The Liver PDF

The Liver Anatomy of the Liver Largest solid organ in the body Weighs 1600g in males and 1400g in females Covered by Glisson capsule 3 Lobes Left, right and caudate Ligaments, fissures and spaces Vascular Hepatic arteries, hepatic veins and portal veins Biliary Tract* Lo...

The Liver Anatomy of the Liver Largest solid organ in the body Weighs 1600g in males and 1400g in females Covered by Glisson capsule 3 Lobes Left, right and caudate Ligaments, fissures and spaces Vascular Hepatic arteries, hepatic veins and portal veins Biliary Tract* Lobes of the Liver Left lobe Divided into medial and lateral segments by the left hepatic vein and ligamentum teres Separated from the caudate lobe by the ligamentum venosum Separated from the right lobe by the middle hepatic vein superiorly and the main lobar fissure inferiorly Right lobe Divided into anterior and posterior segments by the right hepatic vein 6x’s larger than the left lobe Three posterior fossae Gallbladder, porta hepatis, and IVC Caudate lobe Smallest lobe of the liver Separated from the left lobe by the ligamentum venosum Ligaments of the Liver The liver is attached to the diaphragm, anterior abdominal wall, stomach and retroperitoneum by ligaments Coronary ligament Upper and lower layer Connects the liver to the body wall Falciform ligament Connects the liver to the anterior abdominal wall Extends from the diaphragm to the umbilics Separates the right and left subphrenic spaces Gastrohepatic Ligament Attaches the lesser curvature of the stomach to the liver Hepatoduodenal Connects the liver to the proximal doudenum Ligaments of the Liver (cont.) Ligamentum Teres (round ligament) Lies within the falciform ligament Previous fetal umbilical vein Triangular ligament The most lateral portion of the coronary ligament Connects the liver to the body wall Ligamentum Venosum Separates the left lobe from the caudate lobe Obliterated ductus venosum (fetal life) Lesser omentum attaches to the ligamentum venosum Fissures of the Liver Main lobar fissure separates the right lobe from the left lobe of the liver. passes through the gallbladder fossa to the inferior vena cava Right intersegmental fissure Divides the right lobe of the liver into anterior and posterior segments Left intersegmental fissure divides the left lobe into medial and lateral segments. Liver Spaces Morison pouch (Hepatorenal pouch) Lateral to the right lobe of the liver Anterior to the right kidney Communicates with the right paracolic space Subhepatic space Inferior edge of the right lobe Anterior to the right kidney Subphrenic space Between the superior boarder of the liver and diaphragm Anatomy of the Liver Anatomy of the Liver Liver Segments Segment I Caudate lobe Segments II and III Left superior and inferior lateral segments Segments IVa and IVb Medial segments of the left lobe Segments V and VI Caudal to the transverse plane Segments VII and VIII: Cephalad to the transverse plane Liver Segments Sagittal Transverse  Segments of the Liver The right hepatic vein courses within the right intersegmental fissure dividing the right lobe into: anterior and posterior segments The middle hepatic vein courses within the main lobar fissure to separate the anterior segment of the right lobe from the medial segment of the left lobe The left hepatic vein forms the boundary of the cranial third the ascending branch of the left portal vein represents the middle third fissure for the ligamentum teres forms the most caudal division of the left lobe The major branches of the portal veins run centrally within the segments (intrasegmental) EXCEPT the ascending portion of the left portal vein, which runs in the left intersegmental fissure. Ligaments and Fissures Appearance echogenic or hyperechoic presence of collagen and fat within and around the structures Glisson capsule Main lobar fissure Falciform ligament Ligamentum teres (round ligament) Ligamentum venosum Ligaments and Fissures Ligaments and Fissures Vascular Supply Hepatic venous system Portal veins carry blood from the bowel to the liver hepatic veins drain the blood from the liver to inferior vena cava (IVC) Hepatic arteries carry oxygenated blood to liver Bile ducts transport bile to the duodenum. Hepatic Veins Right middle and left hepatic veins course interlobar and drain directly into the IVC Minimum amount of collagen in the walls Straight and longitudinal course Increase in size closer to the diaphragm Hepatic Veins Transverse Long Hepatic Veins The hepatic vein velocity waveform reflects the hemodynamics of the right atrium. This triphasic pattern has two large antegrade diastolic and systolic waves and a small retrograde wave that corresponds to the atrial kick (from the heart) Hepatic Arteries Proper hepatic artery enters the liver at the porta hepatis divides into the Right, middle and left hepatic arteries 30% of the blood supply comes through the hepatic artery  Portal venous system Main, right, and left portal veins Main portal vein enters at the porta hepatis Bifurcates into the right and left 70% of the livers blood supply Nutrient rich blood from the digestive track Walls contain Fibrin Normal diameter right kidney;10mm Abnormal flow in the portal vein Hepatofugal, pulsatile and decreased velocity Porta systemic collaterals Higher resistive index in hepatic artery >.8 Portal Venous Hypertension Hemodynamically significant when portal venous pressure is >10 mm Hg or the hepatic venous gradient >5 mm Hg Collateral circulation develops when the normal venous channels become obstructed gastric veins (coronary veins), esophageal veins, recanalized