Limjoco- Liver Path X 10 Melissa Flashcards
The liver connects blood flow between which two entities?
Describe the blood supply to the liver.
- GI system and systemic circulation
- Liver has DUAL blood supply
(2/3 = portal vein; 1/3= hepatic artery)
What is the portal triad?
- Hepatic artery
- Portal vein
- Common bile duct
Describe blood flow through the liver; where does the portal venous blood mix with blood from the hepatic artery?
Describe the composition of portal venous blood and blood in the hepatic artery…
Portal venous blood + Hepatic arterial blood mix in sinusoids–> Central vv’s –> Hepatic vv’s –> IVC–> R. Atrium
- *Portal venous blood has LOW O2 and ^ nutrients from GI system
- *Hepatic Arterial blood has ^ O2 and comes from the heart
What are kuppfer cells?
Specialized MQs found in liver sinusoids
What do we call the space between endothelial cells and hepatocytes in the liver? What are the cells within this space called? What do they do?
Space of Disse: contains STELLATE (Ito) CELLS that mediate such pathological events like liver fibrosis (liver stem cells)
Describe the shape of a liver lobule? An acinus?
How does blood supply change throughout the acinus?
A lobule is the area surrounding a central vein; lobules have lowest O2 content in the center (near the vein)
An acinus is the space between a branch of the hepatic artery and the center of a lobule (hepatic vein); O2 content DECREASES with increasing distance from the hepatic artery (approaching the center of a lobule)
The liver metabolizes… (3)
carbs, lipids and fats
The liver synthesizes … (5)
- albumin
- clotting factors: I, II, V, VII, XIII
- Lipoproteins (VLDL, LDL, HDL)
- cholesterol
- glycogen
The liver catabolizes… (3)
- ammonia–> urea (urea cycle***)
- hormones
- drugs/ chemicals
The liver stores… (4)
- glycogen
- TGs
- Fe, Cu
- Vit ADEK
The liver excretes… (2)
bile and endogenous waste
Describe the liver’s role as blood reservoir; under what type of stimulus will the amount of stored blood increase?
Sympathetic stimulation INCREASES the amount of blood stored in the liver
How does the liver play a role in endocrine function?
- synthesis of vitamin D
- removal of circulating hormones i.e. glucagon, etc.
What are the two serum transaminases and how are they indicative of liver function? What is their normal role in liver function
- Aspartate amino transferase (AST)
- Alanine amino transferase (ALT)
AST and ALT will INCREASE in serum in response to hepatocyte injury; normally facilitate amino acid metabolism
What is the function of alkaline phosphatase?
Elevated ALP in serum indicates what kind of disease?
- ALP removes PO4 groups (bile duct cells + liver cells)
- Elevated in CHOLESTATIC disease
Gamma Glutamyl Transpeptidase: what is the function of this enzyme? What does elevated GGT in serum indicate?
- GGT is involved in glutathione metabolism + drug detox
- ^ GGT + ^ ALT in serum indicated HEPATOBILIARY DISASE
What is the most sensitive indicator for liver disease?
^^^ serum GGT
What does albumin do? How is serum albumin content changed in liver disease?
- Albumin maintains normal oncotic pressure
- LOW serum albumin is indicative of liver disease (degree depletion NOT indicative of disease severity)
What is the #1 cause of acute hepatitis?
viral hepatitis
List some potential causes of acute hepatitis?
Do not memorise list; each will be discussed independently; just for overview
- viral hepatitis
- acetaminophen toxicity
- idiosyncratic drug response
- ETOH
- Autoimmune hepatitis
- metabolic disorders (Reye, acute fatty liver of preggos)
- circulatory disorders (Budd- chiari, right heart failure)
Describe spotty/ lytic necrosis; with what disease state is it associated?
Acute Hepatitis
- clusters of small lymphs surrounding liver cells
Describe ballooning degeneration; with what disease state is it associated?
Acute Hepatitis
- fluid filed hepatocytes
Describe interface hepatitis; with what disease state is it associated?
