(Radiographics. 2000;20:173-195.)
© RSNA, 2000
US Approach to Jaundice in Infants and Children1
Julie A. Gubernick, MD,
Henrietta Kotlus Rosenberg, MD ,
Hakan Ilaslan, MD and
Ada Kessler, MD, 2
1 From the Department of Radiology, Albert Einstein Medical Center, 5501 Old York Rd, Philadelphia, PA 19141-3098. Presented as a scientific exhibit at the 1998 RSNA scientific assembly. Received April 27, 1999; revisions requested June 22 and received August 17; accepted September 22. Address reprint requests to J.A.G.
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Abstract
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High-resolution real-time ultrasonography (US) serves as an important tool for differentiation of obstructive and nonobstructive causes of jaundice in infants and children, independent of liver function. Unconjugated hyperbilirubinemia occurs in approximately 60% of normal term infants and in 80% of preterm infants. Persistence of neonatal jaundice beyond 2 weeks of age demands US evaluation to differentiate between the three most common causes: hepatitis, biliary atresia, and choledochal cyst. In all three conditions, the hepatic echotexture is diffusely coarse and hyperechoic, but this appearance may be seen in a variety of hepatic inflammatory, obstructive, and metabolic processes. Thus, hepatic scintigraphy and at times percutaneous liver biopsy are necessary to narrow the differential diagnosis and to identify patients who require more invasive techniques (eg, intraoperative cholangiography). US is useful for demonstrating inspissated bile and biliary duct stones. In infants, stones are usually secondary to obstructive congenital anomalies of the biliary tract, total parenteral nutrition, furosemide treatment, phototherapy, dehydration, infection, hemolytic anemia, and short-gut syndrome, whereas in older children, stones are usually associated with sickle cell disease, bowel resection, hemolytic anemia, and choledochal cyst. Jaundice in infants and children may also be due to cirrhosis, benign strictures, and neoplastic processes.
Index Terms: Bile ducts, abnormalities, 76.288 • Children, gastrointestinal tract • Hepatitis, 761.291 • Infants, gastrointestinal tract • Jaundice, 76.288, 761.291, 766.1492 • Bile ducts, cysts, 766.1492 • Liver, diseases, 76.28, 761.291 • Liver neoplasms, in infants and children, 761.30
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Introduction
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Unconjugated hyperbilirubinemia is a normal physiologic event that occurs in approximately 60% of normal full-term infants and in 80% of preterm infants. The bilirubin level normally increases by day 2–3 and peaks by day 5–7, reaching as high as 12 mg/dL in normal full-term babies and up to 14 mg/dL in normal premature infants by the end of the first week of life (1). Breast-fed babies may normally have an elevated bilirubin level until the end of the second week of life. However, the onset of jaundice within the first 24 hours of life, rate of rise of serum bilirubin levels greater than 5 mg/dL in 24 hours, direct bilirubin level greater than 1 mg/dL at any time, or the persistence or new onset of jaundice in infants 2 weeks of age or older may no longer be physiologic (2,3). In these cases, clinical and laboratory work-up is needed to identify the underlying infectious, metabolic, or structural causes of jaundice for which early therapy might improve outcome (2,4). Laboratory work-up may include liver function tests, testing for hepatitis B antigen, TORCH (toxoplasmosis, other [syphilis, hepatitis, zoster], rubella, cytomegalovirus, and herpes simplex [maternal infections]) titers, work-up for sepsis (blood, urine, cerebrospinal fluid), metabolic screening (
1-antitrypsin phenotype testing), and sweat test.
The advent of high-resolution real-time sonography has revolutionized the work-up of jaundice in infants and children. This noninvasive, nonionizing imaging modality is independent of liver function and serves as an important tool for differentiating between obstructive and nonobstructive causes of jaundice and is the imaging modality of choice for screening this patient population (2–6).
In this article, we present a broad overview of the subject, with discussions of the wide gamut of causes of jaundice (congenital, heritable, and acquired) in the pediatric patient and descriptions of the ultrasonographic (US) findings and those of correlative imaging studies when needed. We also describe a systematic approach for the US examination of these patients. By combining meticulous scanning with a thorough knowledge of the myriad of causes of jaundice in the pediatric patient, the radiologist can help provide an organized approach to the work-up of jaundice and thereby prevent unnecessary tests and facilitate prompt treatment.
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US Examination
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The US evaluation of infants and children with jaundice should consist of a systematic, thorough examination of the right upper quadrant, including the liver, bile ducts, gallbladder, pancreas, spleen, and portal vein. The US examination should also cover the entire abdomen and pelvis.
