Ch. 18 1-3 (Dobson) Flashcards
What are the serum measurements for hepatocyte integrity (tells us if there is liver damage, NOT function)?
- Aspartate aminotransferase (AST)
- Alanine aminotransferase (ALT)
- Lactate dehydrogenase (LDH)
What are the tests that look for biliary excretion function?
- Serum bilirubin
- Urine bilirubin
- Serum bile acids
What are the tests that look for damage to the bile canaliculus?
- Serum alkaline phosphatase
- - Serum gamma-glutamyl transpeptidase (GGT)
What are the tests that look for hepatocyte synthetic function?
– Serum albumin
– Coagulation factors: PT, PTT, fibrinogen, prothrombin, factors V, VII, IX, and X
– Serum ammonia (hepatocyte metabolism)
What are the REVERSIBLE changes in hepatocytes?
- Steatosis = accumulation of fat in liver
- - Cholestasis = accumulation of bilirubin in liver
Within the lobule, hepatocytes are organized into anastomosing sheets or “plates” extending from portal tracts to the terminal hepatic veins. Between the trabecular plates of hepatocytes are vascular ________.
Sinusoids
Blood traverses the sinusoids and exits into the terminal hepatic veins through numerous orifices in the vein wall. Hepatocytes are thus bathed on two sides by well-mixed, _______ ______ and _______ ______ blood.
Portal venous
Hepatic arterial
The sinusoids are lined by fenestrated endothelial cells. Beneath the endothelial cells lies the _______ ______ ______, into which protrude abundant hepatocyte microvilli.
Space of Disse
Scattered _______ cells of the mononuclear phagocyte system (macrophages) are attached to the luminal face of endothelial cells, and fat-containing myofibroblastic _______ _______ cells are found in the space of Disse.
Kupffer
Hepatic stellate
Between abutting hepatocytes are _______ ______, which are channels 1 to 2 um in diameter, formed by grooves in the plasma membranes of facing hepatocytes and separated from the vascular space by tight junctions.
Bile canaliculi
Bile canaliculi drain into the _______ _______ _______ that, in turn, connect to Bile Ductules in the periportal region. The ductules empty into the terminal Bile Ducts within the portal tracts.
Canals of Hering
Large numbers of _________ are also present in normal liver, comprising as much as 22% of cells other than hepatocytes.
Lymphocytes
What are the 4 main functions of the liver?
- Energy generation and substrate interconversion
- Synthesis and secretion of plasma proteins
- Solubilizing, transport, and storage functions
- Protective and clearance functions
T/F. Hepatic damage also occurs secondary to some of the most common diseases in humans, such as heart failure, disseminated cancer, and extra-hepatic infections.
True
Hyperbilirubinemia or jaundice is defined by elevated levels of bilirubin in the bloodstream. This condition may be classified due to ________, ________, or _______ disorders.
Prehepatic
Intrahepatic
Posthepatic
This type of bilirubin is attached to albumin and taken to the liver.
Unconjugated (Indirect)
***Remember, it is INSOLUBLE!
This type of bilirubin is released from the liver into the bile canaliculi to form bile, which is then stored in the gallbladder.
Conjugated (Direct)
This lab test is particularly sensitive for liver disease. If the level is normal, there is only 1-2% chance of liver disease being present.
GGT
The levels of AST and ALT are also very useful for the diagnosis of liver disease. An _______ >3000 U/L suggests a severe hypotensive episode causing centrilobular necrosis, a toxic injury such as acetaminophen overdose, or acute viral hepatitis.
AST
T/F. Chronic diseases of the liver such as alcoholic liver disease and chronic viral hepatitis are typically associated with smaller elevations of transaminases, in the 100-300 U/L range.
True
Elevated ALT and AST with an AST/ALT ratio >2:1 is classically associated with what?
Alcoholic hepatitis
Elevated ______ can be seen in both liver and bone disease, whereas a concomitant elevation of ______ and _______ is consistent with cholestatic liver disease.
ALP
ALP
GGT
While GGT, AST, ALT, and ALP indicate damage to the hepatocytes, _______ and _______ _______ are more reflective of the functional status of the liver.
