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What are the four functions of the liver?
- 1) Metabolism
- 2) Storage
- 3) Detoxification
- 4) Digestion
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What are three types of cells in the liver?
- 1) Hepatocytes
- 2) Kupffer cells
- 3) Biliary epithelium
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What is the purpose of hepatocytes?
Metabolic functions
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What is the purpose of biliary epithelium?
Allows for exchange of nutrients and hepatocyte product exchange
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What is the purpose of Kupffer cells?
Phagocytosis
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How many portal triads are around each central vein?
6
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What does the liver metabolize?
- Carbohydrates - glucose -> glycogen -> glucose
- Fats - absorbed from intestines -> lipoproteins
- Proteins - Albumin, fibrogen, prothrombin, etc
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What does the liver store?
- Vitamins A, D, B12
- Glycogen
- Fats
- Amino Acids
- Iron
- Poisons/Drugs unable to be broken down
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What is ALT?
- Alanine aminotransferase
- Enzyme produced by liver
- AKA SGPT
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When is ALT elavated?
- Hepatocellular disease and obstructive jaundice
- All forms of hepatitis
- chock and drug toxicity (cell death)
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What is AST?
- Aspertate aminotransferase
- Produced by liver, muscle, and other tissues with high metabolic rates
- AKA SGOT
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When is AST elavated?
- Hepatocellular disease
- Significantly incresed with cirrhosis and acute hepatitis
- Fatty changes, mets, injury
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What causes AST elavation not associated with the liver?
- Mononucleosis
- Myocardial infarction
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What is ALP?
- Alkaline phosphatase
- Enzyme in the cells lining the biliary ducts
- Also present in bone, kidneys, intestines and placenta
- Most sensetive indicator of obstruction
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When is ALP elvated?
- Diseases of bile ducts (Obstruction, Sclerosing cholangitis, Biliary cirrhosis) - Severe
- Hepatocellular disease (Abscesses, Carcinoma, Cirrhosis) - Mild to Moderate
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When is Conjugated/Direct Bilirubin increased?
Obstruction
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When is Unconjugated/Indirect Bilirubin increased?
- Hemolytic diseases
- Trauma (Hematoma)
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When is Total Bilirubin increased?
- Mets
- Lymphoma
- Cholestasis secondary to drugs
- Cirrhosis
- Hepatitis
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What is LDH?
- Lactic Dehydrogenase
- Produced in liver, skeletal muscle, kidneys, etc
- Primarily used to detect pulmonary and myocardial infarctions
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When is LDH elavated?
- May increase with chronic hepatocellular disease or obstructive jaundice
- Moderate increase with Mono
- Mainly used to detect myocardial and pulmonary infarctions
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What is Albumin?
- Transport protein synthesized by the liver
- Helps maintain oncotic pressure
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When is Albumin decreased?
Hepatocellular disease (Decreased protein synthesis)
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What is PT?
- Prothrombin time
- Clotting factor affected by level of vitamin K
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When is PT shortened?
- Extrahepatic obstruction
- GB carcinoma
- Cholecystitis
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What is AFP?
- Alpha fetoprotein
- Produced in fetal liver
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What should be assesed during liver scan?
- 1) Size
- 2) Texture
- 3) Ligaments/Fissures
- 4) Vasculature
- 5) Attenuation
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What is Diffuse liver disease?
- Affects hepatocytes
- Includes fatty changes, cirrhosis, hepatitis,
- Evaluated through LFTs
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What is fatty infiltration?
- Accumulation of lipids in hepatocytes
- Results in cell injury and impaired fat metabolism
- Often asymptomatic
- Can be reversible
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What does fatty infiltration look like on u/s?
- Hyperechoic (fat in cells)
- Hepatomegaly over time
- Increased attenuation (difficult to see posterior)
- Focal Fatty Infiltration: Non-uniform
- Focal Sparing: Hyperechoic w/hypoechoic sparing, usually in medial left lobe anterior to PH
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What is Hepatitis?
- Inflammation of the liver
- A - fecal route
- B - blood
- C - non A, non B
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What are characteristics of acute hepatitis?
- Recovery within 4 months
- Flu-like GI symptoms
- Elavated AST and Total Bilirubin
- Elavated ALT w/rapid decrease after several days
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What are characteristics of chronic hepatitis?
- Lasts > 6 months
- Fatigue
- Jaundice (Non-obstructive)
- Can progress to cirrhosis or liver failure
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What is the sonographic appearance of acute hepatitis?
- Normal
- Decreased echogenicity
- Increased Portal wall appearance
- Possible hepatomegaly
- GB wall thickening
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What is the sonographic appearance of chronic hepatitis?
- Increased echogenicity (fatty changes and fibrosis)
- Coarse texture
- Decreased PV echogenicity
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What is cirrhosis?
- Scarring - irreversible
- Fibrosis, necrosis and regeneration of parenchyma (disorganized appearance)
- 60-70% caused by alcoholism
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What are characteristics of cirrhosis?
- Elavated AST, ALT, Total Bilirubin
- Ascites
- Portal hypertention
- Splenomegaly
- Jaundice
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What is the sonographic appearance of cirrhosis?
Early - hepatomegaly, fatty infiltration, increased echogenicity, increased attenuation
Late - atrophy of right lobe, caudate enlargement, echogenic coarse texture w/nodules, heterogenous
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What is glycogen storage disease?
- Von Gierke Disease - most common
- Abnormally large amounts of glycogen deposited in liver and kidneys
- Diagnosed w/blood tests
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What is the u/s appearance of glycogen storage disease?
- Hepatomegaly
- Increased echogenicity
- Slightly increased attenuation
- Associated with adenomas and FNH
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What are the characteristics of congenital liver cysts?
