Gastroenterology Flashcards
Why do you see fat accumulation in alcoholic hepatic steatosis?
Decreased fatty acid oxidation since alcohol provides NADH from metabolism by alcohol and aldehyde DH
What is the histology of carcinoid tumors?
Nests/sheets of cells with round/oval nuclei and eosinophilic cytoplasm; very uniform looking
Increased gastric acid causes an ulcer where?
Duodenum!!!
When do you get gastric ulcer?
When H. pylori destroys the epithelial lining of stomach from ammonia production
What looks like a velvety cauliflower mass?
Villous adenomas
What is a polyp symptom specific for villous adenoma?
Secretory diarrhea (due to large amounts of mucus production)
Person ingests 13C labeled urea and then breath out 13C labeled CO2. What does this mean?
They have an H. Pylori infection. It is urease positive so it breaks down urea and the CO2 crosses into the blood and breathed out.
Why do you get fistulas and strictures in Crohn’s?
Transmural inflammation
What does Boerhaave present with?
Pleural effusion, retrosternal chest pain, left pneumothorax
What does Mallory Weiss present with?
Hematemesis after vomiting lots
What does stomach adenocarcinoma present with?
Virchow node (enlarged left supraclavicular node)
What is the embryonic tissue origin of the spleen?
Mesodermal
What is the pertechnetate scan for?
Meckel’s diverticulum
What is Trousseau Syndrome?
Redness and palpable purpura on extremities (migratory thrombophlebitis)
In what setting do you see Trosseau syndrome?
Pancreatic adenocarcinoma
What is courvoisier sign?
Obstructive jaundice with palpable nontender gallbladder? Seen in pancreatic adenocarcinoma
What do exclusively beast fed infants require?
Vitamin D supplementation
What is the function of Niacin?
Inhibits VLDL synthesis and lipolysis
What acid-base thing do you see with vomiting?
Metabolic alkalosis
What would you get if on parenteral nutrition?
Gallstones due to lack of enteral stimulation secondary to decreased CCK
What is the pathology of PBC?
Granulomatous bile duct destruction and lymphocyte portal duct infiltrate
What does the pathology of PBC look similar to?
Graft vs Host Disease (GVHD)
Why do you get gallstones in Crohn’s?
Impaired bile acid absorption which causes impaired fatty acid absorption. Calcium binds to it forming soap complexes and gets excreted in feces.
Why do you get kidney stones in Crohn’s?
Less calcium in gut lumen to bind to oxalate since it is binding unabsorbed lipids instead
Which stomach artery is most susceptible to ischemia?
Short gastric because of lack of anastamoses
A jejunal ulcer is most likely due to what?
Gastrinoma
In what setting do you see mallory bodies?
Alcoholic Hepatitis
What are you at risk for if exposed to vinyl chloride and arsenic?
Liver angiosarcoma
Where is phosphatidylcholine found?
In bile acids
Which organ in the abdomen is least likely to get infarct?
Liver (due to dual blood supply; also has accessory supply from inferior phrenic, intercostals)
In what situation would you see a liver infarct?
Liver transplant since anastamoses are cut
What is a major effect of fibrates?
Decrease triglycerides
Posterior duodenal ulcers are most likely to cause bleeding from what?
Gastroduodenal artery
Anterior vs posterior duodenal ulcers are more prone to?
Anterior: perforation
Posterior: hemorrhage
Where is the duodenal bulb?
Right after the pylorus
How far to gastric erosions extend?
Into the muscularis externa but not all the way through (destroys gastric pits and glands)
Where are gastric pits?
In the mucosa
Where are gastric glands?
In the lamina propria
How far to gastric ulcers extend?
Submucosa
What causes acute mesenteric ischemia?
Atherosclerosis of mesenteric arteries (similar to angina)
What does acute mesenteric ischemia present with?
Epigastric post prandial pain
How do you differentiate acute mesenteric ischemia and peptic ulcer disease?
Peptic ulcer disease resolves w/ antacids and is not aw/ atherosclerosis
Cystic Fibrosis patient with acute pancreatitis is likely to be infected with what?
Pseudomonas
What does acute hepatitis present with?
Fever, nausea, anorexia, RUQ pain, bilirubinuria
What does acute hepatitis histology look like?
Ballooning, infiltrate, councilman bodies (eosinophilic globule in liver due to apoptosis)
Can conjugated bilirubin be excreted into the urine?
Yes because it is water soluble and doesn’t need to bind to albumin
What would yo see on a radionuclide biliary scan during cholecystitis?
Nothing (failed visualization)
What do you see in the liver for sarcoidosis?