umbilical vein or splenorenal, gastrorenal, retroperitoneal, hemorrhoidal, or intestinal veins. Portal Venous Hypertension Portal Vein Thrombosis portal hypertension caused by tumor or thrombosis of the portal vein Ascites Splenomegaly and bleeding varices Secondary causes trauma, sepsis, cirrhosis, or hepatocellular carcinoma. Transjugular Intrahepatic Portosystemic Shunt (TIPS) Stent graft is placed between a hepatic vein and portal vein to alleviate symptoms from portal hypertension Effectively bypassing the liver Portal venous flow is re-routed to the IVC via the hepatic vein Usually right portal vein to right hepatic vein Liver Inflammation/ infection Abscesses Candidiasis Echinococcal cyst Hepatitis Schistosomiasis Liver Abscesses Ambeic, fungal and pyogenic Fever, chills, hepatomegaly, elevated Alk Phos, jaundice, abdominal pain Recent travel abroad Ambeic Complex mass Right lobe 80% injesting contaminated water or food Liver Abscesses Pyogenic “pus forming” Sources of infection include cholangitis; portal pyemia secondary to appendicitis, diverticulitis, inflammatory disease, or colitis direct spread from another organ or trauma with direct contamination infarction after embolization or from sickle cell anemia Candidiasis Fungal infection caused by the Candida species Occurs in immunocompromised hosts Undergoing chemotherapy, organ transplant, or infected with HIV The candidal fungus invades the bloodstream and may affect any organ most commonly kidneys, brain, and heart Multiple small hypoechoic masses with echogenic central cores “Wheel with a wheel” or “bullseye” appearance Echinococcal cyst Parasitic tapeworm History of traveling to underdeveloped countries Two different appearances Septated cystic mass Collapsed cyst within a cyst “Water lily” sign Patients present with RUQ pain, leukocytosis, fever, hepatomegaly Hepatitis Hepatitis is the general name for inflammatory and infectious disease of the liver Types A, B and C Symptoms include fever, fatigue, pain in the upper right area of your abdomen, joint pain, nausea or vomiting, diarrhea (hepatitis A), loss of appetite, jaundice, dark urine, pale/clay-colored stool Hepatitis Hepatitis A Uncommon in US spread by fecal contamination fecal-oral route through an infective person’s stool Acute infection Vaccine available if given within 2 weeks of exposure Hepatitis B Spread through blood and other bodily fluids/contaminated needles Vaccine given to children in infancy ~800k people in the us living with chronic hep B (2016) Treatment with antiviral drugs Hepatitis C Spread through blood and other bodily fluids/contaminated needles 2.4 M people living with chronic Hep C (2016) Treatment with antiviral drugs Acute Hepatitis: Ultrasound Liver texture appears normal Prominent portal vein borders Increased echogenicity of liver parenchyma Hepatomegaly Splenomegaly Echogenic portal vein boarders=“starry sky” sign liver parenchyma is more echogenic Chronic Hepatitis: Ultrasound Hepatic inflammation extends >6months Chronic active hepatitis can progress to cirrhosis and liver failure Liver parenchyma becomes coarse with decreased brightness of the portal triads No hepatomegaly Fibrosis present produces “soft shadowing” posteriorly Schistosomiasis Parasite that first travels to the lungs then liver Increase echogensity of the portal walls Atrophy of the right and left lobes Thickened gallbladder walls Portosystemic collaterals Benign Hepatic Conditions Fatty infiltration Cirrhosis Focal nodular hypoplasia Adenoma Cavernous hemangioma Glycogen storage disease Hemochromatosis Fatty Infiltration Fatty liver is an acquired disorder leading to accumulation of triglycerides (lipids) within the hepatocytes reversible Risk factors include: Obesity Alcohol abuse Hyperlipidemia Diabetes Hepatitis Metabolic disorder Ulcerative colitis Fatty Infiltration: Ultrasound Grade I Mild: Minimal diffuse increase in hepatic echogenicity with normal visualization of the diaphragm and intrahepatic vascular borders Grade II Moderate: Increased echogenicity with slightly impaired visualization of the diaphragm and intrahepatic vascular borders Grade III Severe: Significant increase in echogenicity of the liver parenchyma, decreased penetration of the posterior segment of the right lobe of the liver and poor visualization of the diaphragm and hepatic vessels Cirrhosis Chronic degenerative disease that results in the disorganization of lobular architecture of the liver Lobes are covered with fibrous tissue Parenchyma degenerates and becomes necrotic Lobules are infiltrated with fat Most commonly caused by alcoholism Biliary obstruction, hepatitis, Budd-Chaiari syndrome, deficiency in nutrients, cardiac disease Symptoms include Weakness/fatigue, weight loss, abdominal pain, ascites, elevated LFT’s, jaundice Progression will include symptoms of portal hypertension  Macronodular cirrhosis Cirrhosis Micronodular cirrhosis; nodules are small with uniform size Alcoholic cirrhosis with high fat content Biliary cirrhosis; liver is nodule Cirrhosis: Ultrasound  Progression of Doppler Signals: Cirrhosis MPV MHV HA Adenoma Tumor of the glandular epithelium Found more common in women Also related to oral contraceptive use Symptoms Asymptomatic or right upper quadrant pain Increased incidence in patients with type I glycogen storage disease or von Gierke disease The echogenicity of a hepatic adenoma may be hyperechoic, hypoechoic, isoechoic, or mixed usually hyperechoic with a central hypoechoic area caused by hemorrhage Focal Nodular Hyperplasia Second most common benign liver mass (after hemangioma). Found in women