The size and texture of the liver should be thoroughly evaluated. The right hepatic lobe should not extend more than 1 cm below the costal margin in a young infant without pulmonary hyperaeration and should not extend below the right costal margin in older infants and children. The normal echotexture of the hepatic parenchyma in the pediatric liver does not differ from that seen in normal adult livers. The echogenicity is normally low to medium and homogeneous, and the peripheral portal venous vasculature is clearly seen (Fig 1) (2).
Intra- and extrahepatic biliary ducts should be carefully measured to exclude ductal dilatation. The common bile duct should measure less than 1 mm in neonates, less than 2 mm in infants up to 1 year old, less than 4 mm in older children, and less than 7 mm in adolescents and adults.
The gallbladder size and wall thickness should be measured. A normal gallbladder length is 1.5–3 cm in infants (<1 year old) and 3–7 cm in older children. The length of the gallbladder should not exceed that of the adjacent kidney (2,7–10). The gallbladder should also be evaluated for stones, sludge masses, pericholecystic fluid, and a sonographic Murphy sign.
The pancreas should be examined for size, echotexture, and evidence of dilatation of the pancreatic duct. The pancreatic head should measure 1.0–2.2 cm; the body, 0.4–1.0 cm; and the tail, 0.8–1.8 cm. The size of the pancreas should increase with the child's age (11). The normal pediatric pancreas is isoechoic or minimally hyperechoic compared with the liver. The cross-sectional diameter of the pancreatic duct should not exceed 1–2 mm (11).
Spleen size and texture must also be evaluated (12). The upper limits of normal splenic length range from 6.0 cm in infants 0–3 months old to 12.0 cm in children 12–15 years old (12).
The cross-sectional diameter of the portal vein is a helpful measurement in the diagnosis of portal hypertension. The mean portal vein measurement is 8.5 mm in children less than 10 years of age and 10 mm in patients 10–20 years old. Duplex and color Doppler sonography should be used to determine the presence and direction of flow.
A complete duplex and color Doppler examination of the biliary ducts and vessels is essential. A search for collateral channels (varices) and ascites should also be performed (11).
The remainder of the abdomen and pelvis should be thoroughly examined to exclude any evidence of neoplasia or lymphadenopathy.
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Causes and Diagnosis of Neonatal Jaundice
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The three most common causes of jaundice in neonates are hepatitis, biliary atresia, and choledochal cyst (2,6,7,13).
US is the imaging modality of choice for differentiating among these conditions. Because some of the US findings of hepatitis and biliary atresia overlap, the differential diagnosis of these entities is discussed in detail.
Neonatal Hepatitis
Neonatal hepatitis manifests at 1–4 weeks of age and is seen more commonly in male infants (Figs 2, 3). There are multiple causes of neonatal hepatitis including infections (virus, protozoa, spirochete, toxoplasmosis, rubella, cytomegalovirus, herpes, syphilis), metabolic disorders (1-antitrypsin deficiency), familial recurrent cholestasis, errors of metabolism such as nesidioblastosis (idiopathic hyperinsulin hypoglycemia of infancy), or idiopathic causes (2,3,7,8).
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Figure 2. Hepatitis in a 2-week-old boy with jaundice and an enlarged abdomen. Transverse sonogram demonstrates an enlarged liver with a diffusely coarse echotexture and a tiny gallbladder (GB). The peripheral portal venous vasculature is not visualized.
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Figure 3. Cytomegalovirus hepatitis in a young male infant with jaundice, hepatosplenomegaly, thrombocytopenia, and elevated levels of liver enzymes. Sagittal sonogram of the liver shows coarse echotexture with multiple, bright, often shadowing, echogenic foci (arrow) scattered throughout the liver. Plain radiography of the abdomen may show calcification.
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On sonograms, the liver may be normal sized or enlarged. The parenchymal echogenicity is increased, with decreased visualization of the peripheral portal venous vasculature. The biliary ductal system is unremarkable with a normal-sized gallbladder. In cases of severe hepatocellular dysfunction, the gallbladder may be reduced in size because of the decreased volume of bile.
In infants with poor biliary excretion and resultant underfilling of the gallbladder, sonographic differentiation between neonatal hepatitis and biliary atresia may be difficult, unless the common bile duct is clearly seen and amenable to accurate measurement. Thus, in unclear cases, hepatobiliary scintigraphy should be performed to assess whether there is normal bile excretion into the small intestines (2,14–18).