Acute Hepatitis
- lymphocytic infiltrate surrounds portal tract and spills over limiting plate into lobule
Describe confluent necrosis; with what disease state is it associated?
Acute hepatitis
- many dead cells with pale cytoplasm
- possible ‘functional islands’ of spared tissue
Describe bridging necrosis with what disease state is it associated?
Acute Hepatitis
- ^^^ fibroblasts
- spans 2 architectural structures (i.e. portal vein and hepatic artery, etc.)
Three possible clinical outcomes of acute hepatitis?
How does confluent necrosis or chronic injury influence the liver’s regenerative capacity?
- spontaneous resolution with supportive tx.
- acute liver failure
- chronic hepatitis
**regeneration of hepatocytes will continue in spite of chronic injury or confluent necrosis
What are 6 clinical manifestations of acute hepatitis?
- encephalopathy (acute)
- coagulopathy –> GI bleeds
- acute renal failure (pre renal)
- infection, sepsis
- respiratory failure
- CV collapse
What is Acute Hepatic FAILURE?
What typically causes it?
When and with what two comorbidities will it present?
Chronic liver disease +/- compensation–>
Decreased hepatocyte # or function–> Acute Hepatic Failure
- Appears within 26 wks of initial liver injury
- Presents with coagulopathy and encephalopathy
What are the three ways that acute hepatic failure can present PATHOLOGICALLY?
- # 1: chronic liver disease changes
- massive hepatic necrosis (80-90% loss)
- non-necrotic AHF ( i.e. reye’s, preggos, drug tox)
How does Acute Hepatic Failure manifest clinically?
skin, blood, neuro?
- Jaundice (bilirubin retention) + N/ V
- Hyperammonimia
- Bx Changes, Rigidity, hyper-reflexia, EEG Changes
Describe the coagulopathy associated with acute hepatic failure: 4
- decreased clotting factor production
- ^ PT (decreased F VII)
- thrombocytopenia (marrow suppression, hypersplenism)
- DIC (failure to clear ACTIVATED factors from circulation)
What is micro vesicular steatosis and with what is it associated? What are three things that can cause this?
- Histological appearance of AHF in which fat globules fill cells bit not enough to push nuclei into periphery
- Asstd with fatty liver of PREGGOS, valproate or tetracycline toxicity
What are the lab findings associated with AHF?
- ^ AST, ^ALT
- Hypoalbuminemia
- Hyperammoemia
What are the ABCDEFs of AHF?
Acetaminophen, HepA, Autoimmune Hep B Hep C, Cryptogenic Drugs (+ toxins), Hep D Hep E, Esoterie cases (wilson's, budd chirari) Fatty changes (microvesicular type)
What happens in hepatorenal syndrome?
What will make it better?
Describe the progression…
Pre renal failure without intrinsic morphologic abnormalities; renal function will normalize with improved hepatic function
systemic vasodilation–> compensatory renal vasoconstriction–> decreased GFR
Define Chronic Liver Disease; what is the endgame?
Liver disease, abnormal testing that lasts, progressive fibrosis that lasts LONGER than 6 mos
End result = cirrhosis
Describe the pathogenesis of liver CIRRHOSIS:
Damaged hepatocyte–> ROS/ Gfs/ TNF/ IL1–>
*ACTIVATE STELLATE CELL–> TGFB, SM actin, GFAP–>
Collagen deposition–> Fibrosis–> Cirrhosis
Describe the histological path changes to the liver in liver cirrhosis: (4)
- FIBROSIS surrounding multiple adjacent lobules
- Regenerative NODULES in canals of Hering (micro)
Describe the early and late clinical manifestations of liver cirrhosis:
asx–> nonspecific (weak, anorexic) sx–> progressive liver failure–> portal HTN–> ascites, portal-systemic shunts, congestive HSM, encephalopathy
What is bile? Where is it produced?
What are its 4 functions?
Complex fluid of bile acids + bilirubin made in LIVER
Flows through biliary tract into sm intestine:
1) Emulsification + micelle formation = absorb dietary fat
2) Bicarb = neutralize gastric acid
3) Elimination: cholesterol, protein bound organic molecules, heavy metals, lipophilic metabolites
What is bilirubin? How much of bile does it comprise?
