Textbook of Diagnostic Sonography Ch. 9 Liver

Mild Fatty Infiltration

Minimal diffuse increase in hepatic echogenicity with normal visualization of the diaphragm and intrahepatic vascular borders

what causes intrahepatic portal hypertension?

Cirrhosis is the most common cause.

Sonographic Findings of Chronic Hepatitis

Course parenchyma No change in liver size Increased echogenicity Decreased brightness of portal triad Fibrosis may produce soft shadowing posteriorly

Hepatitis C

Diagnosed by presence in blood of antibody to HCV (anti-HCV).

Other causes for portal hypertension?

Diffuse metastatic liver disease, thrombotic diseases of IVC and hepatic veins, constrictive pericarditis or other right-sided heart failure over time will cause centrilobular fibrosis, hepatic regeneration, and cirrhosis, all leading to portal hypertension May also develop when hepatopetal flow (toward the liver) is impeded by thrombus or tumor invasion

Why can viral hepatitis be fatal?

Due to secondary acute hepatic necrosis or Chronic hepatitis, which may lead to portal hypertension, cirrhosis, and hepatocellular carcinoma

Causes of fatty liver?

Obesity Excessive alcohol intake Poorly controlled hyperlipidemia Diabetes Excess corticosteroids Pregnancy Total parenteral hyperalimentation Severe hepatitis Glycogen storage disease Cystic fibrosis Pharmaceutical

Extensive hepatic vein occlusion that can occur with this condition is usually fatal within weeks or months at the onset of symptoms

budd chiari syndrome

Hepatic enzyme levels are elevated with?

cell necrosis

Micronodular cirrhosis is most commonly the result of

chronic alcohol abuse

Cirrhosis

chronic and progressive degenerative disease of the liver in which hepatic lobes are covered with fibrous tissue, parenchyma degenerates, and lobules are infiltrated with fat

What disease process shows surface nodularity of the liver edge, especially if ascites is present?

chronic cirrhosis

Macronodular cirrhosis is caused by

chronic viral hepatitis or other infection

In portal hypertension, the most common mechanism for increased resistance to flow occurs in patients with

cirrhosis

Sonographic findings of hemochromatosis

cirrhotic changes hepatomegaly some increased echogenicity seen uniformly throughout parenchyma

Primary Budd-Chiari syndrome

congenital obstruction of hepatic veins or IVC by membranous webs across upper vena cava at or just above entrance of left and middle hepatic veins.

focal subcapsular fat may be found in these patients

diabetics receiving insulin in peritoneal dialysate

name a diffuse hepatocellular disease that is a benign process that may be reversible with correction of the process?

fatty infiltration

sub categories of diffuse parenchymal disease?

fatty infiltration acute and chronic hepatitis early alcoholic liver disease acute and chronic cirrhosis

If the liver appears more hyperechoic than the pancreas?

fatty infiltration should be considered

Patients with hepatitis may initially present with

flu like and gastrointestinal symptoms including loss of appetite, nausea, vomiting, and fatigue

hepatitis

general name for inflammatory and infectious disease of the liver, of which there are many causes May result from local infection (viral hep.), from infection elsewhere in the body (mono or amebiasis), or from chemical or drug toxicity

what portal vein diameter has been associated with portal hypertension?

greater than 13 mm

portal hypertension may develop along two pathways. One entails increased resistance to flow. The other entails...

increased portal blood flow

Transjugular intrahepatic portosystemic shunt (TIPS)

intrahepatic shunts created percutaneously with use of metallic expandable stents *not permanent*

Fatty infiltration is usually asymptomatic but when there are symptoms what are they?

jaundice nausea vomiting abdominal tenderness/pain

Fatty infiltration is not always uniform. It is not uncommon to see patchy distribution of hypoechoic masses (fat) within a dense, fatty infiltrated liver, especially in the ___ lobe.

left

chronic cirrhosis may progress to

liver failure and portal hypertension

fatty infiltration results from?

major injury to the liver or a systemic disorder leading to impaired or excessive metabolism of fat

3 grades of liver texture defined in sonography for classification of fatty infiltration

mild moderate severe

symptoms of chronic hepatitis

nausea anorexia weight loss Tremors Jaundice dark urine Fatigue varicosities.

chronic cirrhosis presentation

neausea, anorexia, weight loss, jaundice, dark urine, fatigue, or varicosities

collateral circulation develops when?

normal venous channels become obstructed. the diverted flow causes embryologic channesl to reopen; blood flows hepatofugally (away from liver) and is diverted into collateral vessels

Mild inflammation from hepatitis impairs hepatocyte function, whereas more severe inflammation and necrosis may lead to

obstruction of blood and bile flow int he liver and impaired liver cell function

What is a hepatocyte?

