GI Flashcards
What is the most common tracheoesophageal abnormality?
Esophageal atresia with distal tracheoesophageal fistula
Duodenal atresia is often associated with what syndrome?
Down
Duodenal atresia usually occurs distal to what structure? What does this cause?
Distal to the sphincter of Oddi, thus vomit is usually bilious
Nonbilious projectile vomiting = ?
Pyloric stenosis
weirdly giving macrolides is a risk factor for this.
Although the spleen is the weird foregut organ weirdly made from _____, it still has normal foregut blood supply, i.e. the _____ artery.
Mesoderm
Celiac
Despite the fact that the majority of the pancreas is formed from the _____ pancreas, the main outflow tract is from the _____ pancreas.
Dorsal
Ventral
Ventral duct drains to/is the common pancreatic duct
Dorsal duct = accessory pancreatic duct
What are esophageal findings/infections in HIV patients?
- Candida - grey white pseudomembranes on erythematous mucosa
- HSV-1 - small vesicles and punched out ulcers, intranuclear inclusions (Cowdry Type A)
- CMV - linear ulcerations, intranuclear and cytoplasmic inclusions
When performing an appendectomy, what anatomical finding can help you locate it?
Tenia coli - 3 distinct longitudinal bands that travel on the outside of the colon before converging at the root of the vermiform appendix.
What is/what causes an annular pancreas?
The ventral pancreatic bud normally rotates around the duodenum to fuse with dorsal pancreatic bud forming the uncinate process and main pancreatic duct (of Wirsung). Malrotation can cause duodenal obstruction or reduced pancreatic damage. Often is completely asymptomatic though.
How can cholesterol gallstones be treated medically?
Administration of hydrophilic bile acids which serves to reduce cholesterol secretion and increase biliary bile acid concentration, improving cholesterol solubility and promoting gallstone dissolution.
What is the pathogenesis of chronic alcoholic pancreatitis?
Alcohol causes increased proteinacious secretions that can precipitate forming ductal plugs that may calcify (and thus are detectable on abdominal imaging).
Ductal obstruction then causes exocrine insufficiency due atrophy of the pancreatic acinar cells and fibrosis -> malabsorption, diarrhea/steatorrhea, weight loss, frothy stools.
How many calories per gram in proteins/carbs/fat/etoh?
proteins/carbs 4 calories per gm
fat 9 cal per gm
etoh 7 cal per gm
Diverticulosis most commonly affects the _____ colon.
Sigmoid
What is the pathogenesis of diverticulosis?
Pulsion i.e. increased intraluminal pressure forcing herniation through areas of focal muscularis weakness of mucosa and submucosa (i.e. “false” diverticula!)
What is the “adenoma to carcinoma sequence”?
Premalignant dysplastic cells or small adenoma form as a result of APC tumor suppression genes -> KRAS mutation -> large adenoma -> TP53 mutation -> carcinoma
Increased activity of which enzyme has been found in many forms of colon adenocarcinomas?
COX-2
Regular administration of aspirin has been associated with lower rates of colonic adenomas and adenocarcinomas.
What is primary biliary cirrhosis (PBC)? What is the common patient-type? What are presenting symptoms?
A chronic autoimmune liver disease characterized by a dense portal tract infiltrate of macrophages, lymphocytes, plasma cells, and eos that results in granulomatous destruction of intrahepatic interlobular bile ducts “florid duct lesion”
Insidious presentation in middle-aged women:
Fatigue
Pruritus
Cholestasis (jaundice, pale stool, dark urine)
Hepatosplenomegaly
Xanthelasma/hypercholesterolemia
Can lead to cirrhosis and portal HTN in late stages
More than 90% of cases of acute cholecystitis are caused by gallstone obstruction of the _____ duct.
Cystic
An _____ does not extend beyond the mucosa while an _____ can go as far as the serosa/adventitia.
Erosion = mucosa only Ulcer = more extensive to serosa/adventitia
What features on histology can help you distinguish duodenum vs jejunum vs ileum
duodenum = Brunner's glands only jejunum = plicae circularis ileum = Peyer's patches
Foregut = Pharynx -> ?
Proximal duodenum
Midgut = Distal duodenum -> ?
Proximal 2/3 colon
Hindgut = ______ -> proximal rectum
Distal 1/3 colon
Which blood supply off the celiac trunk feeds esophagus (and thus is involved in bleeding in esophageal varices)?
