CH 9 Pediatric Liver and Biliary System Flashcards
Pediatric liver
lies in the RUQ of abdomen and is composed of 3 lobes; right, left and caudate.
normal liver is homogeneous and slightly hyperechoic compared to the normal renal cortex.
Liver sono echogenicity compared to abdominal organs
Renal sinus > pancreas > Spleen/Liver > Renal cortex
liver is iso- or hypoechoic relative to the kidneys in neonates. the liver becomes hyperechoic to the kidneys at the end of the first year of life.
Liver size
In children the right love of the liver extends to or just below the right kidney. the left lobe should extend no farther than slightly left of the Aorta. In young babies the left lobe is relatively large and extends well over the midline.
Hepatic veins
MHV divides the liver into the right and left lobes and runs in the same plane with the IVC and GB fossa.
RHV divides the anterior/posterior segments of the right lobe
LHV divides the medial/lateral segments of the left lobe
INTERsegmental vessels
Hepatic veins. They course between the lobes and the segments of the Liver.
The HV walls are not echogenic.
INTRAsegmental vessels
include the Portal Triad; MPV, proper HEA and CHD.
These course to the center of each segment of the liver.
PV walls are echogenic
Portal veins
RPV: anterior and posterior branch
LPV: medial and lateral branch
normal diameter of the PV:
<10 years old= 8mm
>10 years old= 10 mm
Fetal circulations
umbilical vein > LPV > ductus venosus > MHV/LHV > IVC
Ligamentum Teres
remnant of the umbilical vein. runs from the umbilicus to the LPV. the umbilical vein obliterates after birth to become the ligamentum teres.
runs in the intersegmental fissure along with the falciform ligament.
recannulize with portal HTN and becomes portocystemic collateral.
Ligamentum venosum
remnant of the ductus venosus, runs from the LPV to the IVC, separating the left lobe of the liver from the caudate lobe.
Hepatomegaly causes in children:
neuroblastoma, hepatoblastoma, cardiac failure, fatty infiltration, hepatitis, leukemia, metaabolic liver disorders, angiomatous lesions, mets from neuroblastoma
Hemangiomas
primary, benign vascular neoplasms which consist of multiple vascular channels.
Infants may have skin hemangiomas and be asymptomatic, need a liver ultrasound if > 5
*hypoechoic in children/infants
more common in older children and young adolescents.
if multiple and with hemorrhage or cardiac compromise, steroid therapy may be used.
if solitary, hemangioma matures and vessel growth slows. vessels may enlarge and form “lakes” (cavernous hemangiomas) rarely seen in children.
Infantile hemangioendotheliomas
*rare benign vascular tumor in the neonate.
80% occur in first 6 months of life and more common in females.
masses appear complex, mostly solid hepatic lesions with variable hypo- or hyperechoic echotexture.
usually regress within the first year of life; life threatening due to CHF (congestive heart failure)
CFD will show blood flow in multiple tortuous vessels within and outside of the mass.
intrahepatic arteries show an increase in velocities.
*AV shunting may occur and cause high-output heart failure
Mesenchymal hamartoma
benign hamartomatous growth of mesenchymal tissue of unknown etiology.
more common in infants and children less than 2 years of age.
sono: appear as a large complex mass
surgical resection is required due to the risk of malignancy.
Focal nodular hyperplasia (FNH)
RARE in children, thought to be developmental hyperplastic lesion related to an area of congenital vascular malformation in the liver. asumptomatic and are more common in women.
sono: solitary, solid mass of varying echogenicity with a “central scar” sign (fibrous scar)
No risk of malignant transformation.
Liver adenomas
very rare in children.
commonly seen in flucogen storage disease, OPC use and steroid therapy ( can evolve into HCC)
may present with pain due to tumor hemorrhage. Surgical resection is recommended.
Liver tumors
malignant liver masses are rare in neonates.
Hepatoblastoma, hepatocellular carcinoma (HCC), liver mets
*hepatoblastoma’s are the most common malignant liver tumor in childhood.
hepatocellular carcinoma (HCC)are the 2nd most common malignant liver tumor in childhood.
Hepatoblastoma
*most common malignant liver tumor in childhood.
usually occur before the age of 3. present with asymptomatic enlargement of the liver. increase in serum AFP is seen.
mass is usually 10-12 cm at diagnosis. sono: solitary well-defined lesion which is more common in the right lobe. *PV invasion and lung mets are common.
- Hepatoblastomas are associated with:
Beckwith-Wiedemann syndrome, hemihypertrophy and familial adenomatous polyposis.
Hepatocellular carcinoma (HCC)
peaks at 4-5 years and again at 12-14 years of age.
half of patients affected have a preexisting condition :glycogen storage disease, hepatitis or cirrhosis following biliary atresia.
Solid masses of variable echogenicity are seen sonographically. PV invasion is common and serum AFP levels are elevated.
2nd most common malignant liver tumor in childhood.
Liver metastases
usually seen with neuroblastoma, wilms tumor, leukemia and lymphoma in children.
