Chapter 18: Liver Flashcards
- Which 3 serum enzyme measurements represent a response to disrupted hepatocyte integrity?
- Aspartate aminotransferase (AST)
- Alanine aminotransferase (ALT)
- Lactate dehydrogenase (LDH)
- ___________ measure the biliary excretory function.
- Serum bilirubin
- Urine bilirubin
- Serum bile acids
- Serum measurements of which 2 enzymes look for damage to bile canaliculus?
- Serum alkaline phosphatase (ALP)
- Serum gamma-glutamyl transpeptidase (GGT)
- What are the tests that look for hepatocyte synthetic function (synthethesis)?
- Serum albumin
- Coagulation factors: PT, PTT, fibrinogen, prothrombin, factors V, VII, IX, and X
- Hepatocyte metabolism:
- serum ammonia (↑ in L.D)
- aminopyrine breath test (hepatic demethylation): (↓ in L.D)
As liver function decreases = coag levels ______ = PT levels _____
- decrease
- increase
Alcoholic liver disease:
↑ ____ > ↑ ____
↑ AST > ↑ ALT (2:1)
Most types of hepatitis that damages hepatocytes
↑ ____ > ↑ ____
↑ ALT > ↑ AST
Alkaline Phosphotase (ALP) is a __________ that measures _________.
Enzyme from liver, bones and GI tract;
- ↑ when bile flow is obstructed (cholestasis) =
- can also rise in pregnancy (placenta); thyroid disease and bone disease
To determine if an ↑ in ALP is due to liver, biliary tree or bones, we measure _____.
GGT = ↑ in cholestasis and biliary obstruction, does not rise in bone disease.
- ↑ ALP & ↑ GGT = ______ cause.
- ↑ ALP & NL GGT = ____ cause.
- Hepatobiliary
- Bones
- 2 reversible changes in hepatocytes (2)
- Steatosis: accumulation of fat in the liver
- Cholestasis: accumulation of bilirubin in the liver
When injury is not reversible, hepatocytes die via ______ or ______.
- Necrosis
- Apoptosis
_________ is the predominant mode of hepatocyte death seen in ischemic/hypoxic injury and responses to oxidative stress. Describe this mechanism.
Necrosis;
- Defect in osmotic resgulation causes fluid to enter the cell => cell swells and ruptures (lysis)
- MO accumulate at sites of necrosis
____________ is the type of cell death seen in acute and chronic hepatitis. Describe the process.
Apoptosis.
- Hepatocyte shrink
- Chromatin condenses (pyknosis)
- Fragmentation (karyorrhexis)
- Cellular fragmentation into acidophilic apoptotic bodies (adidophil bodies)
________ increase at sites of hepatocyte injury and mark sites of hepatocyte necrosis.
MO
Councilman bodies are the apoptotic bodies associated with what disease?
Yellow Fever
When there is widespread parenchymal loss, there is often evidence of ___________.
When does this occur?
Confluent necrosis; severe zonal loss of hepatocytes.
- Begins as a zone of hepatocyte dropout around the central vein.
- Produce a space filled with cellular debris, MO, and remnants of the reticular meshwork
Occurs in: acute toxic injury, ischemic injury, viral/AI hepatitis.
What is bridging necrosis?
What disease do we see this in?
- Vascular insult (inflammation or thrombosis) causes zonal loss of hepatocytes to occur in between [central veins - portal tracts; portal tract - portal tract] => parenchymal extinction and collapse of the supporting network.
- Cirrhosis
Regeneration of the liver occurs via 2 major mechanims, which are?
What is the predominant method?
1) Proliferation of hepatocytes adjacent to those that have died ***
2) Stem cell replenishmenemt
Is stem cell replenishment a big part of parenchymal repair when hepatocytes are regenerating?
- NO
- However, hepatocytes are almost stem-cell like; they can continue to replicate even in the setting of years of chronic injury.
When do stem cells begin to contribute significantly to restoring the liver parenchyma?
In chronic diseases via ductal reactions (heptocytes reach replicative senescence => + of stem cells => form ductular reactions => restore parenchyma).