Biliary Atresia
Biliary atresia is seen twice as often in male infants as in female infants and is thought to result from inflammation of the hepatobiliary system (9,19–21). The three types of biliary atresia are outlined in Table 1.
A spectrum of changes may be seen sonographically in cases of biliary atresia, depending on the type and severity (2,4,15,20). The liver size may be either normal or increased. As with hepatitis, the echogenicity of the liver parenchyma may be either normal or increased, with decreased visualization of the peripheral portal venous vasculature (a finding indicative of fibrosis) (Fig 4). The intrahepatic bile ducts are typically not dilated. A bile duct remnant may be identified in the porta hepatis depending on the type of biliary atresia. A triangular or tubular, echogenic structure may be visualized in the porta hepatis. This finding has been called the ultrasonic "triangular cord" and correlates with fibrous tissue found in the porta hepatis at surgery. This sign is relatively specific for extrahepatic biliary atresia (21).
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Figure 4a. Biliary atresia in a 2-week-old boy with jaundice and hepatosplenomegaly. (a) Sagittal sonogram of the liver shows diffusely coarse echotexture, lack of visualization of the peripheral portal venous vasculature, and reduced beam penetration. There was hepatosplenomegaly, and the gallbladder measured only 8.2 mm in length. (b) Hepatobiliary scan obtained after a 35-minute delay demonstrates absence of activity in the central common bile duct and small intestine. Initial images (not shown) demonstrated poor uptake of the radionuclide by the liver.
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Figure 4b. Biliary atresia in a 2-week-old boy with jaundice and hepatosplenomegaly. (a) Sagittal sonogram of the liver shows diffusely coarse echotexture, lack of visualization of the peripheral portal venous vasculature, and reduced beam penetration. There was hepatosplenomegaly, and the gallbladder measured only 8.2 mm in length. (b) Hepatobiliary scan obtained after a 35-minute delay demonstrates absence of activity in the central common bile duct and small intestine. Initial images (not shown) demonstrated poor uptake of the radionuclide by the liver.
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Although the finding of a normal-sized gallbladder usually implies neonatal hepatitis, it may also be seen when the atretic common bile duct is distal to the insertion of the cystic duct. The finding of a small (<1.5-cm) gallbladder is non-specific and may be seen with either hepatitis or biliary atresia (13,15,22). Change in gallbladder size after a milk feeding suggests patency of the common hepatic and common bile ducts and is seen only with neonatal hepatitis (23).
A careful search for polysplenia should be made because of its association with biliary atresia in 10%–12% of cases (2,24). The abdomen should be examined for signs of end-stage liver disease, including ascites, hepatofugal flow in the portal and splenic veins, and collateral venous channels. Hepatobiliary scintigraphy is often indicated to distinguish between neonatal hepatitis and biliary atresia (2,14,20).
Patients with Alagille syndrome (arteriohepatic dysplasia) may also present with jaundice in the newborn period and with US findings similar to those of biliary atresia. In these patients, the histologic analysis reveals paucity and hypoplasia of the interlobar ducts. The presence of associated congenital anomalies (abnormal facies, butterfly vertebrae, pulmonic stenosis, and complex congenital heart disease) should help distinguish this entity from biliary atresia (25).
Differential Diagnosis between Hepatitis and Biliary Atresia
Hepatobiliary Scintigraphy.—Infants with biliary atresia less than 3 months of age typically have a normal hepatic extraction fraction; however, there is no excretion of the radionuclide into the small intestine. In affected infants older than 3 months, hepatic extraction of the radionuclide is decreased and there is no passage of radiopharmaceutical into the small intestine. The presence of small bowel activity excludes biliary atresia as the diagnosis; however, differentiation between biliary atresia and neonatal hepatis is nearly impossible in the absence of small bowel activity when there is poor hepatocellular function. Administration of phenobarbital before the procedure may be useful in enhancing hepatocellular function in patients with hepatitis, thus allowing small bowel activity to be seen (2,14,20).
MR Imaging.—MR cholangiopancreatography may also provide useful information for evaluating the patency of intra- and extrahepatic biliary ducts (26). MR cholangiography uses signal from the bile within the ducts to allow visualization of the biliary system. Therefore, MR imaging is best used to evaluate the extrahepatic biliary ductal system. Complete visualization of the extrahepatic biliary system excludes biliary atresia as a diagnosis (27).