PT (prothrombin time)
Albumin
***This is because both albumin and clotting factors are produced by hepatocytes!
Factor VII has a serum-half life of about 4 hours, making the PT a good assessment of a (ACUTE/CHRONIC) change in liver function, whereas albumin is more accurate at assessing a (ACUTE/CHRONIC) change in liver function.
Acute
Chronic
Assessment of what globulin is useful for determining an acute vs. chronic pathologic liver process?
IgG – if normal it is acute, if elevated it is chronic
For this disease, the liver function pattern shows elevated transaminase levels and variable increases in other enzymes.
Acute Hepatitis
For this disease, the liver function pattern shows decreased albumin, elevated IgG (with Beta-Gamma bridging on serum electrophoresis) and elevated PT.
Cirrhosis
For this disease, the liver function pattern shows a combination of changes seen in acute hepatitis and cirrhosis patterns.
Chronic Hepatitis
For this disease, the liver function pattern shows an elevated ALP and bilirubin.
Cholestasis (Obstructive Liver Disease)
In hepatocyte _________, fluid flows into the cell causing it to swell and rupture when osmotic regulation is interrupted. Blebs also form carrying off intracellular debris to extracellular. Macrophages will cluster at these sites of injury.
Necrosis
Hepatocyte necrosis is predominant mode of death in what type of injury?
Ischemic/Hypoxic injury
Hepatocyte necrosis is a significant part of the response to _______ _______.
Oxidative stress
Hepatocyte ________ includes cell shrinkage, nuclear chromatin condensation (pyknosis), fragmentation (karyorrhexis), and cellular fragmentation into apoptotic bodies.
Apoptosis
What is the term for apoptotic hepatocytes, so named due to their deeply eosinophilic stain?
Acidophil bodies
This is the term for apoptotic hepatocytes in yellow fever.
Councilman bodies
This type of liver necrosis involves widespread parenchymal loss, and zonal loss of hepatocytes. It may begin as a zone of hepatocyte dropout around the central vein. It produces a space filled with cellular debris, macrophage, and revenants of reticular meshwork. Seen in acute toxic injury, ischemic injuries or viral/autoimmune hepatitis. Also called coagulative necrosis!
Confluent necrosis
This type of liver necrosis occurs when vascular insult leads to parenchymal extinction due to large areas of contiguous hepatocyte death, because zone links central veins to portal tracts. There is a collapse of supporting framework that can occur and cirrhosis may result.
Bridging necrosis
Hepatocytes are almost stem-cell like in their ability to continue to replicate even in the setting of years of chronic injury, therefore stem cell replenishment is not a significant part of _________ repair.
Parenchymal
The principal cell type involved in scar deposition is the…
Hepatic stellate cell
In its quiescent form, hepatic stellate cells are a lipid _______ storing cell. However, in several forms of acute and chronic injury, the stellate cells can become activated and are converted into highly fibrogenic _________.
Vitamin A
Myofibroblasts
Regeneration of the liver occurs by what two major mechanisms?
1) Proliferation of remaining hepatocytes
2) Repopulation from progenitor cells (canals of Hering)
What is the primary intrahepatic stem cell niche?
Canals of Hering
***Severe forms of acute liver failure can activate this!
The stimuli for hepatic stellate cell activation are varied and include…
1) Inflammatory cytokines such as TNF-a, produced by Kupffer cells, macrophages, and other cell types
2) Altered interactions with ECM
3) Toxins and ROS
It is important to remember that hepatic stellate cell activation and scar deposition is reversible if what happens?
The injurious agent is eliminated!
Areas of hepatocyte loss in chronic liver disease, perhaps related to vascular compromise, are transformed into dense _______ _______ through collapse of the underlying reticulin framework and deposition of collagen by myofibroblasts (stellate cells).
Fibrous Septa
_______ fibroblasts may also play a role in the scarring that accompanies chronic liver injury in some disorders. Eventually, the fibrous septa encircle surviving hepatocytes and give rise to diffuse scarring (cirrhosis).
Portal
In chronic liver disease, surviving hepatocytes replicate in an effort to restore the parenchyma, forming regenerative _________ that are a predominant feature in most cirrhotic livers.