__________ is the main type of liver cell involved in scar deposition => cirrhosis.
Stellate cell.
- NL: stellate cells are dormant and store lipids (vitamin A).
- However, when there it acute or chronic injury, they becomes fibrogenic myofibroblasts => secrete TGF-B and initiate fibrosis.
Describe the process of activation of stellate cell from a lipid-storing cell => fibrogenic myofibroblast => fibrosis.
-
-
Kupffer cells are + => release mutuple cytokines:
1. PDGF-B and TNF (others: TGF-B, MMP-2 and TIMP-1/2) => proliferation and (+) stellate cells (lipid-storing => myofibroblasts).
2. Stellate cells transform into myofibroblasts that contract when stimulated by ET-1 (endothelin-1)
3. Chemotaxis of + stellate cells to areas of injury are promoted by PDGF and MCP-1 (Monocyte chemotactic protein-1.
- Stellate cells begin to secrete TGF-B => produce collagen and initate fibrosis.
-
Kupffer cells are + => release mutuple cytokines:
What stimulates (+) of stellate cells & scar formation?
- Chronic inflammation, with production of inflammatory cytokines (TNF, IL-1B and lymphotoxin)
- Cytokines and chemokines made from Kupffer cells, endothelial cells, hepatocytes and bile duct epithelial cells
- Disruption of ECM
- Direct stimulation by toxins
If injury persists => scar deposition begins, often in the Space of Disse .
In chronic inflammation which inflammatory cytokines are made and act as stimuli for Stellate Cell activation?
- - TNF
- - Lymphotoxin
- - IL-1β
What role does ductular reactions have in scar deposition?
- and recruit fibrogenic cells
- Epithelial-mesenchymal transition
If the chronic liver injury leading to scar formation is interrupted (i.e., clearance of hepatitis virus infection, cessation of alcohol use), what happens?
Scar formation reverses.
- Stellate cells stop being activated
- Scars condense –> become more dense and thin
- Metalloproteinases produced by hepatocytes break the scar apart.
When does liver failure occur?
Without a liver transplant, the mortality rate is _____.
- When 80-90% of hepatic function is lost.
- 80%
Liver failure may be due to what 3 reasons?
1. Acute injury
2. Chronic, progressive injury*
3. Acute-on-chronic injury
What is acute liver failure?
Acute liver illness associated with encephalopthy and coagulopathy that occurs within 26 weeks of the initial liver injury, in the abscence of a pre-existing disease.
Acute live failure is caused by what type of tisuse injury?
Massive hepatic necrosis, often due to drugs/toxins.
What is the major cause of acute liver failure in the US?
What accounts for the rest of cases?
- Acetominophen OD (accidental or deliberate) => 50%
- Autoimmune hepatitis
- Drugs/toxins
- Acute HepA and B
What are all causes of Acute Liver Failure?
MNEUMONIC
- A: Acetominophen, HepA, AI hepatitis
- B: Hep B
- C: Hep C; cryptogenic
- D: Drugs/toxins, HepD
- E: Hep E, esoteric causes (Wilson’s Disease, Budd-Chiari disease)
- F: Fatty changes of the microvascular type (fatty liver of pregnancy, valproate, tetracyclin, Reyes syndrome)
How quickly does liver failure occur with acetominophin toxicity vs. hepatitis?
- In acetominophen toxicity, LF occurs within one week of the onset of sx’s.
- LF in hepatitis takes longer to develop.
What is the morphology of Acute Liver Failure?
- Microscopic?
- Gross?
- Scar formation and ductular reactions?
- Massive hepatic necrosis with broad regions of parenchymal loss around islands of regnerating hepatocytes.
- Small and shrunken
- Scar formation & ductular reactions depends on the type and duration of insult:
- Toxic injuries = like acetominophen = failure occurs hours to days = too short to allow scars to form
- Acute viral injuries = failure occurs from weeks - months = hepatocyte injury outweighs repair = early scarring occurs in areas of parenchymal loss
Rarely, in acute liver failure diffuse microvesicular steatosis can occur.
What is this and what disorders is this commonly seen in?