Hepatic cysts
may be congenital or acquired.
congenital hepatic cysts: occur when an intrahepatic biliary duct fails to involute.
acquired hepatic cyst: usually due to trauma or infection. typically solitary, usually benign and do not require follow-up. may appear complex due to hemorrhage or infection.
> 10, evaluate for PCKD.
Hepatic abcessses:
pyogenic
amebic
Pyogenic abscess
localized collection of pus in the hepatic parenchyma.
more common in the right lobe of the liver and are commonly multiple in children.
generally associated with: sepsis, leukemia
may be due to drug therapy, appendicitis, cholangitis, or immunocompromised children.
Amebic abscess
occur when a parasite from the intestines invades the liver via the PV. right liver more commonly affected.
*clinical history is important ?? travel
amebic abscesses are endemic to the tropics and spread person to person. Most frequent extraintestinal complication of an ambeic infection.
Echinococcal cyst (hydatid cyst)
due to parasitic tapeworm infestation associated with sheep and cattle raising countries. Eggs are swallowed and pass into the portal venous system where they hatch and move into the liver.
average size is 5cm and can grow 2-3 cm a year. calcifications appear during healing phase.
Echinococcal cyst (hydatid cyst) sono:
appearances vary depending on the stage of disease:
simple cyst
cyst within a cyst (cyst with detached endocyst)
cyst with “daughter cysts”
calcified mass
*sonographic “water lily” sign
Schistomsomiasis
invasion of the PV by the schistosoma ova.
It leads to portal HTN without cirrhosis.
PV becomes very echogenic due to fibrotic changes due to invasion. Lay eggs in PV wall.
RARE in children.
Schistosoma ova:
freshwater parasitic worms occurring in tropical and subtropical regions.
usually contracted from contaminated food and water.
Cirrhosis
usual forms in children: biliary and post-necrotic.
cirrhosis leads to portal HTN. the liver becomes nodular due to regenerating nodules. vascularity is not seen due to the abundance of connective tissue in the liver.
sono: shrunken with a nodular surgace and an enlarged caudate lobe (has its own blood supply, so it is spared)
Hepatitis
Inflamation of the liver.
may be due to: TORCH infections, biliary atresia, cystic fibrosis, or toxin accumulation in inherited metabolic diseases.
sono: enlarged hypoechoic liver and PV more echogenic giving a * “starry night” appearance.
Fatty Infiltration (steatosis)
accumulation of fat in the hepatocytes (liver cells). The liver appears hyperechoic and there is poor sound penetration.
reversible in most cases except when the steatosis leads to cirrhosis.
Causes of fatty infiltration in children:
early cirrhosis, chemotherapy, obesity, nephrotic syndrom, glycogen storage disease, hyperalimentation, malnutrition, alcohol abuse, steroid use,
*Reye’s syndrome, * cystic fibrosis (most common)
Liver transplants in children
chronic hepatitis, liver cancer, familial cholestasis, alpha-1- antitrysin deficiency, primary sclerosing cholangitis, glycogen storage disease, neonatal hemochromatosis, sudden acute failure (due to infection, drugs, poisons), tyrosinemia (metabolism error cuased by an enzyme defect
*biliary atresia (leads to liver failure), *wilson’s disease (copper accumulation in the liver.
Most common complication post liver transplant
*hepatic artery stenosis.
Pneumobilia and fluid collections are also commonly seen.
Rex shunt/bypass
used to manage portal HTN in children when TIPS may be technically difficult.
Rex bypass involves linking the SMV to the LPV and redirects flow into the liver.
portal flow is restored by bringing the mesenteric venous and splenic blood around the extrahepatic portal obstruction and restores hepatopedal flow.
Situs inversus
congenital condition in which the major visceral organs are reversed or mirrored from their normal position.
Biliary tract
composed of the gallbladder and the biliary ducts.
basic function is to drain the liver of bile and store the bile until needed to aid in digestion. GB holds bile, the bile is concentrated by the GB secreting mucous and absorbing water.
course of bile from GB to duodenum
GB composed of a fundus, neck and body. Neck narrows into the cystic duct which joins the common hepatic duct (CHD) to form the common bile duct (CBD). The CBD joins with the duct of wirsung to form the ampulla of vater. The flow of bile into the duodenum is controlled by the sphincter of Oddi.
Neonatal jaundice
result of elevated bilirubin in bloodstream.
2 types: unconjugated and conjugated.
Unconjugated bilirubin (indirect)
when bilirubin is released from the red blood cells that have been broken down (hemolysis)
common in newborns, if persists for more than 2 weeks it is consisdered persistent.
*unconjugated “toxic” hyperbilirubinemia
causes of unconjugated bilirubin
breast milk jaundice UTI hemolytic anemia hypothyroidism high GI obstruction
*breast milk jaundice
associated with breast feeding. an increase in indirect bilirubin in a breastfed newborn after the first 4-7 days of life. no identifiable cause.
*breastfeeding jaundice
first 3 days of life, caused by an insufficient production or intake of breastmilk.
Conjugated bilirubin (direct)
when the released bilirubin is converted by liver cells to a water-soluble form. This aids in fat digestion and turns stools dark.
