Week 3 Flashcards
MRI imaging for liver and gallbladder
- T2 weighted MRI is best for imaging …
- T1 Weighted MRI is best for imaging…
- MRCP is best for imaging… and can diagnose….
- darker liver parenchyma, brighter gallbladder / common bile duct
- brighter liver parenchyma, darker gallbladder / common bile duct
- visualization of biliary tree (NON-INVASIVE bc does not require IV contrast) → for diagnosing Choledocholithiasis (stones in bile ducts)
- What imaging technique is used for cirrhosis?
- ultrasound
- look at outline of liver- this shows cirrhosis
- What imaging technique is best used for cholelithiasis (gallstones)?
- ultrasound - stones leave dark shadows (white arrows)
second image …
- Black arrow show gallstones at gallbladder neck
- Blue arrow show thickened wall of gallbladder
- White dotted arrow show pericholecystic fluid
how do you differentiate focal nodular hyperplasia and hepatocellular carcinoma on CT imaging?
- Focal nodular hyperplasia (FNH) is a benign liver lesion that is composed of a proliferation of hyperplastic hepatocytes surrounding a central stellate scar.
- hepatocellular carcinoma does not have the stellate center
Pancreatitis on CT or MRI - what should you look out for in imaging
- peripancreatic fluid (asterisk - this is MRI image)
Necrotizing pancreatitis on CT - how do you know it is necrotizing pancreatitis?
- White tissue (white arrow on left image) - shows the leftover viable tissue, the tissue to left is necrotic
- What are pancreatic pseudocysts?
- How are they seen on imaging (CT)?
- well-circumscribed collections of homogenous fluid attenuation - most common complication of pancreatitis
How does chronic pancreatitis look different from acute pancreatitis in imaging?
- parenchymal fibrosis / fatty change / calcifications
How does pancreatic adenocarcinoma look like on imaging (ultrasound)?
- irregular margins of mass in pancreas (outlined by arrows)
Label what each image is
image
What does this image show in intestines?
toxic megacolon
Hepatitis A
- DNA/RNA?
- transmission?
- vaccine?
- RNA (non-enveloped, (+) ssRNA, linear, icosahedral)
- fecal-oral
- yes
Hepatitis B
- DNA/RNA?
- transmission?
- vaccine?
- DNA (enveloped, partially dsDNA, circular, icosahedral)
- body fluids
- yes
Hepatitis C
- DNA/RNA?
- transmission?
- vaccine?
- RNA (enveloped, (+) ssRNA, linear, icosahedral)
- body fluids
- NO
Hepatitis D
- DNA/RNA?
- transmission?
- vaccine?
- RNA (enveloped, (-) ssRNA, circular genome)
- body fluids
- NO
Hepatitis E
- DNA/RNA?
- transmission?
- vaccine?
- RNA (non-enveloped, (+) ssRNA, linear, icosahedral)
- fecal-oral
- Not in US
- What are some symptoms of viral hepatitis (infection of liver which leads to chronic liver inflammation)
- AST > or < ALT
- Bilirubin levels
- often asymptomatic or fever, GI symptoms, RUQ pain, jaundice, itching (due to bile salts in skin), dark urine, clay-colored stools (due to lack of of bilirubin excretion)
- ALT>AST - both are increased
- Increased bilirubin
Hepatitis A
- how is it diagnosed?
- is vaccine activated or inactivated?
- infection is chronic or self limited?
- anti-HAV IgM antibodies + symptoms OR anti-HAV IgG antibodies (IgM are first antibodies body makes to fight infections and IgG are antibodies that take a while to make so it indicates infection was not so recent)
- inactivated IM injection
- self limited
Hepatitis B
- Incubation period?
- what type of vaccine is available for this?
- Is this mostly self limited or chronic?
- extrahepatic manifestations? (2)
- long incubation period: 1-4 months
- recombinant HBsAg (to make anti-HBsAg antibodies w/o HBc or HBe antibodies)
- Can be either but chronic is common in infant children - and risk progression to cirrhosis, liver failure, hepatocellular carcinoma
- polyarteritis nodosa (a rare multi-system disorder characterized by widespread inflammation, weakening, and damage to small and medium-sized arteries) and glomerular disease
Hepatitis B
- What does HBsAg mean
- What does HBcAg mean
- What does HBeAg mean
- Hep B surface antigen (A protein on the surface of hepatitis B virus)
- Hep B core antigen (an inner core protein)
- Hep B e antigen (a secretory protein processed from the precore protein)
HBV antigens and antibodies help tell you the infection status of person.
- What do you find in a person that is immunized the HBV?
- IgG antibody - Anti-HBs (antibody against surface antigen of HBV)
HBV antigens and antibodies help tell you the infection status of person.