- Small intracytoplasmic fat vacuoles (liposomes) accumulate in the cell => poison, without causing cell death and parenchymal collapse.
- Occurs in fatty liver of pregnancy or reactions to toxins (tetracycline/ valproate)
Diffuse microvesicular steatosis causes intracytoplasmic accumulation of liposomes, causing hepatocytes not to be able to perform their metabolic function due to…
Damage to the mT
Which 4 viruses are most often the cause of acute liver failure in patients who are immunodeficient?
- 1. HIV
- 2. CMV
- 3. HSV
- 4. Adenovirus
Clinically, what symptoms do we see in a patient with acute liver failure?
- Jaundice and N/V => progresses to life-threatening encephalopthy and coagulopathy
- Moderate increase in liver transaminases
- Hepatomegaly (d/t swelling, infiltrates and edema) => parenchyma is destroyed => shrunken liver and ↓ in serum transamineases bc less viable hepatocytes
When does acute liver failure = poor prognosis?
- ↓ in liver enzymes, meaning that we have a few remaining hepatocytes,
- Jaundice, coagulopathy and encephalopathy worsens
What are other manifestations of acute liver failure? (5)
- Jaundice, icterus and cholestasis
- Hepatic encephalopthy
- Coagulopathy
- Portal HTN (most common in chronic LF)
- Hepatorenal syndrome
Cholestasis increase the risk of _____.
Life-threatening bacterial infection.
What is hepatic encephalopthy?
- ↑ levels of ammonia => disturbances in consciousness (ranging from behavioral abnormalities => confusion => deep coma and death).
What is a characteristic sign of Hepatic Encephalopathy?
How does it present?
- Rigidity and hyperreflexia
- Asterixis = nonrhythmic, rapid extension-flexion movements of head and extremities
- Best seen w/ arms in extension w/ dorsiflexed wrists
Which disorders of coagulopathy may be seen in acute liver failure?
Earliest sign?
- Liver is responsbile for making Vit K dependent clotting factors and other CF. LF = > no clotting factors =>
- Earliest sign is easy bruising => can lead to fatal intracranial bleeds
- Liver also removes activated coagulation factors from blood.
- If fx is lost => Disseminated intravascular coagulation (DIC) => a condition in which blood clots form throughout the body, blocking small blood vessels. As clotting factors and platelets are used up, bleeding may occur.
Portal HTN is more common in chronic liver failure, but if it occurs in acute liver failure, it is most likely due to ______________ , which can cause ________________.
- Intrahepatic obstruction
- Ascites and hepatic encephalopathy
What is hepatorenal syndrome?
The syndrome’s onset begins with a drop in what and rising?
- A form of renal failure in people with liver failure, whose kidneys are NL.
- Decreased renal perfusion pressure/GFR => renal vasoconstriction => Na+ retention and impaired free-water excretion.
- *Begins w/ a ↓ in urine output + ↑ BUN/Cr.
Does all cirrhosis lead to chronic liver failure and is all end-stage chronic liver disease cirrhotic?
No. Although, they are often associated with one another.
What are the most comon causes of chronic liver failure?
- Chronic HepB/C
- Non-alcoholic fatty liver disease (NAFLD)
- Alcoholic fatty liver disease
What is cirrhosis?
Formation of regenerative nodules on the liver parenchyma surrounded by:
- Bands of fibrotic tissue
- Vascular shunting (often portosystemic).
___________ describes cirrhosis when there is no clear cause.
Cryptogenic cirrhosis
What are the 3 morpphological characteristics of cirrohosis?
- Bridging fibrosis links portal tracts to each other and to central veins
- Parenchymal nodules due to hepatocyte regeneration when encircled by fibrosis.
- Disruption of the architecture of the parenchyma.
What is the Child-Pugh classification of cirrhosis?
Monitor the track of decline in patients with chronic liver failure.
- *Class A (well compensated);
- Class B (partial comp.);
- Class C (decompensated)*
As chronic liver disease worsens, ductular reactions _____.
- They occur most often in ______.
Increase
Cirrhosis
Why is cirrhosis no longer considered end-stage liver diasese?