parenchymal liver cell that performs all the functions ascribed to the liver.

fatty liver is so dense that it results in?

portal vein structures difficult to visualize because of increased attenuation typical gain settings do not allow penetration to posterior border, so it is more difficult to see the outline of the portal vein and hepatic vein borders the increase in echo texture may result from increased collagen content of the liver or increase in lipid accumulation

chronic active hepatitis

progresses to cirrhosis and liver failure.

viral hepatitis

results from infection by a group of viruses that specifically target the hepatocytes (local infection)

If portal hypertension becomes extensive, the portal system can be decompressed by

shunting blood to the system venous system via portacaval shunts

fatty infiltration of the liver is the precursor for?

significant chronic disease in some patients

What causes extrahepatic portal hypertension?

the development of increased pressure in the portal-splenic venous system

sonographic comparison of the liver parenchyma to these organs are useful in determining if fatty infiltration is present

the kidney the pancreas - its parenchyma is more echogenic than the liver

Secondary Budd-Chiari Syndrome

thrombosis in hepatic veins or IVC occurs in patients with predisposing conditions: *prolonged oral contraceptive use, *pregnancy tumors (hepatocellular carcinoma, renal cell carcinoma, adrenal carcinoma, leiomyosarcoma of the IVC) *infections *trauma

Budd-Chiari syndrome

thrombosis of the hepatic veins or IVC. uncommon, dramatic illness characterized by abdominal pain, massive ascites, and hepatomegaly other symptoms include: jaundice, vomiting, diarrhea may present acutely (rare) or as a chronic illness (common)

fatty infiltration implies?

increased lipid accumulation in the hepatocytes

Intrahepatic or sinusoidal portal hypertension

Hepatic vein pressure is elevated

Presinusoidal portal hypertension

Hepatic vein pressure is normal

portal venous hypertension is associated with?

*Cirrhosis *Thrombosis of hepatic veins, portal veins, and IVC

portal venous ultrasound findings?

*Dilation of portal, splenic and mesenteric veins *Reversal of portal venous blood flow *Development of collaterals

Sonographic Findings with Acute Hepatis

*Texture may be normal or portal vein borders may be more echogenic than usual (Starry Sky sign). *Parenchyma slightly more echogenic. *Attenuation may be present. *Hepatosplenomegaly *Gallbladder wall markedly thickened w/contraction of lumen

Sonographic findings of cirrhosis

*hepatomegaly - first finding (early) *shrunken r. lobe w/enlarged caudate and l. lobe (severe)

Sonographic findings of glycogen storage disease

-Hepatomegaly -Increased echogenicity -Slightly increased attenuation (similar to diffuse fatty infiltration) -adenomas (round, homogeneous (when small), echogenic)

Sonographic findings in portal venous hypertension

-collateral circulation/reversal of flow -ascites -hepatosplenomegaly

characteristics of focal fatty infiltration

-not always uniform -does not displace normal vascular architecture -margins may appear nodular, round, or interdigitated with normal ttissue -has ability to resolve rapidly **focal sparing** suspected in patients with masslike hypoechoic areas in a liver that is otherwise increased in echogenicity.

How many categories of glycogen storage disease? How are they divided?

6. Divided on basis of clinical symptoms and specific enzymatic defects

Portal venous hypertension exists when the portal venous pressure is above ____ or the hepatic venous gradient more than ______.

> 10 mm Hg > 5 mm Hg

Pathologic Anomalies of the Liver?

>Agenesis >Anomalies of position >Accessory fissures >Vascular anomalies

Agenesis

>Agenesis of the liver is incompatible with life. >There have been reported cases of agenesis of the right, left, or caudate lobes. >When this occurs, hypertrophy of the other lobes develops.

Variations in the portal venous anatomy are uncommon but include:

>Atresias- absence or abnormal narrowing >Strictures- An abnormal narrowing of a body passage >obstructing valves

Chronic hepatitis

>Exists when clinical or biochemical evidence of hepatic inflammation extends beyond 6 months. >Causes are viral, metabolic, autoimmune, or drug-induced. >Inflammation extending across the limiting plate, spreading out in a perilobular fashion, and causing piecemeal (one piece at a time) necrosis, which is frequently accompanied by fibrosis.

Accessory fissures

>True accessory fissures are uncommon and caused by infolding of peritoneum. >The inferior accessory hepatic fissure is a true accessory fissure that stretches inferiorly from the right portal vein to the inferior surface of the right lobe of the liver.

Hepatitis B

>caused by the type B virus, which exists in the bloodstream and can be spread by transfusions of infected blood or plasma or through the use of contaminated needles. >greatest risk to health care workers because of the nature of transmission. >This virus is also found in body fluids, such as saliva and semen, and may be spread by sexual contact.