Scattered granulomas with Schauman and Asteroid bodies
What is a common complication of UC and how do you diagnose it?
Toxic megacolon. Diagnose by X-ray (colonoscopy and barium enema are contraindicated)
What causes autodigestion of pancreas?
Trypsin
How do right sided colon cancers present?
Fatigue, weight loss, iron deficiency anemia from bleeding
What is acalculous cholecystitis?
Inflammation of gallbladder without presence of stones. From ischemia
What is ectopy?
Structure/organ not in its usual place (Ex: Meckel’s Diverticulum)
What enzyme is colonic adenocarcinoma linked to and what can you use to block it?
COX2 (use aspirin)
Where do anal tears occur?
Distal midline posterior to dentate line
Where do you see dermatitis herpetiformis?
On the butt’s and extensor surfaces of adults?
Where do you see eczema (atopic dermatitis)
Rash on trunk aw/ food (differentiate from dermatitis herpetiformis which is on butt and extensor surfaces)
How does PBC commonly present?
Caucasian female with history of extreme pruritus now getting xanthelesma and pale stool
How is copper normally excreted?
In bile (absorbed in the GI tract then carried by albumin to liver then bound to ceruplasmin and excreted through bile)
What does alpha amanitin do?
It is from mushrooms and it inhibits RNA Pol II preventing mRNA synthesis. Toxic to hepatocytes, GI tract, PCT cells.
What causes mallory weiss tears?
Increased intraabdominal pressure that causes retching?
What causes esophagitis in HIV patients?
CMV, HSV, candida
If you undergo gastric resection, what specific nutrient do you need?
Vitamin B12
How do you diagnose Hirschsprung’s Disease?
Sample the submucosa of the narrowed part
Lynch/HNPCC and sporadic colon adenocarcinoma are where?
Lynch/HNPCC: right
Sporadic: left
What is a major toxicity of Omeprazole?
Hip fracture from decreased Ca absorption
What is colitis associated carcinoma?
Progresses from fat and non-polypoid dysplasia; has mucinous nad signet rings; affects younger patients
What mutation is colitis associated carcinoma associated with?
Early: p53
Late: APC
Where do you see colitis associated carcinoma?
Proximal colon but can be multifocal
How do you diagnose malabsorption?
Stool test to look for fat
When do you see thin curvilinear lines of lucency (pneumatosis intestinalis)?
Necrotizing enterocolitis (bacterial invasion and ischemic necrosis o bowel wall see in premies and when enteral feeding began)
What is gallstone ileus?
Fistula between gallbladder and small intestine leading to gallstone passing through small intestine and getting stuck at ileocecal valve?
What causes air int he gallbladder and biliary tree?
Gallstone ileus (fistula between GB and SI)
How does HBV cause hepatocellular carcinoma?
HBV integration into host genome
What is acarbose/miglitol?
Glucosidase inhibitor that prevents hydrolysis of disaccharides into monosaccharides so they can’t be absorbed
Side effects of Acarbose/Miglitol
Flatulence, bloating
Ulcer in the distal duodenum is due to what?
Gastrinoma (Zollinger - Ellison)
What should you neonatal hepatitis make you suspicous for?
A1AT Deficiency
What does newborn with projectile nonbilious vomiting have?
Pyloric stenosis
What does newborn with projectile bilious vomiting have?
Volvulus
What happens if caudal fold fails to close?
Bladder exstrophy
What is an H-type TEF?
Pure TEF where there is a fistula alone
What does the splenorenal ligament contain?
Splenic artery and vein, tail of pancreas
Where are plicae circulares not located?
Duodenum
Where do peyers patches begin?
Ileum
Where does inferior epigastric come off?
External iliac
Where does superior epigastric come off?
Internal thoracic/mammary
What does the femoral sheath not contain?
Femoral nerve
Which hernia most likely to be incarcerated?
Femoral
Phenylalanine and tryptophan are potent stimulators of what?
Gastrin
What is a motilin receptor agonist?
Erythromycin
What does VIP do?
Increases intestinal water and electrolyte secretion, relaxes smooth muscle and sphincters
What neurotransmitter is used to stimulate G cells?
GRP
What test do you to distinguish GI mucosal damage from other causes of malabsorption?
D-Xylose test
What type of cancer does alcohol cause in the esophagus?
Squamous cell
What causes a cushing’s ulcer?
Increased vagal stimulation leading to increased acid production
What causes a curling ulcer?
Decreased plasma volume causing gastric sloughing
If gastric ulcer perforates what artery bleeds?
Left gastric
What does abetalipoproteinemia present with?
Night blindness, acanthocytes, ataxia, steatorrhea, FTT
When do you see air in the bladder?