- the fibrosis is potentially reversible with increasing numbers of effective treatments for cirrhosis-causing conditions
On biopsy, what do we see that is most likely linked to end-stage disease?
- Broad bands of dense scar
- Dilated lymphatic spaces
- Less parenchyma
are more likely to progress to portal HTN and thus, end stage disease.
When do patients with cirrhosis become symptomatic?
40% of individuals with cirrhosis are asymptomatic until the most advanced stage of the disease.
What are the clinical symptoms of cirrhosis (chronic liver failure)?
- Chronic jaundice + intense pruritus => pt may scratch skin raw.
- Hypoalbuminemia –> systemic edema
- Hyperammonemia -> heptic encepholopathy
- Fetor hepaticus: mercaptan formation
- Males have problem metabolizing estrogen => hyper-estrogenemia => palmar erythema, spider angiomata, hypogonadism*, and gynecomastia
- Portal HTN => ascites
- increased risk of developing hepatocellular carcinoma
* = can also occur in W
In men, what are the adverse effects of impaired estrogen metabolism and consequent hyperestrogenemia associated w/ chronic liver disease?
- Palmar erythema
- Spider angiomas
- Hypogonadism and Gynecomastia
Portal HTN = Increased resistance to portal blood flow.
What 3 categories are causes of portal HTN?
- Prehepatic causes
- Intrahepatic causes
- Posthepatic causes
What are pre-hepatic causes of portal HTN?
- Obstructive thrombosis
- Narrowing of the portal vein before entering the liver
- Massive splenomegaly with increased splenic blood flow
What are the post-hepatic causes of portan HTN?
- Severe right heart failure
- Constrictive pericarditis
- Obstruction of hepatic vein outflow
What is the most common intrahepatic cause of portal HTN?
Cirrhosis
What are the mechanisms that Cirrhosis causes edema and ascites?
In cirrhosis,
- ↓ in albumin => ↓ in oncotic pressure => ↓ in effective circulating volume.
- ↑ in many vasodilators (NO) => splanchnic vasodilation => ↓ in SVR and BP => sympathetic + and ↓ in effective circulating volume
- 3. ↓ in effective circulating volume => ↑ RAAS and ADH => ↑ in Na/H20 => ↑ in total body water.
- => acites and edema.
*
- => acites and edema.
MCC of portal HTN is cirrhosis.
What are other intrahepatic causes?
- Schistomiasis
- Massive fatty change
- Granulomatous disease (sarcoidosis)
- Nodular regenerative hyperplasia
The pathophysiology of portal HTN develops due to what 2 causes?
NL path of blood?
NL, blood froms from portal vein => liver => hepatic vein => systemic. Cirrohosis causes obstructed BF through liver.
- ↑ in blood flow via portal vein to the liver.
- ↑ pressure in portal vein at the level of the sinusoids due to cirrhosis causing obstructed BF in the liver.
What are the clinical consequences of portal HTN? (4)
↑ pressure in the portal veins => fluid leaks out
- Ascites
- Congestive splenomegaly
Circulatory system starts to dlvert blood away from the liver via a portosystemic shunt (bc blood flow follows the path of least resistance), shunting blood away from the portal system => to systemic system of circulation.
- Formation of a portosystemic venous shunt
- Hepatic encephalopathy = bc less functional
units = liver cannot detoxify
- Ascites is collection of excess ____ fluid in the peritoneal cavity, clinically detectable when ______ has accumulated.
- In 85% of cases, it is caused by _______.
- Long-standing ascites can cause what?
- Serous; 500mL
- Cirrhosis
- Hydrothorax: peritoneal fluid seeps through trans-diagphragmatic lymphatic channels, especially on the R.
What is the composition of fluid seen in ascites?
- Serous fluid w/ < 3g/dL of protein (mainly albumin);
- Little # of mesothelial cells and mononuclear leukocytes
_______ in the fluid in ascites can indicate an infection; while ______ can indicate disseminated intraabdominal cancer.
- Neutrophils = ascites
- Blood = disseminated intraabdominal cancer
What are the 3 mechanism which account for the pathogenesis of ascites?