Liver Biopsy.—When neonatal hepatitis and biliary atresia cannot be differentiated with imaging studies, percutaneous liver biopsy may be necessary (2), especially when small bowel activity cannot be demonstrated at hepatobiliary scintigraphy. In neonatal hepatitis, there are multinucleated giant cells with hepatic parenchymal disruption and relatively little bile within the bile duct canaliculi (Fig 5). In biliary atresia, proliferation of the small intrahepatic bile ducts, absence of the extrahepatic biliary ducts, periportal fibrosis, and occasionally multinucleated giant cells may be seen (Fig 6). There may be acute or chronic inflammation, degeneration of the duct epithelium, or frank scarring in the extrahepatic biliary remnant (22).
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Figure 5. Pathologic changes in neonatal hepatitis. Low-power photomicrograph (hematoxylin-eosin stain) demonstrates lobular disarray, giant cell transformation, and mononuclear lobular infiltrate.
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Figure 6. Pathologic changes in biliary atresia. Low-power photomicrograph (hematoxylin-eosin stain) demonstrates a marked degree of fibrosis, bile duct proliferation, and portal inflammation.
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Cholangiography.—Cholangiography is indicated when the imaging and pathologic findings suggest the diagnosis of biliary atresia. Cholangiography may be performed percutaneously, endoscopically, or intraoperatively via the gallbladder (28). When extrahepatic biliary atresia is confirmed intraoperatively, a Kasai portoenterostomy is performed. The best results are achieved in infants who are operated on before 60 days of age, with a success rate of 91%. Dramatically poor results (17% success rate) are seen when surgery is performed beyond 90 days of age because of the presence of cirrhosis (29). Liver transplantation becomes the only option in these older infants and in babies with intrahepatic biliary atresia (2).
Choledochal Cyst
Choledochal cyst is an uncommon cause of obstructive jaundice. Several different types of choledochal cysts have been described (Fig 7) (Table 2). It is more frequently seen in female and Asian infants. Patients may be asymptomatic or may present with any or all of the classic triad of pain, jaundice, and a right upper quadrant mass (2,31–33). This condition is thought to be related to an abnormal insertion of the common bile duct into the pancreatic duct, which causes reflux of pancreatic enzymes into the pancreatic duct. This reflux causes a chemical cholangitis and eventually leads to dilatation of the common bile duct as well as the entire biliary tree (Figs 8–10) (30,31,34,35).
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Figure 8a. Choledochal cyst (type IA) in a 6-year-old girl with jaundice and clinical evidence of pancreatitis. (a) Transverse sonogram shows a minimally enlarged pancreas (P) and a 4-cm anechoic cyst (C) in the region of the pancreatic head. (b) Transverse sonogram of the liver demonstrates dilated intrahepatic ducts (arrows) and coarse liver echotexture thought to be due to cholestasis. (c) Color Doppler image helps confirm the absence of flow in the dilated common hepatic duct, which communicates with the choledochal cyst. This finding was confirmed with duplex Doppler US.
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Figure 8b. Choledochal cyst (type IA) in a 6-year-old girl with jaundice and clinical evidence of pancreatitis. (a) Transverse sonogram shows a minimally enlarged pancreas (P) and a 4-cm anechoic cyst (C) in the region of the pancreatic head. (b) Transverse sonogram of the liver demonstrates dilated intrahepatic ducts (arrows) and coarse liver echotexture thought to be due to cholestasis. (c) Color Doppler image helps confirm the absence of flow in the dilated common hepatic duct, which communicates with the choledochal cyst. This finding was confirmed with duplex Doppler US.
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Figure 8c. Choledochal cyst (type IA) in a 6-year-old girl with jaundice and clinical evidence of pancreatitis. (a) Transverse sonogram shows a minimally enlarged pancreas (P) and a 4-cm anechoic cyst (C) in the region of the pancreatic head. (b) Transverse sonogram of the liver demonstrates dilated intrahepatic ducts (arrows) and coarse liver echotexture thought to be due to cholestasis. (c) Color Doppler image helps confirm the absence of flow in the dilated common hepatic duct, which communicates with the choledochal cyst. This finding was confirmed with duplex Doppler US.
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Figure 9a. Choledochal cyst (type IC) with biliary atresia in a female neonate with jaundice. (a) Sagittal sonogram shows a fusiform choledochal cyst (arrow) involving the common bile duct. The surrounding hepatic echotexture is coarse. The gallbladder (not shown) was tiny. (b) Intraoperative cholangiogram demonstrates a small gallbladder (GB) and choledochal cyst (CC). (c) Intraoperative cholangiogram obtained after a stronger injection of contrast material reveals atretic intrahepatic biliary ducts consistent with biliary atresia. A hepatobiliary scan (not shown) showed no excretion of the radiopharmaceutical.