How is it clinically relevant?
What are its two forms?
Heme breakdown products; 2% of bile
- makes bruises and jaundiced people yellow
- conjugated and unconjugated
Contrast conjugated and unconjugated bilirubin:
Unconjucated: water INSOLUBLE + TOXIC; crosses BBB in babies to cause kernicterus
Conjugated: water SOLUBLE, nontoxic, excreted in urine
What are bile salts? What are the two important ones called? What is their function?
- Bile acids (cholesterol breakdown products) conjugated to Taurine or Glycine
- Cholic acid, chenodeoxycholic acid
- Act as detergents to solubilize water insoluble lipids
Cholestasis: define the term
Decreased bile flow–> accumulation of substances normally excreted in bile
95% of bile acids are reabsorbed from WHERE in the intestine and returned to the liver???
TERMINAL ILEUM
If there is an issue with excessive bilirubin production, what type of bilirubinemia would occur?
What are 3 different pathological states that could induce such bilirubinemia?
Heme–> Heme oxygenase// Biliverdinreductase–> UNCONJUCATED Hyperbilirubinemia
Potential causes:
- hemolytic anemia
- hematoma/ internal hemorrhage
- ineffective erythropoiesis (PA, thalassemia)
Failure of bilirubin uptake or binding would cause what type of bilirubinemia?
What are 4 different pathological states that could induce such bilirubinemia?
Bilirubin-Alb complex–> NOT transported across cell mb and taken up by protein carrier–>
UNCONJUCATED Hyperbilirubinemia
Potential causes:
- Hepatocellular injury
- Drugs (interference with metabolism of protein carriers)
- Physiologic jaundice of the newborn
- Gilbert’s syndrome
Failure to conjugate bilirubin in the hepatocyte ER involves failure of what enzyme?
What type of bilirubinemia will ensue?
What are 4 potential causes of such bilirubinemia?
Failure of UDP Glucuronyl Transferase–> Bilirubin NOT conjugated withglucuronic acid in ER–>
UNCONJUCATED Hyperbilirubinemia
Potential causes:
- Breast milk (???)
- Genetic UGT1A1 deficiency (Crigler-Najjar)
- Gilbert’s syndrome
- Diffuse hepatitis
Failure to excrete bilirubin will result in what type of bilirubinemia?
What are 3 potential causes of excretion failure?
CONJUGATED bilirubin diffuses through cell into bile canaliculus–> FAILS to get excreted into bile–>
CONJUGATED Hyperbilirubinemia
Potential causes:
- Dublin-Johnson, Rotor (deficient canalicular membrane transporter)
- Autoimmune cholangiopathies
- Ductal obstruction
Describe the pathway of bile cycling when excreted into small bowel:
Bile excreted into small bowel + B-glucuronidases–>
Free bilirubin + Reduction Rxn–> Pyrroles + Urobilinogen–>
80% Urobilinogen excreted in feces; 20% reabsorbed in ileum–> return to liver –> re-excreted in bile or urine
Note: B-glucuronidases come from gut bacteria
Describe the histological appearance hepatocytes affected by cholistasis within bile canaliculi:
Clusters of MQs + feathery degeneration of hepatocytes w/ clear cytoplasm
What are the clinical implications for intrahepatic vs extra hepatic cholestasis?
- Intrahepatic can ONLY be treated with liver transplant
- Extrahepatic can be cured by surgical means (less sever then transplant)
What are the clinical manifestations of the following:
1) ^ serum bilirubin
2) ^ serum bile acids
3) malabsorption of fat
4) Malabsorption of ADK
5) ^ serum cholesterol
1) jaundice
2) pruritis
3) steatorrhea
4) hemorrhaging/ clotting disorders
5) Xanthomas
List the 6 Hepatotropic viruses with affinity for the liver.
Which cause acute hepatitis?
Which cause chronic hepatitis?
What is a mnemonic for how one of the viruses can be transmitted?
