GI Review Flashcards
Compare gastroschisis and omphalocele
Gastroschisis: defect in abdominal wall, guts protrude without a covering.
Omphalocele: persistent herniation of guts through umbilical cord; guts protrude COVERED by peritoneum
What are two functions of stellate cells in the liver?
Stellate cells store vitamin A and secrete collagen (for fibrosis) when activated
What hormone induces Migrating Motor Complexes?
Motilin
What signaling molecule is decreased in achalasia?
Nitric Oxide (normally relaxes LES)
What does VIP do?
Causes relaxation of smooth muscle and sphincters. Causes increased water and electrolyte secretion.
Ashton Kutcher and Denzel Washington are real VIPs (achlorhydria, hypokalemia, diarrhea that’s watery in VIPoma)
Compare indirect and direct bilirubin
Indirect bilirubin is insoluble in water (unconjugated form).
Direct bilirubin is conjugated form.
Name three salivary tumors. Which is malignant?
Warthrin and Pleomorphic adenoma are benign. Mucoepidermoid is malignant
Compare intestinal and diffuse gastric cancer
Intestinal: Discrete mass. Increased risk with H pylori, smoking, toxins, etc.
Diffuse: no discrete mass, signet ring cells. Not associated with H pylori
How does food affect gastric and duodenal ulcers
Gastric: Greater pain with food (acid secretion)
Duodenal: Decreased pain with food (bicarb secretion)
What antibodies can be detected in Celiac? Which can be used in IgA deficiency?
Anti-tTG. anti-endomysial. Anti-deaminated gliadin peptide (anti-DGP has IgG form!)
Features of Whipple’s Disease (6)
Foamy macrophages, Tropheryma whipplei (g+), Diarrhea, Cardiac sx, Arthralgia, Neurologic Sx
What type of helper T cell is involved in crohn’s and UC?
Crohn’s: Th1 (angrier macrophages -> transmural infl)
UC: Th2
Compare pathogenesis of appendicitis in kids and adults
Kids: lymphoid hyperplasia
Adults: fecolith obstruction
Hirschsprung disease is associated with ___ mutation and failure of ______________ (developmental step).
Hirschsprung disease is associated with RET mutation and failure of neural crest migration.
Sessile serrated polyps are associated with what genetic changes (2)?
CpG hypermethylation and BRAF mutations
What are extra-GI manifestations of FAP?
Soft tissue tumors, hypertrophy of retina, impacted teeth, medulloblastoma (Many Traumatic Rectal Screenings)
What part of the colon is most involved in Lynch syndrome?
proximal (R colon)
What marker is used to monitor CRC recurrence?
CEA (carcinoembryonic antigen)
Diagnosis of spontaneous bacterial peritonitis
More than 250 neutrophils in ascites fluid
Where do you find Mallory bodies? What are they?
Alcoholic hepatitis. Mallory bodies are cytoplasmic inclusions of keratin.
What serum marker can be used to follow hepatocellular carcinoma?
alpha-fetoprotein
Pathogenesis of alpha-antitrypsin (2)
Misfolded protein builds up in hepatocyte ER, causing cirrhosis. Lack of antitrypsin in lungs allows elastase to destroy alveoli, causing emphysema.
What syndrome has completely absent UDP glucuronosyltransferase? What is elevated?
Criggler-Najjar syndrome (critter in a jar). Elevated UNCONJUGATED bilirubin
What is Gilbert syndrome?
Benign version of Crigler-Najjar (still have UDP, but it’s less active). Only get jaundice with stress.
Describe Dubin-Johnson syndrome
Jaundice and black liver due to decreased excretion of conjugated bilirubin.
Describe Rotor syndrome
Same as Dubin-Johnson, except no black liver.
Where does bilirubin like to deposit in a neonate’s brain?
Basal ganglia
What is the timing of physiologic neonatal jaundice?
Occurs after first 24 hrs and resolved by 1-2 weeks
How does excess Cu and Fe cause damage?
These metals react with hydrogen peroxide to generate free radicals
What is the demographic and lab abnormality seen in Primary Biliary Cholangitis?