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Figure 9b. Choledochal cyst (type IC) with biliary atresia in a female neonate with jaundice. (a) Sagittal sonogram shows a fusiform choledochal cyst (arrow) involving the common bile duct. The surrounding hepatic echotexture is coarse. The gallbladder (not shown) was tiny. (b) Intraoperative cholangiogram demonstrates a small gallbladder (GB) and choledochal cyst (CC). (c) Intraoperative cholangiogram obtained after a stronger injection of contrast material reveals atretic intrahepatic biliary ducts consistent with biliary atresia. A hepatobiliary scan (not shown) showed no excretion of the radiopharmaceutical.
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Figure 9c. Choledochal cyst (type IC) with biliary atresia in a female neonate with jaundice. (a) Sagittal sonogram shows a fusiform choledochal cyst (arrow) involving the common bile duct. The surrounding hepatic echotexture is coarse. The gallbladder (not shown) was tiny. (b) Intraoperative cholangiogram demonstrates a small gallbladder (GB) and choledochal cyst (CC). (c) Intraoperative cholangiogram obtained after a stronger injection of contrast material reveals atretic intrahepatic biliary ducts consistent with biliary atresia. A hepatobiliary scan (not shown) showed no excretion of the radiopharmaceutical.
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Figure 10a. Choledochal cyst with biliary atresia in a newborn who presented with increasing jaundice and in whom a cystic abdominal mass had been noted at prenatal US. (a) Sagittal sonogram of the right upper quadrant shows a large cystic mass in the porta hepatis. The mass, a choledochal cyst (CC), tapers cranially. The liver echotexture is coarse, and none of the intrahepatic bile ducts or a normal common bile duct are visualized. A = aorta, HV = hepatic vein, pv = portal vein. (b) Color Doppler image shows biliary vessels surrounding the avascular choledochal cyst (CC). (c) Intraoperative cholangiogram shows aqueous contrast material filling the gallbladder (GB) and choledochal cyst (CC) with no filling of the intrahepatic bile ducts.
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Figure 10b. Choledochal cyst with biliary atresia in a newborn who presented with increasing jaundice and in whom a cystic abdominal mass had been noted at prenatal US. (a) Sagittal sonogram of the right upper quadrant shows a large cystic mass in the porta hepatis. The mass, a choledochal cyst (CC), tapers cranially. The liver echotexture is coarse, and none of the intrahepatic bile ducts or a normal common bile duct are visualized. A = aorta, HV = hepatic vein, pv = portal vein. (b) Color Doppler image shows biliary vessels surrounding the avascular choledochal cyst (CC). (c) Intraoperative cholangiogram shows aqueous contrast material filling the gallbladder (GB) and choledochal cyst (CC) with no filling of the intrahepatic bile ducts.
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Figure 10c. Choledochal cyst with biliary atresia in a newborn who presented with increasing jaundice and in whom a cystic abdominal mass had been noted at prenatal US. (a) Sagittal sonogram of the right upper quadrant shows a large cystic mass in the porta hepatis. The mass, a choledochal cyst (CC), tapers cranially. The liver echotexture is coarse, and none of the intrahepatic bile ducts or a normal common bile duct are visualized. A = aorta, HV = hepatic vein, pv = portal vein. (b) Color Doppler image shows biliary vessels surrounding the avascular choledochal cyst (CC). (c) Intraoperative cholangiogram shows aqueous contrast material filling the gallbladder (GB) and choledochal cyst (CC) with no filling of the intrahepatic bile ducts.
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In Caroli disease (type V choledochal cysts), there are single or multiple intrahepatic cysts that converge toward the porta hepatis and represent saccular dilatation of the bile ducts (Figs 11, 12) (2,36). The portal radicals may be either partially or completely surrounded by dilated ducts (37,38), and there may be dilatation of the common bile duct (34,39). Hepatic fibrosis, portal hypertension, and polycystic kidney disease are associated (2, 40,41). Most patients present as young adults with fever, pain, and transient jaundice. Rarely, patients may present in the neonatal period (41–44).