A, B, C, D, E, G
Vowels A, E- NEVER CHRONIC (except HepE in preggos)
Consonants B, C, D- CAN BE CHRONIC
Hep B transmitted via Blood, Birthing, Bonking
List 5 viral infections that are not specifically hepatotropic but can cause hepatitis:
- EBV, CMV, HSV
- Adenovirus (immunosuppressed, neonates)
- Yellow fever
I remember HAYCE viruses.
Which hepatitis virus is more often chronic than not?
Hepatitis C
- 80% get chronic disease
- 20% of ppl w chronic disease will develop cirrhosis
Describe the typical course of ACUTE viral hepatitis (what are the 4 stages of infection?):
- Weeks 1-2: Incubation (asx + most infectious towards end)
- 2 wks: Symptomatic Pre-Icteric (flu sx)
- 4 wks: Icteric (jaundice, dark urine, clay stool, HM), lasts 6 wks
- 6-8wks: Convalescence (less jaundice)
Describe the lab findings asstsd. with ACUTE viral hepatitis:
- ^ transaminases
- hyperbilirubinimia
- viral serology
Define CHRONIC viral hepatitis:
ANY evidence of continuing/ relapsing disease lasting LONGER than 6 mos
Describe the carrier state for viral hepatitis:
Harbor organism without signs or sx of infection; patient is a RESERVOIR for future infection
How is hepatocellular damage mediated in viral hepatitis?
Mediated by T CELL DEFENSE MECHANISM:
T cells activated in response to infected cells–>
Necroinflammatory activity + Apoptosis
HAV:
Family, Genus, Genome, Envelope?
How is the virus transmitted?
Family: Picornaviridae
Genus: Hepatovirus
(+) ssRNA, Naked
Fecal oral transmission (water, shellfish*)
Describe the differences in infection caused by Hep A in endemic developing countries vs. developed countries
Endemic countries: Poor sanitation; MILD CHILDHOOD disease (most have immune Abs by 10yoa)
Developed countries: No herd immunity; more SEVERE ELDERLY DISEASE
Describe the Ab response to Hep A infection; which Igs are made first? Which are made later?
Which can be directly detected?
Acute symptomatic infection–> ^ IgM
IgM declines over mos–> ^ IgG confers lifelong immunity to ALL STRAINS of Hep A
IgG CAN NOT be directly detected
When does fecal shedding of HAV occur?
- 2-3 weeks BEFORE jaundice
- 1 wk AFTER START jaundice
F/O or close contact with infected individuals during this time period is how infection spreads
How do we diagnose HepA infection? Is there a carrier state? De we biopsy the liver? How often do patients relapse infection?
- Hx of travel to endemic areas
- Exclude drug-induced disease (Acetaminophen OD)
- Do not biopsy liver
No chronic or carrier state, rarely relapse
HBV:
Family, genome, structure
Describe the 3 important antigens.
Hepadinaviridae
- Circular dsDNA
- Enveloped
- Carries DNA pol, reverse transcriptase
- Hbx protein = transcriptional activator
HbcAg = core antigen HbsAg = surface/ envelope glycoprotein antigen HbeAg = indicates infectivity
What is the dane particle?
Dane pareticles are small, sausage shaped surface antigens (virons) that infect hepatocytes
Describe the course of Ig production in HBV infection; which are made first and which are made later?
IgM made at first–> IgG made agains HbcAg after several mos infection
**Note IgM is always the first Ig made in response to infection :)
Describe how mode of HBV transmission is influenced by geography (high, medium, low prevalence regions)
- Vertical transmission (parturition) in ^ prevalence regions
- Horizontal transmission intermediate prevalence regions
- Sexual/ IV drug transmission in LOW prevalence regions
Describe the typical course of HBV disease.
How common is chronic disease and what risks does it pose?
Who is more likely to get chronic HBV infection?
How is infection cleared?
- Typically self limited, spontaneous resolution/ recovery
- Chronicity = RARE; ^ risk HCC
- Chronicity more likely in YOUNGER patients + immunocompromised (i.e. vertical transmission to baby)
**Patients will clear infection if CD4, CD8 cells make IFN-Y and clear infected cells (like all viral infections?) Failure = chronicity
Why is a complete cure to HBV difficult to attain?