Left gastric artery
Pancreatic cancer (adenocarcinoma) often causes a huge palpable gallbladder that is curiously ______.
Painless
Metoclopramide _______ resting GI tone
increases
Chagas disease, acquired in _______, can cause what esophageal problem?
S. America
Achalasia
What makes linitis plastica different than other gastric cancers?
NOT associated with h.pylori
Characterized by signet ring cells
Diffuse infiltration of stomach wall
H.pylori is slightly more associated with _____ ulcers, while NSAIDs are slightly more associated with _____ ulcers.
H.pylori -> duodenal
NSAIDs -> gastric
What is a stool Sudan Stain used to detect?
Fat malabsorption
HLA DQ2/8 + herpes herpetiformis = ?
Celiac
What is Whippel’s Disease and what characterizes it?
Caused by tropheryma whipplei (a bacteria) causes malabsoprtion and: foamy macrophages cardiac endocarditis arthralgia neuro sx
On histo: PAS+ granules in the lamina propria in addition to the foamy macrophages
Tropical sprue, which acts a lot like celiac (sprue), ultimately can lead to watch vitamin deficiencies?
B9 and B12 -> megaloblastic anemia
Although pancreatic insufficiency/chronic pancreatitis can cause B12 deficiency due to the acidification of the duodenum, what is the more common vitamin deficiency seen?
Fat malabsorption (A, E, D, K)
Crohn’s disease is marked by a Th__ response while Ulcerative Colitis is Th__.
Crohn’s Th1 + granulomas
UC Th2 + crypt abscesses
Ankylosing spondylitis, uveitis, erythema nodosum, and inflammatory polyarthritis is associated with what chronic GI disease?
IBD
What is first line treatment for UC and Crohn’s?
5-ASA drugs (Sulfasalazine or Mesalamine)
esp. useful in UC
In UC vs. Crohn’s which is more likely to cause frankly bloody diarrhea?
UC
Diverticulosis = painless Diverticulitis = painful
k
What part of the colon is most often affected in Hirschsprung’s disease?
Rectosigmoid
Major sign = no passage of meconium in the first 48 hours.
Red currant jelly stool = ?
Intussuseception
What are serrated colonic polyps associated with (mutations/pathways)?
BRAF mutations
CpG hypermethylation pathway
Microsatellite instability
What are adenomatous colonic polyps associated with (mutations/pathways)?
Cellular atypia
APC/KRAS mutations
Chromosomal instability
What marker is elevated in hepatocellular carcinoma?
AFP
Most common cause of hepatocellular carcinoma in the ABSENCE of cirrhosis?
Hep B
ArSenic (and vinyl chloride) causes what type of GI cancer?
Hepatic angiosarcoma
What is Budd-Chiari syndrome?
Obstruction of the venous outflow of the liver most commonly due to thrombosis/hypercoaguable state or myeloproliferative disorders
Alpha 1 antitrypsin deficiency = ___acinar emphysema, in contrast to smokers who get:
panacinar
while smokers get centriacinar
What are black gallstones?
Ca-bilirubinate
Occurs due to unconjugated bilirubin making its way into the gallbladder (i.e. can occur from hemolysis or cirrhosis)
What causes brown gallstones?
Bacterial metabolism
What type of gallstones occur in patients with Crohn’s?
Cholesterol
Black (Ca-bilirubinate)
What are the 2 major risk factors for pancreatic cancer?
smoking and age
this is still DESPITE the fact that gallstones, alcohol, and hypertriglyceridemia are what cause pancreatitis
Order of increasing cancer risk in polyps based on form/shape:
villous > tubulovillous > tubular
What is NF-kb?
A proinflammatory transcription factor that increases cytokine production.
In Crohn’s disease mutations in NOD2 result in a decreased activity of NF-kb which impairs the innate immune response of the intestinal mucosa.
____ levels of phosphatidyl choline precipitate cholesterol gallstones.
Low
Which hepatitis is characterized by an urticarial vasculitis and generalized joint pain and lymphadenopathy?
Hep B
Anemia and neruopathy: Vitamin ___ deficiency.
E
Spotty necrosis + “ballooning degeneration” (swelling and inflammation = ?
Acute hepatitis
How do you determine if an elevated Alk Phos is hepatic or bony origin?