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Figure 11a. Caroli disease in a 7-year-old girl with jaundice and intermittent right upper quadrant pain. (a) Transverse sonogram demonstrates coarse liver texture with dilatation of the intrahepatic bile ducts with a cystlike projection from the left intrahepatic duct (arrow). (b) Sagittal sonogram of the porta hepatis shows a dilated common bile duct (calipers) and cystlike projection (arrow) arising from the common hepatic duct (arrowheads). (c) Intraoperative cholangiogram shows dilated common hepatic and common bile ducts with a cyst (arrow) arising from the common hepatic duct (arrowheads).
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Figure 11b. Caroli disease in a 7-year-old girl with jaundice and intermittent right upper quadrant pain. (a) Transverse sonogram demonstrates coarse liver texture with dilatation of the intrahepatic bile ducts with a cystlike projection from the left intrahepatic duct (arrow). (b) Sagittal sonogram of the porta hepatis shows a dilated common bile duct (calipers) and cystlike projection (arrow) arising from the common hepatic duct (arrowheads). (c) Intraoperative cholangiogram shows dilated common hepatic and common bile ducts with a cyst (arrow) arising from the common hepatic duct (arrowheads).
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Figure 11c. Caroli disease in a 7-year-old girl with jaundice and intermittent right upper quadrant pain. (a) Transverse sonogram demonstrates coarse liver texture with dilatation of the intrahepatic bile ducts with a cystlike projection from the left intrahepatic duct (arrow). (b) Sagittal sonogram of the porta hepatis shows a dilated common bile duct (calipers) and cystlike projection (arrow) arising from the common hepatic duct (arrowheads). (c) Intraoperative cholangiogram shows dilated common hepatic and common bile ducts with a cyst (arrow) arising from the common hepatic duct (arrowheads).
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Complications of choledochal cysts include cholelithiasis, choledocholithiasis, pancreatitis, abscess, malignancy, and cirrhosis (2,31,34,45).
At US, choledochal cysts of types I, II, or III appear as a simple cyst in the region of the common bile duct, which can be separated from the gallbladder. The communication with the biliary ductal system must be demonstrated in order to make the diagnosis of choledochal cyst. The intrahepatic ducts may or may not be dilated (46, 47). Depending on the type of choledochal cyst, other intrahepatic cysts may or may not be demonstrated. The pancreas and pancreatic duct should be examined for evidence of pancreatitis or ductal dilatation. Although hepatobiliary scintigraphy may demonstrate accumulation of radiopharmaceutical within a cyst and lack of passage into the small intestine, at times the choledochal cyst does not fill with the radionuclide and the diagnosis can be missed (2,14). Therefore, when a choledochal cyst is demonstrated sonographically, cholangiography should be the next step. MR cholangiography may also be useful in preoperative assessment of these lesions (45). An algorithm for the differentiation of hepatitis, biliary atresia, and choledochal cyst is shown in Figure 13.
A choledochal cyst may be confused with several other cystic lesions, including hepatic cyst, enteric duplication cyst, pancreatic pseudocyst, hepatic artery aneurysm, and spontaneous perforation of the common bile duct. These entities can all be differentiated with a careful scanning approach and the use of duplex and color Doppler imaging. An enteric duplication cyst most often has the characteristic intestinal signature, the "muscular rim sign," which consists of a brightly echoic inner rim (mucosa) and a hypoechoic outer rim (muscular layer) (48). Hepatic artery aneurysm may be differentiated with Doppler US (2).
Inspissated Bile Syndrome
Inspissated bile syndrome is an uncommon cause of jaundice in neonates. Sludge may be seen within the gallbladder as low-level echoes within the lumen (Fig 14), at times dependent. Inspissated bile is slightly more echogenic but does not cause shadowing. It may also be seen within the biliary ducts associated with partial or complete biliary ductal obstruction. The affected ducts may blend with the surrounding hepatic parenchyma, causing silhouetting of the bile ducts and thus difficulty in determining that the ducts are dilated (2).
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Figure 14a. Inspissated bile syndrome in a 2-month-old infant with jaundice and dehydration. (a) Oblique sonogram of the porta hepatis shows a dilated tubular structure (diameter, 7.2 mm) containing a fluid-debris level (arrow) and surrounded by coarse, hyperechoic liver texture due to cholestasis. (b) Color Doppler image helps confirm that the tubular structure anterior to the portal vein (PV) is a markedly dilated common bile duct (CBD). Note sludge within the gallbladder (GB). (c) On another color Doppler image, intrahepatic ductal dilatation (arrows) is evident.
