Topics B56-64 Liver and Gall Bladder Flashcards
3 categories of patterns of injury that cause liver failure:
- Acute liver failure with massive hepatic necrosis: e.g. drugs, viral hepatitis
- Chronic liver disease: typically cirrhotic liver from alcoholism
- Hepatic dysfunction without overt necrosis: less common. Hepatocytes unable to perform their function, maybe from mitochondrial injury from some drug or toxin-mediated injuries, Reye syndrome
How much of hepatic function must be lost before hepatic failure can occur?
80-90% of hepatic function must be lost (liver has large reserve capacity)
Some clinical features of liver failure (~6 are listed)
- Jaundice: cannot conjugate bilirubin, accumulates first in sclera
- Hypoalbuminemia: cannot produce proteins
- Hyperammonemia: urea cycle impaired
- Spider angiomas, Gynecomastia, Hypogonadism (putting them together because all are related to poor breakdown of estrogens)
- Coagulopathy (reduced production of clotting and anti-clotting factors) - INR and PT are good tests for liver failure
- Poor metabolic control (hypoglycemia typically, also maybe hyperglycemia after eating)
What is the term for accumulation of fat droplets in hepatocytes?
What is the name for apoptotic hepatocytes seen in histology? How do they appear?
Fat droplets: Steatosis
Apoptotic hepatocytes: Councilmann bodies: shrunken hepatocytes, eosinophilic cytoplasm
Some causes of acute liver failure
there are many more than the 6 that are on the card, just trying to remember some examples
- Drugs: most commonly paracetamol / acetaminophen / tylenol.
- Viral infections: Hepatitis A, B, or D. (HCV won’t cause acute but chronic failure) - sometimes cryptogenic viral hepatitis
- Wilson disease (can’t filter copper; deposits in liver)
- Liver metastases
- Leptospira infection (Weil disease)
- Poisoning: e.g. Amanita phalloides
If liver necrosis affects only one zone of the liver, what is it called?
What is the other type of necrosis that is larger, and connects a portal vein to other portal veins or to the central vein?
One zone: Confluent necrosis
Larger, connecting necrosis: Bridging necrosis
What are 2 mechanisms and 3 symptoms/consequences of hepatic encephalopathy?
Mechanisms:
- Hyperammonemia -> ammonia deposits in astroglia, causing osmotic swelling and overproduction of glutamine
- Aromatic amino acids increase, which are converted into false neurotransmitters
Symptoms:
- Altered mental status, somnolence
- Asterixis: flapping tremor, can’t maintain posture
- Coma, death
What must be intact for liver regeneration to occur?
The connective tissue framework, e.g. the basement membrane.
Note that if someone donates part of their liver, hepatocytes will multiply in the removed area but they won’t have the proper structure or vascular supply and so won’t be functional. Ito cells regenerate collagen in damaged liver (role in cirrhosis).
In ischemic liver injury and some drug/toxin injuries, what parts of the liver (which hepatocytes) are most affected?
The hepatocytes around the central vein: most susceptible to hypoxia
2 major functions of bile
- Eliminates bilirubin, excess cholesterol, and insoluble xenobiotics that won’t make it to the urine
- Emulsifying dietary fats for absorption
Definitions of:
Jaundice
Cholestasis
Jaundice: yellowish discoloration of skin and sclera
Cholestasis: systemic retention of not only bilirubin, but the other solutes eliminated in bile (e.g. cholesterol and bile salts)
4 steps of bilirubin processing in the liver
simple version; not like in biochem
- Carrier-mediated uptake of unconjugated bilirubin
- Binding to cytostolic protein, delivery to endoplasmic reticulum
- Conjugation with glucoronic acid by bilirubin UGT
- Excretion of water-soluble, non-toxic, conjugated bilirubin into the bile. (Then goes onto be modified by gut bacteria, either excreted in feces or reabsorbed and put into the urine)
5 genetic causes of jaundice
- Gilbert Syndrome: UGT has low activity. Unconjugated hyperbilirubinemia
- Criggler-Najjar: either total or partial UGT deficit. Unconjugated hyperbilirubinemia
- Dubin Johnson: MRP2 pump defective, cannot expel conjugated bilirubin.
- Rotor: transport of bilirubin into liver is impaired. Conjugated hyperbilirubinemia (doesn’t really make sense to me why it’s not unconjugated but OK)
- Hereditary hemochromatosis: iron overload in liver -> damage, jaundice (probably both conjugated and unconjugated)
What are PSC and PBC in regards to cholestasis?
you get these acronyms in the topic prompt
PSC: Primary Sclerosing Cholangitis. Progressive fibrosis of both extra and intrahepatic bile ducts of all sizes (compare to PBC). Often accompanied by ulcerative colitis. Unknown cause, anti-nuclear cytoplasmic antibodies usually present.
PBC: Primary Biliary Cholangitis. Destruction of only small and medium-sized intrahepatic bile ducts. Antimitochondrial autoantibodies.
2 main types of Cholelithiasis
- Cholesterol stones: crystalline cholesterol monohydrate. High levels of cholesterol exceeds the solubilizing capacity of bile. Usually radioluscent.
- Pigment stones: contain bilirubin. More likely to occur if high levels of unconjugated bilirubin, as in hemolytic anemia or infection of biliary tract. Can be either radioluscent or opaque.
What is the difference between pure, mixed, or combined gall stones?
Pure stones: exclusively cholesterol or bilirubin
Mixed: all components are there in random distribution
Combined: Center of stone is one type (e.g. cholesterol), and it’s surrounded by layers of the other type around it
What is the difference between brown and black pigment stones?
Black pigment stones: sterile. Crumble. Found in gall bladder. Usually radio-opaque.
Brown: result of infected ducts. Soft, greasy. More likely found in intra or extrahepatic ducts. Usually radioluscent.
Which people are at risk for gallstones?
4 F's: -Forty: usually at least 40 y/o -Fat: high cholesterol -Female: relation to estrogen -Fertile: have had children Sometimes also "Fair" - more likely in white people
Also any condition where gallbladder motility is reduced (pregnancy, rapid weight loss, spinal cord injury)
