Liver Review
Describe the complications of cirrhosis of the liver.
essential features of cirrhosis are simultaneous parenchymal necrosis, regeneration, and diffuse fibrosis, resulting in disorganization of lobular architecture. The disease process is chronic and progressive, with liver cell failure and portal hypertension as the end stage. Cirrhosis is most commonly the result of chronic alcohol abuse but can be the result of nutritional deprivation, hepatitis, or other infection.
Discuss the sonographic findings of a cirrhotic liver.
findings may show course texture of the liver parenchyma secondary to fibrosis and nodularity. Increased attenuation may be present, with decreased vascular markings. Hepatosplenomegaly may be present, with ascites surrounding the liver. Chronic cirrhosis may show nodularity of the liver surfaces, especially if ascites is present. The hepatic fissures may be accentuated. The isoechoic regenerating nodules may be seen throughout the liver parenchyma. Portal hypertension may be present with or without abnormal Doppler flow patterns. Patients who have cirrhosis have an increased incidence of developing hepatocellular carcinoma within the liver parenchyma
How does the blood leave the liver?
from the hepatic veins into the IVC
What is the name given to the liver cells?
hepatocytes >the are packed in the walls of cells that are separated by blood sinusoids
What is the effect of fatty infiltration on the liver?
increased lipid accumulation in the hepatocytes and is the result of significant injury to the liver or a systemic disorder leading to impaired or excessive metabolism of fat. Fatty infiltration is a benign process and may be reversible
Name the three basic types of abscess formation in the liver.
intrahepatic, subhepatic, and subphrenic
What are the clinical symptoms and sonographic findings of a liver adenoma?
-RUQ pain secondary to rupture, with bleeding into the tumor -increased in patients with Type I glycogen storage disease or von Gierkes disease -on ultrasound, the mass may look similar to focal nodular hyperplasia, it is hyperechoic with central hypoechoic area caused by hemorrhage -lesion may be solitary or multiple, if it ruptures then fluid should be found in the peritoneal cavity
Discuss the three patterns of hepatocellular carcinoma.
-Solitary massive tumor -Multiple nodules through the liver -Diffuse infiltrative masses in the liver -all three patterns cause hepatomegaly
Name the primary sites that cause metastatic disease to spread to the liver.
-colon, breast and lung -majority of metastases arise from a primary colon or from an HCC
What are the clinical and sonographic findings of metastatic liver disease?
-hepatomegaly, abnormal liver function tests, weight loss, and decreased appetite -well-defined hypoechoic mass -well-defined echogenic mass -diffuse distortion of nomal homogenous parenchymal pattern without focal mass -most cases of hypervascular lesioins correspond to hyperechoic patterns
Describe the appearance of lymphoma of the liver.
-hepatomegaly, with normal or diffuse alteration of parenchymal echoes -focal hypoechoic mass may be seen sometimes -presence of splenomegaly or retroperitoneal nodes may help confirm the diagnosis of lymphoma -Hodgkins lymphoma appears with hypoechoic and diffuse ultrasound patterns in the liver -Non-Hodgkins lymphoma may appear with target and echogenic mass lesions
Describe the characteristic findings of an amebic abscess.
-it's a collection of pus formed by disintegrated tissue in a cavity, usually the liver -caused by the protozan parasite -may be asymptomatic or have GI symptoms such as abdominal pain, diarrhea, leukocytosis and low fever -ultrasound appearance is veriable and nonspecific -may be round or oval and may lack defined wall echoes -lesion is hypoechoic compared with normal liver parenchyma and may show low-level echoes at higher sensitivity -distal enhancement may be seen beyond the lesion
What causes biliary obstruction distal to the cystic duct?
-may be caused by stones in common duct, an extrahepatic mass in the porta hepatis
Describe the sonographic findings and incidence of focal nodular hyperplasia.
-may be more than one mass, many located along the subcapsular area of liver, some are pedunculated and many have central scar -on unltrasound, the lesions appear well defined and show hyperechoic to isoechoic patterns as compared to liver -internal linear echoes may be seen within the lesions if multiple nodules are together
Describe the ultrasound appearance of an echinococcal cyst of the liver.
-several patterns may occur, from a simple cyst to a complex mass with acoustic enhacement -shape of cyst may be oval or spherical, and may have regularity of walls -calcifications may occur -septations are very frequent; water lily sign, which shows a detachment and collapse of the germinal layer; or cyst within a cyst. -if a daughter cyst is found, it is specific for echinococcal disease
What is the composition of bile?
97% water, bile salts and pigments, and inorganic salts -formed by hepatocytes
What role does the liver play in the hormonal regulation of blood sugar?