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Figure 14b. Inspissated bile syndrome in a 2-month-old infant with jaundice and dehydration. (a) Oblique sonogram of the porta hepatis shows a dilated tubular structure (diameter, 7.2 mm) containing a fluid-debris level (arrow) and surrounded by coarse, hyperechoic liver texture due to cholestasis. (b) Color Doppler image helps confirm that the tubular structure anterior to the portal vein (PV) is a markedly dilated common bile duct (CBD). Note sludge within the gallbladder (GB). (c) On another color Doppler image, intrahepatic ductal dilatation (arrows) is evident.
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Figure 14c. Inspissated bile syndrome in a 2-month-old infant with jaundice and dehydration. (a) Oblique sonogram of the porta hepatis shows a dilated tubular structure (diameter, 7.2 mm) containing a fluid-debris level (arrow) and surrounded by coarse, hyperechoic liver texture due to cholestasis. (b) Color Doppler image helps confirm that the tubular structure anterior to the portal vein (PV) is a markedly dilated common bile duct (CBD). Note sludge within the gallbladder (GB). (c) On another color Doppler image, intrahepatic ductal dilatation (arrows) is evident.
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Inspissated bile syndrome may be associated with massive hemolysis (Rh incompatibility), hemorrhage (intraabdominal, intracranial, or retroperitoneal), and increased enterohepatic circulation in various intestinal diseases (Hirschsprung disease, intestinal atresias, and stenoses) (49–51).
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Causes and Diagnosis of Jaundice in Older Children
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The multiple causes of jaundice in older children can be divided into primary diseases of the hepatocytes and obstructive causes.
Hepatocellular disease can be subdivided into hepatitis (both acute and chronic) and metabolic. Acute hepatitis may be caused by infection, toxic agents, or drugs. Its US appearance depends more on the severity and stage of disease than on the causative agent. The liver size may be normal or enlarged, with diffuse decrease in the parenchymal echogenicity and brightly echogenic portal venous walls (Fig 15) due to edema in the hepatocytes. The gallbladder wall may be diffusely thickened. In patients with chronic active hepatitis, sonograms generally show increased echogenicity of the hepatic parenchyma, with a coarsened echotexture and decreased visualization of the peripheral portal venous vasculature (Fig 16) (52,53).
Metabolic causes of jaundice include Wilson disease, cystic fibrosis, glycogen storage disease, tyrosinuria, and 1-antitrypsin deficiency. The US appearances of all of these disorders are nonspecific, with the liver often appearing hyperechoic with decreased visualization of the peripheral portal venous vasculature. The sonographic findings should be correlated with clinical information and laboratory results. At times, liver biopsy may be necessary to confirm the diagnosis (2,52,53).
Biliary obstruction resulting in jaundice may be related to neoplasms, benign strictures (rare in children), or stone disease. Hepatic masses are relatively rare in children and account for approximately 5%–6% of all pediatric intraabdominal masses. Although hepatic malignancies are the most common gastrointestinal malignancy in children, they account for less than 2% of all pediatric malignancies. US is the modality of choice for the examination of children suspected of having an abdominal mass (54).
Neoplasms
Hepatoblastoma is the most common primary liver tumor in children and is usually seen in infants and children less than 3 years old (54–56). Typically, patients present with a palpable mass, but jaundice, pain, anorexia, or weight loss may be present as well. The mass is typically large, solid, and well defined, with variable echogenicity and often including calcifications (Fig 17) (54, 55,57).
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Figure 17. Hepatoblastoma in a 7-month-old boy with an abdominal mass. Transverse sonogram demonstrates a heterogeneous solid mass in the right hepatic lobe (arrows) that contains shadowing calcifications (arrowhead).
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Hepatocellular carcinoma is seen in older children, with a peak prevalence at 12–14 years of age, and less commonly in children less than 4–5 years old (54,58). Approximately 50% of children who develop hepatocellular carcinoma have a preexisting liver condition such as hepatitis, glycogen storage disease, tyrosinemia, cirrhosis, hemochromatosis, or 1-antitrypsin deficiency (54,59). Hepatocellular carcinoma has variable echogenicity, either hypo-, iso-, or hyperechoic relative to the surrounding liver parenchyma (Fig 18). Calcifications are rare. In the presence of underlying liver disease, the surrounding liver parenchyma may be abnormal (53).
