CD117, KIT, have what effect on GIT?
gastric hypersecretion because of histamine activating the proton
pneumobilia, gallstones and abdo pain and vomiting
gallstone ileus triad, gets stuck in ileum after fistula formation because ileum is the narrowest
how does TPN cause gallstones
decreased CCK production, gallbladder hypomotility
crohn’s disease effect on colonic architecture
thickening of muscularis mucosae, causing strictures, and fat creeping
fingertip ulcers, calcifications, telangiectasias and severe heartburn. dx and mechanism of heartburn?
CREST of systemic sclerosis- fibrous replacement of muscularis of lower esophagus
colon polyp, which has worst prognosis?
lymph node invasion. not lamina propria because its like basement membrane (in-situ) and the lymph drain in muscularis mucosae
signet ring carcinoma what type is this?
diffuse type of gastric carcinoma, linitis plastica because invades the wall because lack of E-cadherin. the other type is infiltrative- glands involvement
fatty cells in the villi of intestinal epithelium, dx
abetalipoproteinemia, cannot make apoB contiaing lipoproteins, which means cannot collect fat from enterocytes
autopsy looks like FAP of the liver, what is dx?
cirrhosis, due to fibrosis and regnerataive parenchymal nodules
some grain in china lead to p53 mutation, which cancer how?
aflatoxin made by aspergillus, infects grain, tgt with hep B is predisoposing to HCC
nocturnal cough, basal zone hyperplaisa, eos, lamina propira papillae elongatino, gets better with pantoprazole, dx?
GERD, relaxation and incompetence of GEJ
profuse watery diarrhea in HIV patient, mucosal biopsy shows inflammatory infiltrate in lamina propria and pathogens lining the epithelium, dx and usual location
cryptosporidium parvum, usually in small intestine
1 week ago had cholecystectomy in mexico, comes back with jaundice and fever and mild hypotension, dies two days later- liver biopsy shown, what is dx and mechanism? and what will be associated sign?
PT decrease. fulminant hepatitis due to inhaled halothane (used anesthetic worldwide), leading to acute liver injury. Other things like albumin and palmar erythema are late signs for CLD, but for acute liver injury, factor VII has shortest halflife
hematemesis, ulcer at the posterior wall of the duodenal bulb, which artery does it affect?
gastroduodenal from the common hepatic from celiac trunk. anterior wall of duodenum would lead to perforation
adenoma to carcinoma sequence regulated by what?
normal to early adenoma is APC/b-catenin, early adenoma to late adenoma is KRAS gene, late adenoma to carcinoma is TP53
what enzyme is involved in making pigment stones?, where is it produced?
beta-glucuronidase. produced by injured hepatocytes or from bacteria (c. sinensis) is common in East Asia), rmb glucoronides is what is conjugated to bilirubin. so cleaving this makes in unconjugated bilirubin, which is more susceptible to pigment stone formation
how does HBV allow for HDV infection?
HbSAg covers the HDV particles so it can infect hepatocytes
what two things cause sphincter of oddi contraction?
alcohol and mu opioid analgesics
strongyloides unique part?
not anal pruritis (for pinworm-vermicularis), but filariform (infectious larvae) and rhabdidiform (baby) larvae
why do pregnant people get gastric reflux?
decreased LES tone, due to estrogen and progesterone. and also increased gastric pressure later on in pregnancy
which microorganisms need the least amt to infect?
shigella, campylobacter, giardia, entamoeba
mice with mutation on leptin receptor, what is leptin levels and bmi of the mice?
high high because leptin produced by adipocytes to decrease appetite (POMC in arcuate nucleus and decreased NPY)
what is lacking from breastmilk? (3)
Vit K, Vit D, Iron (but has higher bioavailablity, so effective until 4 mo)
beta galactosidase and permease are synchronously produced by bacteria, in response to lactose. What is this called? and why does this happen?
polycistronic genes in prokaryotes (bacteria). due to there being multiple proteins translated from one mRNA transcript, using the lac operon- lactose inhibits the repressor from binding to the operator
hit by car on left side, shoulder pain, rigid and tender abdomen, hiccups and nausea, dx and why?
splenic laceration, due to phrenic nerve irritation and kehr’s sign
ischemic colitis, where does the infarction happen during hypotension
splenic flexure and rectosigmoid junction
what is mechanism of hepatic encephalopathy and what is it not?