- Sinusoidal HTN/portal HTN [+/-] hypoalbuminemia
- Percolation of hepatic lymph into the peritoneal cavity
- ↑ in many vasodilators (NO) => splanchnic vasodilation => ↓ in SVR and BP => ↓ in effective circulating volume & sympathetic (+) => triggers vasoconstriction & RAAS + => Na+ and H20 retention => increase in TBW
Q: Patient presents with cirrhosis, but not portal HTN, will they develop ascites, edema or both?
Only edema; portal HTN must be present for ascites to develop.
Q: If you see a patient presenting with ascites, you KNOW that they have ______.
Portal HTN
What do SAAG levels measure?
How does it measure it?
Whether ascites is due to portal HTN or malignancy, which causes leaky vasculature.
- Measure SAAG: paracentesis of fluid in ascites (serum albumin - ascites albumin = SAAG)
-
SAAG >1.1 g/dL = portal HTN.
- Large difference between serum and ascites albumin because high pressure in portal system is driving fluid into the peritoneum, not albumin.
-
SAAG <1.1 g/dL = malignany ascites.
- Levels of albumin levels are similar between the serum and ascites = leaky vasculature leads to fluid/albumin into peritoneum.
Portal HTN causes the formation of portosystemic shunts. What are these?
- Pressure in portal vein is high, as a result, flow is reversed into the systemic circulation through venous collaterals (connections between venous and portal veins). = engorge in portal HTN.
What are the portosystemic shunts (key collaterals) that engorge in portal HTN and what do they result in?
Swelling of venous collaterals around the:
- BB & falciform L of the liver => caput medusae
- Esophagus => esophgeal varices => UGIB
- Stomach => gastric varices
- Rectum => internal hemorrhoids.
What is responsible for massive hematemesis and death in pts with advanced cirrhosis of the liver?
- Esophageal varices, which occur in 40% of people with advanced cirrhosis.
Splenomegaly due to portal HTN may cause what?
- Thrombocytopenia –> ↓ platelet count
- Pancytopenia –> ↓ RBC/WBC + platelets
What are 2 other conditions that occur in Chronic Liver Failure?
- 1. Hepatopulmonary syndrome
- 2. Portopulmonary HTN
- Hepatopulmonary Syndrome occurs in 1/3 of patients w/ cirrhosis and portal HTN.
- What is the pathogenesis?
- Patients develop intrapulmonary vasodilation =>
- ↑ blood flow =>
- ↓ O2 diffusion of blood =>
- V/Q mismatch =>
- Hypoxia (dyspnea that is worse when standing) and is best in recumbant position.
What are the 2 most common clinical manifestations of Portopulmonary HTN?
1) Dyspnea on exertion
2) Clubbing
What is acute-on-chronic liver failure?
- Ppl with stable, well-compensated chronic liver failure develop sudden signs of acute liver failure.
- Develops d/t large amounts of the liver having borderline vascular function and vulnerable to superimposed insults.
Viral hepatitis refers to
Infection by Hepatitis A-E.
All viral hepatitis are ____ viruses, except ______, which is _____.
- RNA viruses
- Except HepB => partial DNA
Which Hepatitis are transmitted fecal-orally?
Hep A and E
Fulminant hepatitis (acute liver failure) is unusual, but is seen primarily with which hepatitis viruses?
- A
- B
- D
- *HEV in pregnant women
Hepatitis A
- Type of virus:
- Viral family:
- Route of transmission:
- Mean incubation period:
- Frequency of chronic liver disease:
- Carrier state?
- Diagnosis:
- Small, naked +ssRNA
- Picornavirus
- Fecal-oral via contaminated water in developing countries; eating raw or steamed shellfish that was contamined in seawater with sewage in developed countries
- 2-6 weeks
- Never: benign, self-limited and rarely lethal.
- No carrier state
- Onset of sx =
- IgM Ab = acute infection
- Within a few months, as IgM Ab ↓ => IgG Ab ↑ and persist for years => confer immunity.
Which immune cell appears to play the key role in the hepatocellular injury caused during Hep A and B infection?
CD8+ cytotoxic T cells => kill virus infected cells.