How do we treat disease?
Virus inserts itself into host DNA–> inhibits effective immune response via production of HbsAb–> infection persists
Only treatment is to slow infection and limit cirrhosis/ progression to HCC
HCV:
Family, genome, structure?
What accounts for the variety of HCV genotypes?
Flavaviridae
(+) ssRNA, enveloped, codes for 1 polyprotein that gets cleaved
*RNA-Pol has poorfidelity–> multiple genotypes and subtypes get made
Why is it difficult for us to develop a HCV vaccine!?
E2 envelope protein = target for anti-HCV Abs
- *E2 envelope protein is the MOST VARIABLE region of the genome sequence; thus it commonly escapes neutralizing Abs
- *^^ genomic instability/ antigenic variability = IMPOSSIBLE TO MAKE VACCINE
Why is there such a high rate of chronicity in HCV infection?
IgG made after HCV infection DOES NOT confer immunity (high genomic instability of HCV)–> recurrent reactivation of preexisting infection/ emergence of mutated strain are common events
What are the two most common means if HCV infection in the US?
How common are transfusion related infections?
Are you more likely to get HCV or HIV from needle stick?
What % HCV infections are perinatally transmitted?
#1 = IV drug use #2= (Unprotected) sexual promiscuity
- Transfusion associated infections ~ 0 bc good screening
- More likely to get HCV than HIV from a needle stick
- Perinatal infection accounts for 6% HCV (vs. 20% HBV)
Describe the clinical course of HCV infection; how severe is the clinical course?
4-26 wks Incubation (asx)–>
HCV RNA in blood + ^AST/ ^ALT for 1-3wks–>
Chronic hepatitis–> 20% Cirrhotic
How is HCV treated?
Which viral genotypes respond best to treatment?
Which host genotypes respond best to treatment?
- Pegylated IFN-a
- Ribavirin
Viral genotypes 2, 3 = Best
Host genotype IL28B (IF-lambda) = Best
Rx QUESTION; make sure you know which IFNs are use to treat which things i.e. “a” for viruses like HCV “b” for MS, etc. I’m sure you know but this was just a friendly reminder
Yes, I remember, Inf-BETA treats the BRAIN in MS. B for Brain, which means A is NOT the brain, it is the virus one. And gamma is for random shit
What is an absolute requirement for HDV infection?
HBV infection!
Describe the course of HDV infection; how about confection w HBV?
How can you get an HDV superinfection?
- Typically self limited EXCEPT in IV drug abusers (ACUTE LIVER FAILURE)
- HBV confections are typically ACUTE and self limited
HDV SUPERINFECTION results when patient carries HBV and gets infected with HDV 30-50 days later–> SEVERE ACUTE HEPATITIS
Describe the HDV genome.
How does the virus replicate?
What is the antigenic target for the host’s immune system?
- ssRNA genome replicates using HOST RNA-pol
- Delta Antigen (HDAg) targeted by host immune system (there is a small and a large)
Where is HEV epidemic?
Where are the more more HEV than HAV cases?
Where is HEV harbored in developed countries?
Which population is exceptionally vulnerable to HEV infection?
Epidemic in Asia, Africa, ME, Mexico
India has more HEV than HAV
Developed countries harbor HEV on pig farms
**PREGGOS GET HEV REALLY BAD!
HEV: Family, genome When are the virons shed? What do the labs look like during clinical infection? Describe the clinical course?
Hepeviridae; (+)ssRNA
- Virons shed detectible in stool + serum prior to sx; shed throughout acute illness
- Labs: ^AST/ALT + IgM Anti-HEV
- Self limited infection lasts 4-6wks
How is a liver biopsy different based on different causes of hepatitis?
It isn’t; liver biopsies are the same whether hepatitis is viral, autoimmune, or drug induced
**Need clinical hx to dx cause
EXCEPT PLEASE NOTE: SHE DOES WRITE THIS, BUT BECAUSE SHE IS AN ACTUAL BITCH……
-Per Basem: “In her review, she stated, you should look at robbins/ be able to differentiate Hep B and C on histo.” (He posted a picture of this to FB if you do not have robins/ cannot find it online.)