BUN is the wrong answer because liver normally converts ammonia to urea but in cirrhosis cannot. increased nitrogenous substance (protein) absorption from GI tract (due to GI bleed, chinese wedding feast) liver can’t process, increase ammonia in circulation which causes neurotransmitter dysfunction.
crohn’s disease patient with loin to groin pain, why got kidney stones?
crohn’s–> affects terminal ileum, decreased absoroption of bile acids, decreased fat absorption, calcium that normally reacts with oxalate reacts with fat (saponificiation) causing increased oxalate absorption
hereditary hemochromatosis mechanism?
increased absorption of iron in enterocytes. HFE gene mutation is auto recessive, causing 2 things- hepcidin synthesis decreases, so increased ferroportin transporter activity. And also increased DMT1 to absorb iron from lumen
distal duodenal ulcer, taking a pain killer for OA of knee, gastrin concentration rises after secretin adminstration, dx?
zollinger ellison- gastrinoma secreting gastrin, usually distal, usually refractory to secretin, a/w MEN 1
diarrhea in AIDS patient, what two possibilities and distinguishing features?
cryptosporidium- in small intestine, non-ulcerating, partially acid fast, spores attached along epithelium. CMV colitis- in colon, ulcerating, large ovoid cells with basophilic intranuclear and intracytoplasmic inclusions
HIV meds make immature non-infectious virions. what is MOA?
protease inhibitor, usually cleaves gag-pol polyproteins but protease inhibitor renders these two ineffective and immature
dysphagia, smoker, keratinization, intracellular bridges, abundant eosinophilic cytoplasm, dx?
squamous cell CA
colonoscopy shows outpouchings, what is histological finding and dx?
absence of muscularis propria, diverticulosis
ulcerative colitis patient, with abdo pain, blood diarrhea, distension, dry mucous membranes, no rebound or guarding. dx and next step for dx?
toxic megacolon, plain abdo xray not colonoscopy or enema because can perforate!!!
two types of chronic gastritis and difference and complications!
autoimmune and hpylori. autoimmune is diffuse involvement and no ulcers but perncious anemia and adenocarcinoma, increased gastrin. hyplori is antrum/patchy, ulcers, and MALT lymphoma, and adenoCA
CF patient, recurrent infections, decreased proprioceptions and hyporeflexia and mild hemolytic anemia- what causes these symptoms?
Vitamin E deficiency. Fat soluble vitamins often deficient in CF, and vit E is the antioxidant vitamin. so neurons (long axons) and erythrocytes (high oxygen exposure) have high vulnerability to oxidative damage
one word on function/deficiency: niacin, thiamine, riboflavin, Vit C, Vit D, Vit E, Vit K, Vit A
B3 (ETC. pellagra-dermatitis,diarrhea,dementia). B1 (neurological, alcoholics, beri beri), B2 (FAD, anemia and neuropathy), Vit C (scurvy for deficiency, overuse-diarrhea, abdo pain nausea). Vit D (bone) Vit E (antiox) Vit K (27910) Vit A (nightblindness, corneal softening, dry eyes)
where do anal fissures occur and why
posterior midline due to poor blood supply
organs in order of likelihood to infarct and why is the last one the last one and what is exception?
brain, heart, kidney, spleen, liver. liver has dual blood supply and collaterals can form (but are absent in transplanted liver)
young chap with unprotected sex having fatigue, malaise, abdo discomfort, no raw food recently. what hepatitis?
Hep B, more likely sexual transmission. also blood stuff. Hep C is usually asymptomatic, and more blood than sex. Hep D also blood (co-or super infection with He[ B) Hep A is uncooked food, or endemic area
drugs given for hepatic encephalopathy (2) and mechanism of action
lactulose- catabolized into SCFA by gut bacteria, drawing fluids out into lumen as well as lowering colonic pH and converting ammonia to ammonium (NH4). Rifaximin -alters GI flora to reduce production of ammonia from nitrogenous stuff
CA-CRC (colitis associated colorectal CA) vs sporadic differences (in mutations as well)
early p53 mutation and late APC (opposite of sporadic) and high grade, poorly differentiated, flat lesions, synchronous, aggressive
5 receptors involved in vomiting (give examples) and 2 that are not (examples?)
