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