Nodules
The most severe form of liver disease is…
Liver failure
Liver failure can be acute, due to sudden and massive hepatic destruction, or chronic, following years of insidious progressive liver injury. Which type of liver failure is more common?
Chronic liver failure
What percentage of functional capacity is lost before hepatic failure appears?
80-90%
When the liver can no longer maintain homeostasis, what offers the best hope for survival?
Liver transplant
In liver failure, without a liver transplant, the mortality rate is what percentage?
80%
For acute liver failure (ALF), it is associated with __________ and _________ that occurs within 26 weeks (6 months) of the initial liver injury in the absence of pre-existing liver disease. Within this window, knowing the interval between onset of symptoms and liver failure may provide helpful clues to the etiology.
Encephalopathy
Coagulopathy
In the US, 50% of ALF is due to what?
Acetaminophen
***Autoimmune hepatitis, other drugs/toxins, and acute HAV and HBV account for most remaining cases!
What is the mnemonic for causes of ALF?
A = Acetaminophen, HAV, Autoimmune hepatitis
B = HBV
C = HCV, Cryptogenic
D = Drugs/toxins, HDV
E = HEV, esoteric causes (Wilson disease, Budd-Chiari)
F = Fatty change of the microvesicular type (fatty liver of pregnancy, valproate, tetracycline, Reye syndrome)
Rarely, ALF is associated with widespread dysfunction of liver cells without obvious cell death, such as in ________ _______ _______ related to fatty liver of pregnancy or in idiosyncratic reactions to toxins (ie, valproate, tetracycline). In these settings, hepatocyte metabolism is severely affected, usually due to __________ dysfunction, preventing the liver from carrying out its normal functions.
Diffuse microvesicular steatosis
Mitochondrial
In states of immunodeficiency, such as untreated HIV, post-transplant immunosuppression, and certain lymphoid malignancies, there are some nonhepatotropic viruses that can cause ALF. What are these viruses?
CMV
HSV
Adenovirus
How will a patient present clinically with ALF?
N/V
Jaundice
Pruritus
Elevated LFTs
These progress to life-threatening coagulation abnormalities and hepatic encephalopathy.
Why are there life-threatening coagulation abnormalities with ALF?
Because the hepatocytes are involved in the synthesis of most blood coagulation factors, such as fibrinogen, prothrombin (II), Factor V, VII, IX, X, XI, XII, protein C and S, and antithrombin.
***Liver sinusoidal endothelial cells produce Factor VIII and von Willebrand factor!
***Impaired clotting due to lack of production of Vitamin K-dependent factors – II, VII, XI, X (“1972”)
What is major sign of hepatic encephalopathy in ALF (due to increased ammonia)?
Asterixis (hand flapping)
If ALF is not recognized or treated, what happens?
Leads to multi-organ failure and death
What are the sequelae of ALF?
– Jaundice and icterus
– Cholestasis = systemic retention of not only bilirubin but other solutes eliminated in bile, can increase risk of life-threatening bacterial infections
– Hepatic encephalopathy
– Coagulopathy
– Disseminated Intravascular Coagulation = liver is responsible for removing activated coagulation factors from the circulation
– Portal HTN = intrahepatic obstruction most likely; leads to ascites and hepatic encephalopathy
– Hepatorenal Syndrome = form of renal failure in individuals with liver failure in whom their kidneys are morphologically and functionally normal
Chronic liver failure is most often associated with _________, which is just a response to the injury NOT a specific diagnosis.
Cirrhosis
Chronic liver failure is the 12th most common cause of mortality in the US. The leading causes of it include…
Chronic HBV
Chronic HCV
NAFLD (Nonalcoholic Fatty Liver Disease)
Alcoholic Liver Disease
This is a classification system used to monitor the decline of patients on the path to chronic liver failure. Class A has the fewest points and is well compensated, Class B is partially decompensated, and Class is decompensated. More points is not good!
Child-Turcotte-Pugh classification
In chronic liver failure, what percentage are asymptomatic until it has reached advanced stages?
40%
Symptoms of Chronic liver failure include the symptoms of ALF plus what?
Portal HTN
What are characteristic symptoms of Chronic liver failure?