5-HT3- ondansetron, D2 (dopamine)- metoclopramide, H1- diphenhydramine, M1 (muscarinic)- scopolamine, Neurkinin-1 (aprepitant- substance P inhibitor), NOT is mu opioid (morphine) and motilin (erythromycin given for gastroparesis)
c diff. Rx? and mechanism?
fidaxomycin- bacteriocidal that inhibits sigma subunit of RNA polymerase, oral macrocylic. Vancomycin- cell wall inhibitor. metronidazole- affect DNA in anaerobic. (given intravenously for severe- UTD)
mechanism of breastfeeding and breast milk jaundice
lack of breastfeeding–> no bowel mvmts–> increased enterohepatic circulation. breast milk has glucoronidase–> deconjugates bilirubin, –>increased enterohepatic circulation
patient with gastroenteritis before now presenting with bloating, flatulence, abdo pain, waterry diarrhea, milk related. what is related finding in this patient?
decreased stool pH- undigested lactose is fermented to produce short chain fatty acids that decrease pH and produce hydrogen gas as well, and also increase stool osmolality
young guy with weight loss and diarrhea and abdo discomfort. what is first test?====================================
sudan III stain of feces for fat malabsorption (most commonly implicated in malabsorption in general)
signs of RHF, and liver biopsy? what does it show
nutmeg liver, centrilobular necrosis (because zone 3 is closest to congested veins)
how is HCV treated and what mechanism?
DAA (direct antiviral agents) prevent viral lifecycle by inhibting replication and assembly
preveious giardia baby (2 years) comes back for recurrent diarrhea, frothy etc, dx?
lactose intolerance after infection
recent renal transplant, has burning chest pain with odynophagia and dysphagia and shallow linear ulceration in lower esophagus, with what is organism and histo findings?
CMV esophagitis- enlarged cells with intranuclear inclusions
how does alcohol causes liver damage?
NADH production as side effect of alcohol, prevents free fatty acid oxidation, and decreased apolipoprotein synthesis
young woman with early satiety and vomiting and gastric issues, with history of T1DM for 15 years on insulin, what is dx and mechanism?
diabetic gastroparesis, chronic hyperglycemia damages the enteric neurons such as NO containing neurons and interstitial cells of cajal which coordinate peristalsis and smooth muscle contraction
18 yo kid with recurrent childhood infections of respi system comes with cough fever hypoxemia and dies, autopsy finds absent vas deferens, gram neg rod infection. dx and associated finding on autopsy?
CF, infection with pseudomonas or burkholderia, and pancreatic duct distension and obstruction leading to pancreatic insufficiency
stomach cancer impinging on splenic artery, what artery is additionally affected?
short gastric
3 different mecahnism of vomiting
GI (infection, distension, chemo), neuro (migranous nausea), vestibular (motion sickness, peripheral vertigo)
copper lifecycle
absorbed, bound to albumin, taken to liver, made into ceruoplasmin, then broken down taken to liver, bile and then excreted in feces
which sugar is metabolized the quickest using the glycolysis pathway?
fructose because it bypasses PFK-1 (rate limiting enzyme)
night blindness and pruritis in middle age woman- dx?
vit A def secondary to biliary obstruction
patient with biiary colic due to cholesterol stone that is not obstructing. how to treat medically?
bile acid supplementation to increase solubility of cholesterol (ursodeoxycholic acid)
varices in the fundus only, esophageus is clear. where is the portal hypertension?
splenic vein
external hemorrhoids and internal hemorrhoids innervation?
pudendal and inferior hypogastric plexus
baby vomiting after breastfeeding, hepatomegaly, lethargy, jaundice, e-coli sepsis
galactosemia due to galactose-1-phosphate uridyl transferase deficiency (GALT)
which inflammation process underlies the formation of non-caseating granulomas?
Th1, activating macrophages