>>has enzymes that convert glycogen to glucose, glycerol to glucose, and vice versa, and amino acids to glucose and the reverse >liver cannot synthesize glucose from fatty acids >through portal vein, liver has direct access to the carbohydrates absorbed from the intestine, which makes it the center for the synthesis, delivery, storage, and production of glucose >liver has a special enzyme to free glucose and is the only organ that can secrete glucose into the blood when the level of this substance exceeds the blood level >liver helps to maintain a steady state of glucose in the bloodstream
Describe the role of amino acids within the liver.
>form a pool that can be used to make the various proteins of the liver and blood as well as glucose, fats, and energy >can be exchanged with a second similar pool in the blood, which in turn exchanges amino acids with a third pool within the tissue cells >liver is a major center for synthesis and degradation of amino acids and proteins
What is the metabolic physiology of carbohydrates in the liver?
>liver converts sugars to glucose >when the blood glucose is low, the liver releases glucose into the blood >when the blood glucose is high, the liver cells take up and store glucose
Discuss the role of fat metabolism in the liver.
>liver is capable of forming, degrading, and storing fats >through fat metabolism, liver can make cholesterol and form ketone bodies
Describe the findings of a cavernous hemangioma.
>typical in that most are hyperechoic with acoustic enhancement >round, oval or lobulated with well-defined borders >larger hemangiomas may have mixed pattern as a result of necrosis, may undergo degeneration and fibrous replacement, and become heterogenous >it may also project with calcifications, which appear complex or anechoic echo patterns
. How does diffuse hepatocellular disease affect the hepatocytes in the liver?
Diffuse hepatocellular disease affects the hepatocytes and interferes with liver function. The hepatocyte is a parenchymal liver cell that performs all the functions ascribed to the liver. A measurement of this abnormality is done through a series of liver function tests. The hepatic enzyme levels are elevated with cell necrosis.
Trace the path of bile after the hepatocytes from bile in the liver.
Hepatocytes form bile and secrete it into small canaliculi, theses form bile ducts. The blue ducts coalesce to form the hepatic duct which emerges from the liver.
Describe the difference between acute and chronic hepatitis.
In acute hepatitis, damage to the liver may range from a mild disease to massive necrosis and liver failure. Hepatosplenomegaly is present, and the gallbladder wall is thickened. Chronic hepatitis exists when there is clinical or biochemical evidence of hepatic inflammation for at least 3 to 6 months. Chronic persistent hepatitis is a benign, self-limiting process. Chronic active hepatitis usually progresses to cirrhosis and liver failure.
Describe the ultrasound appearance of fatty infiltration of the liver
Moderate to severe fatty infiltration shows increased echogenicity on ultrasound examination. Enlargement of the lobe affected by the fatty infiltration is evident. Visualization of the portal vein structures may be difficult because of the increased attenuation of the ultrasound. Thus it becomes more difficult to see the outline of the portal vein and hepatic vein borders.
What does an ultrasound evaluation of the liver parenchyma include?
The evaluation of the liver parenchyma includes the assessment of its size, configuration, homogeneity, and contour examined in a supine, right anterior oblique postion in a transverse, coronal, subcostal oblique, and sagittal view to completely survey the organ.
Describe the clinical findings in a patient with hepatitis.
present initially with flu and gastrointestinal symptoms, including loss of appetite, nausea and vomiting, and fatigue. Jaundice may occur in severe cases. Laboratory values show abnormal liver function tests, with increases in the ALT, AST, and bilirubin.
Name the two sources that supply blood to the liver
The portal vein and hepatic artery
Describe the pathway of the blood as it flows into the liver.
The portal vein brings 70-80% of blood to the liver, and the remaining 20-30% is oxygenated blood through the hepatic artery. The right lobe receives blood primarily from intestines and the left lobe and caudate lobes receive blood from the stomach and the spleen.
What diseases cause an elevation of both direct and indirect bilirubin?
Total bilirubin is the elevation of both direct (conjugated) and indirect (unconjugated) bilirubin levels in hepatic metastasis, hepatitis, lymphoma, cholestasis secondary to drugs, and cirrhosis, but the increase in the direct level is more marked.
Name the common causes of fatty liver.
alcoholic liver disease, diabetes mellitus, obesity, severe hepatitis, chronic illness, and steroids.
What is the definition of a neoplasm?
any new growth of new tissue, either benign (locally and doesn't spread) or malignant (uncontrolled and is prone to metastasize to nearby or distant structures via bloodstream and lymph nodes)
What causes biliary obstruction proximal to the cystic duct?
can be caused by carcinoma of CBD or metastatic tumor invasion of the porta hepatis