Liver function
T/F: heavy metals that cannot be metabolized or buffered are converted by the liver into something that can be excreted by the kidneys.
False! These heavy metals cannot be metabolized and are instead just stored in hepatocytes, never to be excreted.
The liver converts excess glucose into what to be stored?
Glycogen. This can later be converted back to glucose pretty quickly if blood sugar levels drop.
Why does “fatty liver” develop?
Hepatic injury causes decreased protein synthesis in the liver. Lipids need proteins in order to be transported into circulation. A decrease in these transport proteins causes lipids to start accumulating in hepatocytes, impairing their function.
Bonus Q: What does steatosis mean?
What can a decreased production of albumin lead to?
Edema
T/F: most liver damage from cirrhosis is reversible if the cause can be identified.
False! Most liver damage from cirrhosis is irreversible. If we can identify and eliminate the cause, we can help prevent further damage, but we can’t reverse it.
What is gluconeogenesis, another function of the liver?
The conversion of nandrolone-carbs (protein and fat) into glucose.
T/F: the conversion of carbs and protein into triglycerides for storage primarily occurs in the liver.
True!
What causes the ‘varices’ seen in liver cirrhosis?
Cirrhosis (hepatocyte scarring) obstructs hepatic blood flow, causing it to back up into the hepatic portal vein. This can cause gastric or esophageal varices (enlarged vessels) to form, which are at risk of rupturing and causing a GI bleed.
T/F: A patient with liver disease will have an increased risk of bleeding.
True!
Bonus Q: why?
T/F: in general, hepatocytes can regenerate injured cells.
True!
Bonus Q: what causes the irreversible loss of hepatocytes?
How can we treat ascites developed because of liver disease?
Diuretic therapy might help a little bit, but paracentesis will help more.
The liver is responsible for synthesizing 90% of the plasma proteins in the blood. What are at least 2 roles of these proteins?
-albumin maintains oncotic pressure in the vasculature
-transporting lipid-soluble molecules in the plasma
-complement proteins in the inflammatory response
-clotting factors essential for the blood coagulation process (Bonus Q: except for which clotting factor?)
What does ammonia need to be converted into to be secreted by the kidneys?
Urea
Bonus Q: what is ammonia a by-product of?
What are two possible causes of non-alcoholic fatty liver disease (NAFLD)?
-obesity
-metabolic syndrome (insulin resistance is a mjor contributing factor to NAFLD)
In liver disease, do levels of ammonia in the blood increase or decrease?
Increase. The liver is no longer able to convert ammonia into urea, meaning the kidney can no longer excrete it. This leads to increased serum ammonia levels.
T/F: Even in the absence of disease, liver function generally declines with age.
False! In the absence of disease, liver function shows little decline with aging.
“It’s a fighter” -Professor Will
What drug can we give to help control serum ammonia levels to slow the progression of hepatic encephalopathy?
Lactulose
What is iron stored as in the liver?
Ferritin
Bonus Q what are these stores used for?
What vitamins are stored in the liver to prevent deficiencies?
Vitamin A, D, and B12
What is hepatic encephalopathy?
A loss of brain function due to liver damage.
Bonus Q: the build up of what by-product can cause hepatic encephalopathy?
How does hepatic injury and disease affect the immune system?
The liver is responsible for producing all of the inflammatory proteins, including those in the complement and kinin systems. Liver disease will cause a decreased production of these proteins, causing significant immunosuppression.
Bonus Q: what does ‘opsonization of bacteria’ mean?
What is the most common cause of liver disease in adults?
Chronic alcohol use
Bonus Q: what is the second more common cause?
What are at least 2 non-pharmacologic management options for ruptured esophageal varices?
-packed RBCs
-platelets
-suction blood out of stomach
-esophageal balloon to apply pressure to the bleeding varices
How does the liver affect bilirubin?
Bilirubin is not water-soluble. In the liver, hepatocytes conjugate bilirubin, increasing its solubility and allowing it to be secreted into bile.
Bonus Q: what is bilirubin a by-product of?
What cells in the liver are responsible for removing old or injured RBCs from circulation?
Kupffer cells phagocytize the RBCs that need to be removed from circulation, as well as foreign organisms such as bacteria.
What is the difference between simple fatty liver (hepatic steatosis) and non-alcoholic steatohepatitis (NASH)?
Simple: fatty infiltrate are present in the liver, but there are no signs of inflammation or scarring
NASH: this is when there are fatty infiltrates AND scarring and fibrosis are present. It will eventually lead to cirrhosis.
Bonus Q: what is a major cause of inflammation in NASH?
How is AST different from ALT?
Both are enzymes produced by the liver and have increased levels in circulation when liver damage occurs.
AST, however, is generally higher when this damage is alcohol-related and can be decreased in pregnancy and with SEVERE liver disease.
What is the role of activated vitamin D?
-absorbing dietary calcium from the intestines
-promotes deposition of calcium in bones
Bonus Q: How is vitamin D activated?
What medications can we use to help manage esophageal varices before they rupture? *Professor Will said to know this*
-vasodilators (nitroglycerin) to vasodilate hepatic vessels and decrease vascular resistance
-beta-blockers (propranolol) to reduce the SNS response
-proton pump inhibitors (omeprazole) to decrease the erosion of the varices
What are at least two of the liver’s primary functions? (5 total listed)
-Metabolic Functions
-Digestive Functions
-Excretory Functions
-Detoxification Functions
-Hematologic Functions
Name at least 4 specific jobs the liver performs.
-stores glucose as glycogen
-gluconeogenesis
-synthesize cholesterol and phospholipids
-synthesizes 90% of plasma proteins
-storing vitamins
-the first step of activating vitamin D
-storing iron as ferritin
-converting ammonia to urea (to be excreted by the kidneys)
-conjugating bilirubin so it can be secreted in bile
-detoxification
-removing bacteria from the bloodstream
-removing old or damaged RBCs from the bloodstream
What is the difference between micronodular and macronodular cirrhosis?
Micronodular: small nodules, thin bands of fibrotic tissue
Macronodular: large, irregular bands of nodules with bands of fibrous tissue
Bonus Q: explain the different causes of each and which has a better prognosis.
What is ALT and why would we see an increase in ALT levels?
ALT: an enzyme produced by hepatocytes (alanine aminotransferase)
ALT can leak into circulation when cells are damaged or die. ALT levels increase because of inflammation or infection in the liver, any condition causing hepatic ischemia (MI, burns, trauma), and some drugs (acetaminophen, aspirin, oral contraceptives).
Bonus Q: what can cause a decrease of ALT levels?
What are at least two etiologies of acute liver injury?
Viral or alcohol hepatitis, malignant infiltration, toxin exposure, sepsis, heat stroke, acetaminophen overdose.
Bonus Q: when is liver failure determined to be acute rather than chronic?
What are 2 vasoconstrictors we might use if an esophageal varices ruptures?
-vasopressin
-octreotide