- simple
- solitary
- small - 20mm
- asymptomatic
- from defect in bile ducts
- anterior right lobe
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What are the characteristics of polycystic liver?
- associated with PCKD
- autosomal dominant
- multiple, simple cysts <3cm
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What are the characteristics of pyogenic abcess?
- variable, puss filled cysts
- solitary
- irregular, round/ovoid
- dirty shadowing, comet tail, microbublbles
- associated with biliary obstruction and infection
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What are the characteristics of candidiasis?
- fungal infection
- immunocomprimised patients (AIDS, chemo)
- elevated wbc
- ruq pain
- multiple small hypoechoic lesions
- may have target/bull's eye appearance w/echoigenic center
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What are the characteristics of granulomatous disease?
- autosomal recessive
- congenital defect in leukocytes
- children
- recurrant respiratory infections
- Poorly marginated, hypoechoic
- possible post enhancement or calcification w/shadowing
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What are the characteristics of amebic abcesses?
- asymptomatic or GI sypmtoms w/leukocytosis and fever
- non-specific appearance
- hypoechoic, lack of wall echoes, internal echos from debris
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What are the characteristics of echinococcal (hydatid) cysts?
- common in sheep-herding areas
- caused by a tapeworm
- daughter cysts
- "water-lily" sign / cyst within a cyst
- possible calcifications
- septations, honeycomb appearance
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What are characteristics of portal hypertension?
- >10mmHg in portal vein
- PV >13mm
- possible collaterals
- acites
- splenomegaly
- GI bleeding - vomit blood, blood in stool
- Jaundice
- Elavated LFTs
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What is the most common cause of portal hypertension?
cirrhoisis
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What does TIPS stand for?
Transjugular-intrahepatic-portosystemic-shunt
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Portal vein thrombosis is associated with _______ ?
Malignancy
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What are two causes for Budd-Chiari syndrome?
Congenital obstruction or thrombus in IVC or main hepatic veins
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What are characteristics of Budd-Chiari?
- Thrombus in IVC/HVs
- hepatomegaly and splenomegaly
- ascites
- enlarged caudate and eventual atrophy of rt lobe
- portal hypertension
- associated with HCC (invades Hepatics)
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What can a arterial-portal fistula result from?
percutaneous liver biopsy or trauma
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What can cause porto-hepatic venous shunts?
Congenital or related to portal hypertension
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What does an intrahepatic-portosystemic shunt fistula look like on ultrasound?
- complex vascular channels connecting portal vein to hepatic vein or IVC
- bidirectional flow
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What are characteristics of beinign tumors?
- Originates from liver parenchyma or bile duct epithelial
- Slow growing
- Asymptomatic
- Low vascular flow
- Doesn't invade surrounding structures
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What are characteristics of cavernous hemangiomas?
- collection of blood vessels
- solitary, "solid" mass
- <5 cm
- very echogenic
- right lobe along periphery
- Women > Men
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What is the most common benign tumor of the liver?
Cavernous hemangioma
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What are characteristics of adenomas?
- Associated w/birth control and glycogen storage disease
- Hypoechoic mass w/possible hyperechoic center w/bleed
- Pain w/rupture
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What is the second most common benign liver mass?
Focal nodular hyperplasia (FNH)
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What are characteristics of FNH?
- Composed of abnormally arranged liver parenchyma (vascular malformation)
- Asymptomatic
- Women <40 yrs
- Subcapsular area
- Well-defined, hyperechoic to isoechoic mass with depressed center
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What are characteristics of malignant tumors?
- Grow rapidly
- vascular
- invade surrounding structures
- Usually from mets
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What is the most common primary malignant liver tumor?
Hepatocellular carcinoma (HCC)
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What is another name for HCC?
Hepatoma
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What are the 3 main types of malignancies in the liver?
- HCC
- Hepatoblastoma
- Mets from colon, breast or lung
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What is a predisposing factor of HCC in the US?
Cirrhosis
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What are predisposing factors of HCC outside of the US?
Hepatitis B and Aflatoxin exposure
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What are clinical characteristics of HCC?
- Men
- History of cirrhosis or hep B or C
- Palpable mass
- hepatomegaly
- appetite disorder
- fever
- Possible AFP increase (70% of patients)
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What are the three presentations of HCC?
- 1) solitary, massive tumor
- 2) multiple nodules throughout liver
- 3) diffuse infiltrative masses in liver
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What is the ultrasound appearance of HCC?
- Variable
- hypoechoic to hyperechoic
- isoechoic w/hypoechoic halo
- diffuse heterogenous texture invading parenchyma
- Invasion into hepatic veins/IVC
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What lab values are expected with mets?
Increased AFP, ALP, and direct bilirubin
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What are clinical characteristics of mets?
- Jaundice
- Hepatomegaly
- Weight loss
- Increased LFTs (AFP, ALP, DB)
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How does mets appear on u/s?
- Multiple
- Anechoic to hyperechoic
- Complex, target lesions
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What are characteristics of lymphoma?
- Night sweats
- Bone pain
- Fever
- Weight loss
- Fatigue
- Abdominal mass
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How does lymphoma appear on u/s?
- enlarged lymph nodes around aorta (cluster of grapes)
- variable appearance of lesions depending on type of lymphoma
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What are characteristics of hepatoblastomas?
- Most common liver malignancy in children
- Precocious puberty
- Palpable mass
- Elavated AFP
- Heterogenous, hyperechoic or cystic w/internal septations
- Occasionally calcify
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What are the two most common reasons for liver transplants?
- Cirrhosis
- Sclerosing Cholangitis
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