What are the uses for liver biopsy? (4)
- confirm dx
- exclude simultaneous conditions (i.e. drug induced)
- extent of inflammation, injury, fibrosis
- monitor treatment effectiveness
Ground glass pattern hepatitis is associated with which cause?
HBV
What infectious agent will cause hepatitis with cowry bodies?
HSV hepatitis (bc cowry’s are HSV)
What kind of hepatitis will cause apoptotic bodies?
Viral causes of hepatitis will yield apoptotic bodies
Define autoimmune hepatitis. What are the typical lab findings associated with this disease? What is found on liver biopsy? What is the definitive Dx? Is there a good treatment? What is the prognosis of disease?
Idiopathic CHRONIC, progressive autoimmune attack of hepatocytes
- ^ AST, ALT + serum autoAbs, polyclonal serum Igs
- NECROINFLAMFMATION on liver biopsy
- Definitive dx = BIOPSY
- Excellent response to immunosuppressants
- WILL DIE WITHOUT TREATMENT
Which population has the highest incidence of autoimmune hepatitis?
With northern european females (but really anyone can get it)
What is Type 1 autoimmune hepatitis? Who gets it? What are the serologic markers (2)?
Type I autoimmune hepatitis is found in middle aged/ older adults in the US
- ANA
- ASMA (anti-smooth muscle Ab)
What is Type 2 autoimmune hepatitis? Who gets it? What are the serologic markers (1)?
Type II autoimmune hepatitis is found in KIDS + TEENS in southern europe
- Anti-LKM-1 (attacks CYP-2D6 on plasma mb of cell)
Describe the three potential etiologies behind autoimmune hepatitis:
- idiopathic
- environmental trigger (drug/ infection)
- genetic predisposition (HLA association established)
What are the three ways that autoimmune hepatitis might present?
- Asymptomatic incidental finding
- Asstd. w other autoimmune diseases
- Acute hepatitis w/ flu like sx
- Fulminant Hepatitis w. encephalopathy
- Overlap syndrome (AIH-PBC, AIH-PSH) w biliary disease
- Cirrhosis
Describe the course of treatment for AIH:
Immunosuppression with prednisone or asothioprin; type 2 non responders may dry different treatments
50% will relapse on treatment withdrawal, therefore treatment is a life-long process
Patients may require transplant (20% transplant recipients recur)
What are Xenobiotics and how are they relevant to the liver?
These are therapeutic agents and environmental toxins that are metabolized in the liver via immune mechanisms (possibly to toxic compounds)
Can cause cholestasis–> fulminant hepatitis
How do we identify if liver injury is associated with xenobiotics? (2)
- temporal association w exposure and injury
- recovery upon withdrawal of the agent
Describe the histo changes and liver injury caused by OCPs (2 potential problems):
Cholestatic injury OR Vascular lesions
Cholestatic Injury: Bland hepatocellular cholestasis without inflammation (feathery degeneration)
Vascular lesions: Budd chirari syndrome, pelliosis hepatitis (blood filled cavities WITHOUT endothelial lining)
Describe the histo chances and liver injury caused by acetaminophen toxicity:
- Hepatocellular necrosis
- Spotty necrosis, massive necrosis, or chronic hepatitis changes
Describe how MTX can hurt the liver (histo and type of injury):
- Fatty liver disease OR fibrosis/cirrhosis
- FLD: large + small droplets fat seen on histo
Describe the histo changes and liver injury associated with ETOH abuse?
Fatty liver disease
- Large/ small fat droplets OR…
- Steatohepatitis with Mallory-Denk bodies
Which two xenotoxins are capable of causing fibrosis and cirrhosis? How does this look on histo?
Alcohol (not necessarily just ETOH, but “Alcohol”) and MTX
- Periportal + pericellular fibrosis
OCPs can cause what hepatic neoplasm?
hepatic adenoma
Alcohol can cause what hepatic neoplasms? (2)
- hepatocellular carcinoma
- cholangiocarcinoma