Gamma-glutamyl transpeptidase (GGT)
Areas of chalky white fat depositions and calcification on the mesentery = ?
Acute pancreatitis
Diffusely enlarged pale cytoplasm with granular “ground glass deposits” = hepatitis ___
B
What are patients with porcelain gallbladders at higher risk for developing?
Adenocarcinoma of the gallbladder
Which chronic GI disease is marked by noncaseating granulomas on histology?
Crohn’s
Which type of ulcer gets WORSE with eating?
Gastric
Mallory-Weiss tears run _____ as the gastro esophageal junction.
Longitudinally
What are the receptor types associated with the different causes of n/v?
Vestibular (motion sickness/vertigo): H1 and M1 receptors in inner ear, CN VIII
Chemoreceptor trigger zone/migraine nausea (emetogenic substances): D2
GI tract mechanical and chemical irritants: 5-HT3, CN X from stomach CN IX from mouth/pharynx
What tests can be done to diagnose lactose deficiency?
Hydrogen breath test
Decreased stool pH due to increased short chain fatty acids like acetate that acidify the stool
Lymphatic channels proximate to the anal dentate line drain to which lymph nodes?
Inferior mesenteric and internal iliac
Lymphatic channels distal to the anal dentate line drain primarily tho which lymph nodes?
Inguinal nodes
Where in the stomach do most gastric ulcers form? What are the consequences for penetration at this site?
Along the lesser curvature of the stomach at the transitional zone between the gastric corpus and the antrum.
The left and right gastric arteries run along and perfuse the lesser curvature of the stomach and thus are common source of hemorrhage from penetrating ulcers.
Why does administration of total parenteral nutrition cause gallstones?
The absence of enteral passage of fat and amino acids into the duodenum eliminates the nature trigger for CCK release leading to contraction of the gallbladder -> biliary stasis.
What lifelong supplementation will patients who have had a total gastrectomy require?
B12 (water soluble) due to loss of intrinsic factor for normal absorption.
What are Councilman bodies?
Apoptotic hepatocytes from viral hepatitis that form round acidophilic bodies.
Which arteries are supplied by the splenic artery and thus are at risk in the event of splenic infarction?
Short gastric
Which vitamins do the bacteria involved in small intestine bacterial overgrowths (SIBO) generate that can then build up in the serum?
Vitamin K and folate
Ulcers found in the proximal duodenum suggest _____, while ulcers found distal to the duodenal bulb suggest ____.
Proximal = H pylori Distal = ZES (gastrinoma)
What effect does secretin have on parietal cells in ZES?
Paradoxically secretin INCREASES acid/gastrin production in ZES
Why does the liver turn black in Dubin-Johnson syndrome?
Impaired excretion of epinephrine metabolites -> accumulation within lysosomes
Also the basis of DJ is impaired excretion of bilirubin glucuronides.
Conjugated bilirubin = _____bilirubin
Direct
In cirrhotic patients, spider angiomas develop due to increased levels of what?
Estrogen
What is the flow of drainage of internal hemorrhoids?
superior rectal vein -> inferior mesenteric vein
What is the flow of drainage of external hemorrhoids?
inferior rectal vein -> internal pudendal vein -> internal iliac
What would cause an infant to appear healthy at birth but then appear with jaundice within the first 2 months of life?
Biliary atresia, a progressive complete or partial obstruction of extrahepatic bile ducts.
What kidney stones can form in Crohn’s? Why?
Calcium oxalate
Destroyed ileum prevents bile acid reabsorption leading to impaired fat absorption. Calcium which normally should bind to oxalate to promote its excretion instead binds to the excess lipid -> oxalate absorption increases promoting the formation of stones.
What is the mechanism by which a Crohn’s patient gets bowel obstruction?
Strictures due to fibrosis and hypertrophy of the muscularis mucosae, narrowing the intestinal lumen.
Biochemical mechanism of alcohol-induced hepatic steatosis:
Decreased fatty acid oxidation due to excess NADH from alcohol and acetaldehyde DH
80% of myxomas arise in the _______.
Left atrium
Most common primary cardiac neoplasm.
Histologically, look like scattered cells within a mucopolysaccharide stroma, abnormal blood vessels, and hemorrhaging.
Grossly they are pedunculated and gelatinous.