- What do you find in a person that has acute HBV infection? (3)
- HBsAG (HBV surface antigen)
- HBeAG (HBV e antigen - indicates significant viral replication/highly infectious)
- Anti-HBc (antibody against core antigen - IgM)
HBV antigens and antibodies help tell you the infection status of person.
- What do you find in a person that is in their window period (The time between exposure and when antibodies can be detected) of HBV infection? (1)
- What is undetectable? (2)
- When does this window period happen?
- anti-HBc (IgM) - antibody against core antigen)
- HbsAG (surface antigen) and anti-HBsAG (antibody against surface antigen)
- After HBsAG and HBeAG have peaked and fallen + after symptoms BUT before the peak of anti-HBs (plus presence of other two antibodies)
Out of the three antigens in HBV which ones are detectable in serum?
- only “e” and surface antigens. Core antigen is not found in serum.
HBV antigens and antibodies help tell you the infection status of person.
- What do you find in a person that is in chronic (high infectivity) portion of HBV infection? (3)
- HBsAG, HBeAG, and Anti-HBc (IgG)
HBV antigens and antibodies help tell you the infection status of person.
- What do you find in a person that is in chronic (low infectivity) portion of HBV infection? (3)
- HBsAG, anti-HBe, and Anti-HBc (IgG)
HBV antigens and antibodies help tell you the infection status of person.
- What do you find in a person that is in the recovery portion of HBV infection? (3)
- Anti-HBs, Anti-HBe, Anti-HBc (IgG)
HBV antigens and antibodies help tell you the infection status of person.
- What do you find in a person that is immunized to HBV? (2)
- Anti-HBs and Anti-HBc (IgG)
NRTI (nucleoside/tide reverse transcriptase inhibitors)
- For what hepatitis type is this used for?
- Name of drugs in this category?
- Mechanism of action? (how do the two drugs act differently?)
- chronic Hep B
- Entecavir and tenofovir
- Inhibition of reverse transcriptase to prevent virus production → Entecavir (guanosine analogue) and Tenofovir (adenosine analogue)
Interferon Alpha 2a/Alpha 2b
- For what hepatitis type is this used for?
- Mechanism of action?
- chronic hep B
- inhibits viral penetration and induces proliferation of macrophage and helper T cell for immune defense
Ribavirin
- For what hepatitis type is this used for?
- Mechanism of action?
- special instructions?
- side effects? (5)
- Chronic Hep C
- Inhibits replication of HCV but mechanism not clear
- monotherapy is ineffective. Needs to be combined with interferon or DAA (direct acting antiviral)
- hemolytic anemia, MI, depression, fatigue, rash
Direct Acting Antivirals (DAA)
- For what hepatitis type is this used for?
- Mechanism of action?
- Chronic Hep C
- direct inhibition of the function of HCV specific proteins
3.
What are the three different “products” within the category of Direct Acting Antivirals (DAA) → MOA, drug name, and suffix for (BLANK)
- (BLANK)
- NS5A inhibitor
- NS5B polymerase inhibitor
- NS3 /4A protease inhibitors
- -previr suffix (simeprevir)
- NS3/NS4A is responsible for cleaving and processing the HCV encoded polyprotein which is important for HCV viral life cycle
What are the three different “products” within the category of Direct Acting Antivirals (DAA) → MOA, drug name, and suffix for (BLANK)
- NS3 /NS4A protease inhibitors
- (BLANK)
- NS5B polymerase inhibitor
- NS5A inhibitor
- -asvir suffix (ledipasvir)
- NS5A is a viral phosphoprotein that has a role in replication, assembly, and release ← inhibiting this
What are the three different “products” within the category of Direct Acting Antivirals (DAA) → MOA, drug name, and suffix for (BLANK)
- NS3 /NS4A protease inhibitors
- NS5A inhibitor
- (BLANK)
- NS5B polymerase inhibitor
- End in suffix -buvir (sofosbuvir)
- NS5B polymerase - important for replication
used in combo with NS5A inhibitor
What are kupffer cells in the liver?
- fixed tissue macrophages within sinusoids (vascular channels that receive blood from terminal branches of the hepatic artery and portal vein at the periphery of lobules and deliver it into central veins)
- they phagocytose cell debris and old RBCs
- Endothelial cells of liver form a barrier between what two structures?
- What is the purpose of the endothelial cells creating a fenestrated barrier?
- sinusoids and space of disse
- allow passage of macromolecules w/out allowing blood cells through
Stellate (Ito) Cells – (HSC)
- What are they and what is their function?
- Where do they reside?
- What does it store?
- Complications from overactivation of these cells?