Seen in women (B=breasts). Anti-mitochondrial Ab present (mitochondrial DNA is female derived)
PBC v PSC. Which affects small v large bile ducts?
PSC affects extrahepatic (large) bile ducts (that’s why beaded string appearance is visible).
PBC affects lobular (small) bile ducts
Describe the pain of acute pancreatitis
Epigastric pain radiating to the back
How can acute pancreatitis cause hypocalcemia?
Pancreatic enzymes can leak out to surrounding fat. Fat necrosis causes precipitation of calcium soaps, sequestering calcium.
What differentiates a pancreatic pseudocyst from a true cyst?
Pseudocyst does not have epithelium lining.
Compare lipase findings in acute and chronic pancreatitis
Lipase is always elevated in acute pancreatitis. Lipase may not be elevated in chronic pancreatitis because there may be so little functional pancreas left that minimal lipase is actually produced.
What is migratory thrombophlebitis?
Redness and tenderness on extremities due to migrating peripheral clots. Associated with pancreatic cancer.
What serum markers are associated with hepatocellular carcinoma, pancreatic cancer, and colorectal cancer?
HCC = alpha fetoprotein (ascites looks like pregnant).
Pancreatic cancer = CA19-9 (99 problems and you hope pancreatic cancer ain’t one).
Colorectal cancer = CEA
Name 2 serrated colon polyps. Malignant potential?
Sessile serrated adenoma (malignant) and hyperplastic (benign) are both serrated
Do all adenomas have dysplasia? What are two types of adenoma?
YES. Adenomas are dysplastic by definition. Types are villous and tubular.
Which hepatocytes are most affected by acetominophen toxicity?
Hepatocytes around the central vein (centrolobular) b/c toxin is due to hepatic metabolite, not drug itself
Compare the effect of PNS and SNS on salivary secretion
PNS causes more acinar secretion AND vasodilation, leading to fluid-rich secretions.
SNS causes more acinar secretion only, leading to fluid-poor solutions.
Describe the effect of slow flow on salivary ductal cells.
Slow flow: secrete more KHCO3, reabsborb more NaCl
What is the effect of Substance P, VIP, and ATP on GI smooth muscle?
Substance P causes contraction. VIP and ATP cause relaxation.
What two metals compete for absorption in enterocytes?
Mg and Ca
PPIs are more effective than H2 blockers overall. What can H2 blockers do better?
H2 blockers are more effective at suppressing nocturnal acid and have more rapid onset.
GERD and PUD tx
GERD: start with H2 blocker, then move to PPI if needed
PUD: PPI
Should sucralfate be given on empty or full stomach?
Empty
What is the major contraindication of misoprostol?
Pregnancy (it induces abortion)
Ca, Mg, and Al compounds can all be used to neutralize stomach acid. What is the major side effect?
Calcium and Aluminum cause constipation. Mg causes diarrhea
Do all H2 blockers inhibit CYP450?
No. Only cimetidine
What is tegaserod and what is the major side effect?
Tegaserod treats constipation due to IBS. Risk of cardiac problems
How do you treat pregnancy-associated nausea?
- pyridoxine
- doxylamine (H1 blocker)
- diphenhydramine or meclizine
What drug is first line for constipation?
Psyllium (bulk laxative)
What is bisacodyl? Describe side effects and chronic use.
Irritant laxative. ADR: electrolyte deficiencies. Can be abused, but can also be used chronically safely (if in normal dose)
What is castor oil?
stimulant laxative (irritant)
What is the function of docusate?
used to prevent constipation
What does the stage of hepatitis represent?
The amount of scarring
What hepatic tumor has a female predominance?
Hepatocellular adenoma
Describe the serum findings of autoimmune hepatitis
Anti-smooth muscle IgG
What is the cut-off in the stool osmotic gap for osmotic diarrhea?
Osmotic diarrhea has a gap greater than 50
Why is there elevated folate in SIBO?
Bacteria make folate
Which gastric carcinoma has signet cells?
Diffuse gastric carcinoma