Hepatitis A

>found worldwide and is spread primarily by fecal contamination, because the virus lives in the alimentary tract. >In developing countries, the disease is endemic and the infection occurs very early in life. >acute infection that leads to either complete recovery or death from acute liver failure.

Von Gierke disease (type I)

Abnormally large amounts of glycogen are deposited in the liver and kidneys

portacaval shunt

Attaches the main portal vein at the superior mesenteric vein-splenic vein confluence to the anterior aspect of the inferior vena cava.

mesocaval shunt

Attaches the mid-distal superior mesenteric vein to the inferior vena cava May be difficult to image if overlying bowel gas is present

splenorenal shunt

Attaches the splenic vein to the left renal vein

sonographic findings for Budd chiari syndrome...

Caudate lobe will be enlarged with a small or atrophied right lobe.

Moderate Fatty Infiltration

Increased echogenicity with slightly impaired visualization of the diaphragm and intrahepatic vascular borders

Glycogen Storage Disease

Inherited disease; characterized by abnormal storage and accumulation of glycogen in the tissues, especially the liver and kidneys.

Severe Fatty Infiltration

Significant increase in echogenicity of the liver parenchyma, decreased penetration of the posterior segment of the right lobe of the liver, and decreased to poor visualization of the diaphragm and hepatic vessels

Vascular anomalies

The hepatic artery may have many variations as it arises from the celiac axis. At least 45% of patients may have the following variations: >Replaced left hepatic artery originating from the left gastric artery >Replaced right hepatic artery originating from the superior mesenteric artery >Replaced common hepatic artery originating from the superior mesenteric artery

Anomalies of position

The liver may be found in other locations in two conditions: >situs inversus, in which the organs are reversed, with the liver on the left and spleen on the right >congenital diaphragmatic hernia or omphalocele, where varying amounts of liver tissue may herniate into the thorax or outside the abdominal cavity.

Diffuse Abnormalities of the Liver Parenchyma

biliary obstruction common duct stones and strictures extra hepatic mass passive hepatic congestion

Most common type of glycogen storage disease

Type 1, Von Gierke's disease.

Chronic persistent hepatitis

a benign, self-limiting process.

Hemochromatosis

a rare inherited disease of iron metabolism characterized by excess iron deposits in the body. May lead to cirrhosis and portal hypertension.

Doppler of Budd Chiari

absent, reversed, dampened, or turbulent

What's fatty liver?

acquired, reversible disorder of metabolism, resulting in an accumulation of triglycerides within the hepatocytes

interruption in the flow of bile through any part of the biliary system, from the liver to duodenum (cholestasis) causes

alkaline phosphatase and direct bilirubin levels to increase

what is fatty infiltration of the liver?

an acquired, reversible disorder of metabolism, resulting in intracellular accumulation of triglycerides within hepatocytes

where do collateral veins most frequently occur?

area of the esophagus, stomach, and rectum. rupture of these can cause massive bleeding/death

most characteristic clinical feature of budd-chiari syndrome

ascites

acute cirrhosis presentation

asymptomatic or may have nausea, flatulence, ascites, light-colored stool, weakness, abdominal pain, varicosities, and spider angiomas

Other causes of cirrhosis besides alcohol abuse, chronic viral hepatitis, or other infection

biliary cirrhosis Wilson's disease premary sclerosing cholangitis hemochromatosis

What form of hepatitis is the greatest risk to health care workers?

hepatitis B

Diffuse hepatocellular disease affects?

hepatocytes and interferes with liver function.

Patients with cirrhosis have an increased risk of what kind of tumors?

hepatoma

classic clinical presentation of patient with cirrhosis

hepatomegaly, jaundice, and ascites

why are collateral veins formed?

in an effort to relieve the pressure of portal hypertension, these veins are formed that connect to the systemic veins. known as varicose veins

What is portal hypertension?

increase in portal venous pressure or hepatic venous gradient

How is diffuse disease measured?

through a series of liver function tests

the most common collateral pathways

through the coronary and esophageal veins

why is sonography useful in patients with portal hypertension?

to define presence of ascites, hepatosplenomegaly, and collateral circulation; the cause of jaundice; and the patency of hepatic vascular channels

Portal vein thrombosis may develop secondary to

trauma sepsis cirrhosis hepatoceullar carcinoma

on sonography, fatty infiltration most commonly appears in a diffuse distribution and results in

uniform increased echogenicity of the liver

Acute Hepatitis

without complications, clinical recovery usually occurs within 4 months *complications may include liver cell injury, swelling of the hepatocytes, and hepatocyte degeneration, which may lead to cell necrosis. *retinculoendothelial and lymphocytic response with Kupffer cells enlarging *regeneration