- They are quiescent fibroblasts are activated by inflammatory mediators to commence collagen synthesis. upon liver injury, stellate cells transform into fibroblast like cells and can do scar tissue generation → can make type I/III collagen + remodel ECM
- space of disse
- vitamin A (in large fat droplets within the cell)
- fibrosis/cirrhosis
- What is found within a portal triad in the liver?
- What does the central vein drain into?
- branch of hepatic artery
- branch of portal vein
- bile duct
- central vein drains into IVC
The organization of the liver can be described in 3 different formats. Describe what each format means
- Hepatic lobule
- Portal lobule
- Zones of Portal Acinus
- Hepatocytes drained by a single central vein and hepatocyte is surrounded by 6 portal triads (hexagon shape)
- three hepatocytes are drained by a single bile duct (makes a triangle between 3 central veins)
- There are three zones within the hepatocyte based on ATP levels and oxygenation of blood
Zones of Portal Acinus (based on ATP and oxygenation levels)
- Zone I - describe ATP and O2 levels + alternative name
- Zone II - describe ATP and O2 levels + alternative name
- Zone III - describe ATP and O2 levels + alternative name
- High ATP, High O2 — Periportal
- mid — transitional
- Low ATP, Low O2 — Pericentral (by central vein)
- What reactions are more likely to happen near periportal side (4)
- What reactions are more likely to happen near pericentral side
- Periportal - reactions that require ATP (such as gluconeogenesis, AA catabolism, urea cycle, albumin synthesis)
- Pericentral - don’t require much ATP (such as glycolysis, FA synthesis, Toxin metabolism)
- What zone is more susceptible to ischemia?
- Why?
- zone III
- Zone III is more susceptible to ischemia because it has less O2 concn
- What zone of liver is most affected by viral hepatitis?
- What zone is where alcoholic hepatitis occurs?
- What is the metabolite of ethanol that affects liver?
- What is the metabolite of acetaminophen that affects liver?
- Zone I
- Zone III
- acetaldehyde
- NAPQI
these to metabolites of toxins affect/injure liver
What is phase 1 reactions vs phase 2 reactions in metabolism of toxins in livers?
- phase 1 reactions - make primary metabolite under the P450 enzymes. Some toxins are able to be excreted in urine or bile after this first phase I reactions.
- Phase 2 reactions - when primary metabolite (that is still unable to be excreted) undergoes another reaction to make secondary metabolite to make it ionized and able to be excreted via urine or bile
- What vitamins are stored by liver?
- What vitamins are activated in liver?
- What is the liver’s interaction with copper?
- Vitamin A and Vitamin B12
- Vitamin D activation (D3 → 24 ‘-OH)
- allows for copper metabolism. Exports copper into blood via attachment to ceruloplasmin → then it can be excreted into stool via bile
What proteins are formed in the liver? (4)
- albumin (hypoalbuminemia happens in advanced cirrhosis for this reason)
- lipoproteins
- prothrombin (increased PT is seen in liver dysfunction for this reason)
- transferrin
How does liver help in excretion of bilirubin?
- conjugation of bilirubin occurs in hepatocytes which allows for proper excretion. Once conjugated it can be actively transported into bile canaliculi by MRP2 transporter
- Hemolytic Jaundice - excessive RBC breakdown → leads to increase in [unconjugated/conjugated] bilirubin
- Hepatocellular jaundice - liver injury → leads to increase in [unconjugated/conjugated] bilirubin
- Obstructive Jaundice - obstruction in bile or pancreatic ducts → leads to increase in [unconjugated/conjugated] bilirubin
- unconjugated
- both
- conjugated
- Where is bile made?
- liver
- Where are bile canaliculi?
- In what direction does bile move in relation to periportal and pericentral
- Bile canaliculi also known as bile capillaries are thin tubes that receive bile secreted by hepatocytes. The bile passes through canaliculi to the hepatic bile ducts and then into the common hepatic duct which drains directly into the duodenum.
- from pericentral to periportal
- Why do hepatocytes have a frothy appearance?
- are nuclei small or large?
- because of the glycogen content
- large nuclei
In portal triad you have hepatic arteriole, portal venule, and bile ductule
- What is the oxygenation levels of blood coming in through hepatic arteriole and portal venule
- Hepatic arteriole is fully oxygenated (comes from caval system)
- Portal venule is partially oxygenated (comes from portal system)
Gallbladder
- What is the purpose of gallbladder in terms of bile?
- epithelial cells absorb ions, extracts water → this leads to bile becoming 10X more concentrated
Gallbladder
- What cells are found in mucosa? What is the histological marker of gallbladder?
- special structures of submucosa and muscularis mucosa
- is gallbladder is covered by adventitia or serosa
- very tall simple columnar epithelial cells - highly folded mucosa (appearance of bridges)
- there is no submucosa or muscularis mucosa
- majority is covered with serosa but liver attachment is covered with adventitia