- Palmar erythema
- Spider angiomata
- Hypogonadism
- Gynecomastia
Also includes same symptoms as ALF =
- N/V
- Jaundice
- Abnormal LFTs
- Pruritus
- Hepatic encephalopathy (asterixis)
- Coagulation abnormalities
Cirrhosis causes ________ in 85% of cases. 500 ml has to present for it to be clinically detectable. It presents with a fluid wave and shifting dullness.
Ascites
***Think Portal HTN!
What are the principle sites of shunts due to Portal HTN?
Veins around and within the –
- Rectum (hemorrhoids)
- Esophagogastric junction (varices)
- Retroperitoneum
- Falciform ligament of liver (involving periumbilical and abdominal wall collaterals)
For Portal HTN, long-standing congestion may cause congestive _________. The degree of the enlargement varies widely and may reach as much as 1000 gm, but is not necessarily correlated with other features of portal HTN.
Splenomegaly
The massive splenomegaly in portal HTN may secondarily induce _________, which can lead to hematologic abnormalities such as thrombocytopenia and pancytopenia.
Hypersplenism
Increased resistance to portal blood flow (portal HTN) may develop in a variety of circumstances, which can be divided into…
Prehepatic
Intrahepatic
Posthepatic
What are prehepatic causes of portal HTN?
– Obstructive thrombosis of Portal V.
– Structural abnormalities (ie, narrowing) of Portal V. before it ramifies in the liver
What are intrahepatic causes of portal HTN?
- Cirrhosis (most common cause of portal HTN)
- Schistosomiasis
- PBC
- Massive fatty change
- Malignancy
- Amyloidosis
etc..
What are extra-hepatic causes of portal HTN?
- Severe right-sided heart failure
- Constrictive pericarditis
- Hepatic vein outflow obstruction
What are the 4 major clinical consequences of Portal HTN?
- Ascites
- Portosystemic shunt formation
- Congestive splenomegaly
- Hepatic encephalopathy
What are the serious and sometimes fatal sequelae of liver failure?
- Coagulopathy
- Encephalopathy
- Portal HTN
- Bleeding esophageal varices
- Hepatorenal syndrome
- Portopulmonary HTN
This type of viral hepatitis is usually benign and self-limited. It does NOT cause chronic hepatitis or lead to a carrier state, and only uncommonly causes ALF (0.1 to 0.3% of patients).
HAV
What are the viral characteristics of HAV and how is it spread?
ssRNA
Spread fecal-oral via contaminated water (commonly acquired by travelers)
HAV is endemic in countries with poor hygiene and sanitation. In high income countries, the prevalence of seropositivity (indicative of previous exposure) increases gradually with what?
Age – reaches 50% by 50 yo in US
What viral hepatitis can be contracted in high income countries by the consumption of raw or steamed shellfish, which concentrate the virus from seawater contaminated with human sewage?
HAV
T/F. Sexual transmission and materna-fetal transmission is common for HAV.
False. Sexual transmission may occur (not common) but maternal-fetal does NOT.
Do we screen donated blood for HAV?
No
HAV infected individuals have nonspecific symptoms such as fatigue and loss of appetite, and often jaundice. Most recover within 3 months, and disease resolution occurs in nearly all patients by 6 months. ALF occurs in 0.1-0.3% of patients, especially those with _______ _______ _______ due to another etiology.
Chronic liver disease
Other uncommon complications of HAV include prolonged ________ and relapse of disease within 6 months of original onset.
Cholestasis
What extra-hepatic manifestations of HAV?
– Rash
– Arthralgia
– Immune complex mediated complications (ie, leukocytoclastic vasculitis, glomerulonephritis, and cryoglobulinemia).
Is there an effective vaccination for HAV?
Yes
This Ab is present for active HAV and signifies infection.
IgM
This Ab is protective for HAV, and its presence indicated prior infection or immunization.
IgG
HBV infection has varied clinical outcomes, which depends on the age of exposure, comorbid conditions (including exposure to other infectious agents), and host immunity. The major clinical presentations include…
1) Acute hepatitis followed by recovery and clearance of the virus
2) ALF with massive liver necrosis
3) Chronic hepatitis with or without progression to cirrhosis
4) Asymptomatic, “healthy” carrier state