Case: Travelor who goes to MX/ Central America
HepA
Hepatitis E
- Type of virus:
- Viral family:
- Route of transmission:
- Mean incubation period:
- Frequency of chronic liver disease:
- Carrier state?
- Diagnosis:
- Type of virus: naked (+) ssRNA
- Viral family: Hepevirus
- Route of transmission: Enterically via fecal-oral from contaminated water in young-middle aged adults.
- Mean incubation period: 4-5 weeks
- Frequency of chronic liver disease: NEVER; self-limited => virions are shed in shit during acute illness.
- Carrier state? -
- Diagnosis: Serum IgM and IgG; PCR for HEV RNA
What is the reservoir in Hep E?
- Animals: increased risk with exposure to monkeys, cats, pigs, and dogs
What is a UNIQUE characteristic feature about HepE?
- High mortality rate in pregnant women (20%)
Hepatitis B
- Type of virus:
- Viral family:
- Route of transmission:
- Mean incubation period:
- Frequency of chronic liver disease:
- Fulminant hepatitis?
- Diagnosis:
- Enveloped, partially dsDNA (circular)
- HepaDNAvirus
- Parenteral, sexual contact, perinatal
- 8 weeks
- 5-10%
- YES
- Detection of HBsAg, antiHBcAg; PCR for HBV DNA
Even in the absence of cirrhosis, chronic infection by which viral hepatitis is an important precursor for the development of hepatocellular carcinoma?
Hepatitis B
What are the 5 different forms of HBV illness?
- Acute hepatitis => recovery and clearance of the virus
- Non-progressive chronic hepatitis
- Progressive chronic disease resulting in cirrhosis & ↑ risk of HCC
- Fulminant hepatitis (acute LF) with massive liver necrosis
- Asymptomatic, ‘healthy’ carrier state
In high prevalence areas of HBV, like Africa & Asia, what is the major mode of transmission?
Transmission during childbirth
What is the most common mode of transmission for HepB in areas with intermediate prevalence and areas with low prevalence?
- Intermediate: horizontal transmission in early childhood by minor breaks in skin or mucous membranes
- Low (USA): unprotected sex and IV drug abuse (sharing needles)
Which mature hepatitis virus, when intact, is referred to as the “Dane particle?”
HepB Virus
What is unique about the replication cycle of HepB?
Mediated by what?
- Contains Pol, which has both DNA polymerase and reverse transcriptase activity
- Partial dsDNA —> dsDNA => mRNA —> makes proteins, such as reverse transcriptase, which converts it back into partial dsDNA => packaged into virions.
What is the structure of a HepB virus Dane Particle?
Virus has antigens (BAD):
- HBsAg (HepB surface antigen)
- Capsid is made up of
- HBcAg (HepB core antigen), which stays in hepatocytes and does not circulate in blood, to help with the assembly of complete virions
- HBeAgs (HepB e Antigen), which is released during viral replication
- Partially dsDNA in the center, with its own DNA polymerase to complete double-stranding of the genome once the molecule gets into the nucleus.
Each AB targets only a single type of antigen, proteins found on BAD SHIT: viruses, bacteria, funguses, cancer or even bodies own cells (in AI diseases).
Job of AB is to go hunt down antigen and attack it.
Which HepB antigens can be detected in the blood?
1. HBsAg
2. HBeAg
Which HepB antibodies can be measured in the blood?
- Anti-HBsAg
- Anti HBeAg
- Anti-HBcAg
- _______ ↑ in acute disease and ↓ as infections resolves.
- _______ ↑ as acute infection resolves.
- Antigens ↑ in acute disease and ↓ as infections resolves.
- Antibodies ↑ as acute infection resolves.
In HepB, _______ appears in the blood before the onset of symptoms and tells that the person is infected (acute or chronic) or not.
HBsAg
- (+): person is infected (acute, chronic or carrier)
- (-): person is not infected
How do we know a ID a person who was vaccinated with HepB vaccine?
Vaccine => administer HBsAg to patient.
- + Anti HBsAg (antibodies to HBs antigen)
- All other AB (HBc, HBe) should be negative.