When diverticula perforate and cause colovesical fistula
Where do zenker’s diverticulum occur?
At kilian triangle between thrypharyngeal and cricopharyngeal parts of inferior pharyngeal constrictor
What is angiodysplasia?
Tortuous dilation of vessels in cecum, terminal ileum, ascending colon, Can cause hematochezia
Why does aspirin cause reye’s?
Decreases beta oxidatoin by reversible inhibition of mitochondrial enzyme
Can you biopsy a cavernous hemangioma?
No because it has a risk of hemorrhaging
What is hepatic adenoma?
Benign liver tumor related to oral contraceptive or anabolic steroid use. May regress sponataneously or rupture
What can you use to treat crigler-najjar?
Phenobarbital (increases liver enzyme synthesis)
What do you see on histology for pancreatic adenocarcinoma?
Disorganized glandular structure with cellular infiltration
What are the risk factors for pancreatic adenocarcinoma?
Tobacco, DM, Age >50, Jewish, African-American males, chronic pancreatitis
What are the side effects of cimetidine?
CYP inhibitor, antiadrogenic effects (impotence, gynecomastia, prolactin release etc), can cross BBB (headaches, confusion)
What are the side effects of PPI?
Pneumonia, osteoporosis, decreased Mg, increase risk for c. diff
What does ApoE do?
Remnant uptake
What does ApoC do?
LPL cofactor
Peptic ulcer where is least associated with malignancy?
Duodenum (gastric ones can progress to adenocarcinoma or MALToma)
What happens with the HFE gene is mutated?
Decreased hepicidin synthesis (less iron taken up from blood) and increased DMT1 (more iron uptake from GI lumen)
What will decrease in lactose challenge in someone with lactase deficiency?
Stool pH (bacteria ferment lactose to make fatty acids)
What is the D-xylose test for?
To check for malabsorption
How do you test for lactase deficiency?
Lactose is given and then seen if patient’s blood glucose goes up and if they experience GI symptoms (bloating, diarrhea etc)
Gastric and pancreatic tissue in Meckel’s is a type of: dysplasia, metaplasia, ecotpy?
Ectopy (tissue present in unusual locations because of embryonic maldevo)
What is the problem with abetalipoproteinemia?
MTP gene mutation (MTP ensures proper ApoB folding) so can’t make chylomicrons, VLDL and absent cholesterol and triglycerides. Poor lipid absorption.
Diagnosis: weight loss, anorexia, jaundice, dark urine, pale stools, gallbladder enlarged but nontender?
Pancreatic adenocarcinoma. The gallbladder thing is Courvoisier’s sign. That and obstructive jaundice indicate pancreas cancer.
What does the ventral pancreatic bud make?
Part of the head, main pancreatic duct, uncinate process
What causes bilious vomiting, absence of large segment of bowel, distal ileum winding around vascular stalk?
Vascular occlusion leading to intestinal atresia distal duodenum. If SMA obstructed, apple peel atresia –> blind proximal jejunum with absence of long length of small bowel due to ischemia and terminal ileum winding around ileocolic vessel.
What would you see hyperpigmented mouth lips, hands + abdominal discomfort?
Peutz-Jeghers
What is metaclopramide?
D2 antagonist, inc resting tone/contractility
Contraindicated in parkinson and small bowel obstruction
Interacts with digoxin and diabetic agents
Drowsiness, fatigue, restlessness, depression, nausea, diarrhea
Where are the GI stem cells ?
Crypts of Lieberkuhn
What drug can you use for weight loss in obese people?
Orlistat
If mass in rectum that has metastases to liver and abdominal nodes, what was the venous route?
Inferior mesenteric vein (that drains into portal vein into liver explaining the liver metastases; also upper rectum drains into internal iliac nodes)
Inferior rectal vein would drain into systemic circulation and cause lung metastases
What is a truncated form of ApoB100 and where is it produced?
ApoB48 produced in intestinal cells
ApoB100 in hepatocytes
What looks like edematous friable and granular mucosa with neutrophils in crypt lumina?
UC
Crypt abscesses = neutrophils in crypt lumina
What does Kaposi show on endoscopy?
Hemorrhagic nodules
What do you suspect if bilateral pitting lower extremity edema without cause (ie CHF, cirrhosis etc)?
IVC obstruction (also see abdominal wall collateral venous circulation - aka epigastric veins)
What is caput medusa from?
Anastamoses between paraumbilical and small epigastric veins
Where does copper deposit in the eye in Wilson’s?
Descemet’s membrane of CORNEA
Which type is associated with H. pylori? Intestinal or diffuse?
Intestinal