*conjugated huperbilirubinemia is persistent jaundic caused by liver disease (bile duct obstruction) non-toxic
Causes of conjugated biliruin (direct)
biliary atresia (main cause) choledochal cyst neonatal hepatitis metabolism errors cystic fibrosis choledocolithiasis TPN intrahepatic biliary hypoplasia (alagille syndrome)
Biliary atresia
*progressive sclerosis of the extra- and proximal intrahepatic bile ducts and gallbladder.
acquired inflammation of the bile ducts or an inherited viral infection at birth which results in damage to segments of the biliary tree.
GB very small or absent
suspected if hyperbilirubinemia persists after 14 days of life. *more common in females.
- perinatal biliary atresia most common, presents 2-4 weeks of life
- fetal biliary atresia is rare
Kasai classification of biliary atresia
type I: obliteration of CBD, proximal ducts patent.
type IIa: atresia of hepatic duct, with cystic and common bile duct patent
typeIIb: cystic, common, and hepatic ducts obliterated
type III: (90%) discontinuity of right and left hepatic ducts to the level of the porta hepatis.
Infants with biliary atresia:
failure to thrive, cholestatic jaundice, pale stools and dark urine.
*more common in females
cirrhosis and portal HTN result and it is fatal without Kasai procedure (surgical drain) or liver transplant within the first 3 months of life.
Triangular cord sign
triangular echogenic cord of fibrous tissue seen in the porta hepatis. useful in evaluation of infants with cholestatic jaundice, helps with differential diagnosis of biliary atresia from neonatal hepatitis.
*more that 4mm thickness of the echogenic anterior wall of the right portal vein measured on longitudinal scan.
biliary atresia associated with:
polysplenia
absent IVC
situs inversus
some cardiac anomalies
Intrahepatic biliary hypoplasia (alagille syndrome)
autosomal dominant condition.
child has intrahepatic biliary hypoplasia, severe itching, and failure to thrive.
also have: characteristic triangular face, skeletal abnormalities,peripheral pulmonary stenosis, renal tubular disorders and eye defects. without transplant, only half survive into adult life.
Caroli disease
*non-obstructive, congenital, multifocal segmetal dilatation of the intrahepatic bile ducts.
ducts form cystic dilatations and are prone to sludge and calculi which puts the patient at risk for cholangitis.
associated with: congenital hepatic fibrosis, renal medullary cystic disease and choledochal cyst.
complications: cholangitis, choledocholithiasis, cholangicarcinoma and hepatic abscesses and sepsis.
Congenital hepatic fibrosis
Liver initially appears normal but eventually enlarges, especially the left lobe. Peri-portal fibrosis appears and increases with time. Cystic dilatations of the biliary tree are seen; this is the most diagnostic appearance.
**congenital hepatic fibrosis is one of the fibropolycystic diseases which include:
Caroli disease
ADPCKD
ARPCKD
Choledochal cysts
congenital biliary anomaly of the bile ducts. *There are 5 types, the most common is type I (80-90%)
*more common in Japanese females.
symptoms usually occur before age of 10
children present with: fever, abdominal pain, jaundice and palpable abd mass.
Choledochal cysts sono:
associated with:
sono: well-defined, fluid-filled cystic masses in the porta hepatis, and the GB and CBD and intrahepatic bile ducts are dilated.
associated: pancreatitis, cholangitis, hepatic abscess, cirrhosis, portal HTN, and cholangicarcinoma.
Cholecystitis
inflammation of the GB which may be acute or chronic. The GB wall appears thickened due to infection of the GB wall. RARE in pediactrics.
*GB disease is more common in children with sickle cell anemia
Thickened GB wall may be seen with:
Cholecystitis ascites due to heart,liver, or kidney failure veno-occulusive disease peritonitis and sepsis pancreatitis cholangitis leukemia kawasaki's dz
Cholelithiasis
stones in the GB, sludge is more common in children
Causes of gallstones in pediatric patient:
*sickle cell
crohn's dz
choledochal cysts
biliary tree obstruction
metabolic dz
hemolysis
sepsis
hemolytic anemia
TPN
RH problems
blood rransfusions
dehydration
obesity
bile duct anomalies
wilsons dz (too much copper in body; inherited)
*cystic fibrosis ("sticky" bile)Gallbladder sludge
thickened bile caused by bile stasis. Mostly seen in children on TPN or who have been extremely ill and not eating. May also be caused by an obstructed biliary tree and GB
Gallbladdr hydrops
*GB mucocele. the GB is massively dilated due to obstruction of the cystic duct.
The bile is reabsorbed and GB mucosa secretions or watery fluid fill the GB.
*Commonly seen in Kawasaki dz in children.
sono: large GB will be seen with anechoic contents and no ductal dilatation.
CBD sizes:
< 1 mm = neonates and infants < 1 year
<2 mm = <2 years
<4 mm = 2-12 years
<5 mm= adolescents
GB wall in children:
1-3 mm (no different than adults)
Pneumobilla:
air in the biliary tract which is associated with sphincter of Oddi incompetency, emphysematous cholecystitis or due to and ERCP, liver transplants.
Echogenic foci are seen in the ducts with comet-tail or reverberation artifacts.