Other hepatic malignancies in children are even more rare and include angiosarcoma, fibrolamellar hepatocellular carcinoma, rhabdomyosarcoma of the biliary tree (Fig 19), undifferentiated embryonal sarcoma, angiosarcoma, rhabdoid tumor, lymphosarcoma, and endodermal sinus tumor. The sonographic appearances of these lesions are nonspecific, and definitive diagnosis is made with biopsy (54,60).
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Figure 19a. Rhabdomyosarcoma of the common bile duct in a 7-year-old boy with jaundice, hepatomegaly, and itching. (a) Transverse scan of the pancreas (P) shows a round, solid heterogeneous mass (arrows) in the region of the pancreatic head. (b) Oblique sonogram of the porta hepatis shows the solid mass (arrows) in the markedly dilated common bile duct (CBD). GB = gallbladder, PV = portal vein. (c) Transverse sonogram of the liver demonstrates dilated intrahepatic ducts (arrow), coarse liver texture thought to be due to cholestasis, and a normal gallbladder (GB). (d) Intraoperative cholangiogram helps confirm the presence of the large mass with irregular borders filling the distal common bile duct (arrows).
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Figure 19b. Rhabdomyosarcoma of the common bile duct in a 7-year-old boy with jaundice, hepatomegaly, and itching. (a) Transverse scan of the pancreas (P) shows a round, solid heterogeneous mass (arrows) in the region of the pancreatic head. (b) Oblique sonogram of the porta hepatis shows the solid mass (arrows) in the markedly dilated common bile duct (CBD). GB = gallbladder, PV = portal vein. (c) Transverse sonogram of the liver demonstrates dilated intrahepatic ducts (arrow), coarse liver texture thought to be due to cholestasis, and a normal gallbladder (GB). (d) Intraoperative cholangiogram helps confirm the presence of the large mass with irregular borders filling the distal common bile duct (arrows).
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Figure 19c. Rhabdomyosarcoma of the common bile duct in a 7-year-old boy with jaundice, hepatomegaly, and itching. (a) Transverse scan of the pancreas (P) shows a round, solid heterogeneous mass (arrows) in the region of the pancreatic head. (b) Oblique sonogram of the porta hepatis shows the solid mass (arrows) in the markedly dilated common bile duct (CBD). GB = gallbladder, PV = portal vein. (c) Transverse sonogram of the liver demonstrates dilated intrahepatic ducts (arrow), coarse liver texture thought to be due to cholestasis, and a normal gallbladder (GB). (d) Intraoperative cholangiogram helps confirm the presence of the large mass with irregular borders filling the distal common bile duct (arrows).
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Figure 19d. Rhabdomyosarcoma of the common bile duct in a 7-year-old boy with jaundice, hepatomegaly, and itching. (a) Transverse scan of the pancreas (P) shows a round, solid heterogeneous mass (arrows) in the region of the pancreatic head. (b) Oblique sonogram of the porta hepatis shows the solid mass (arrows) in the markedly dilated common bile duct (CBD). GB = gallbladder, PV = portal vein. (c) Transverse sonogram of the liver demonstrates dilated intrahepatic ducts (arrow), coarse liver texture thought to be due to cholestasis, and a normal gallbladder (GB). (d) Intraoperative cholangiogram helps confirm the presence of the large mass with irregular borders filling the distal common bile duct (arrows).
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Infantile hemangioendothelioma is a benign liver lesion seen in young infants (Fig 20). These infants usually present with high output congestive heart failure and may also have thrombocytopenia. These lesions are typically heterogeneous and may be either hypo- or hyperechoic, with calcifications noted in up to 50% of cases (54, 61). Duplex and color Doppler US evaluation is extremely helpful in demonstrating the vascular components of the mass. Sonography is the ideal imaging modality for serial imaging of these often large masses because they spontaneously involute (54,56). Multiple smaller hemangiomas with variable echogenicity (usually hypo- or hyperechoic) may also be demonstrated throughout the liver. These lesions may also resolve spontaneously.
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Figure 20a. Hemangioendothelioma in a 9-month-old boy with hepatomegaly. (a) Transverse image obtained with Elegra SieScape technology (Siemens Medical Systems, Iselin, NJ) demonstrates a large complex mass occupying most of the anterior portion of the right lobe of the liver (arrows). Note small calcifications (arrowhead). (b) Power color Doppler image demonstrates multiple venous channels within the mass.
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Figure 20b. Hemangioendothelioma in a 9-month-old boy with hepatomegaly. (a) Transverse image obtained with Elegra SieScape technology (Siemens Medical Systems, Iselin, NJ) demonstrates a large complex mass occupying most of the anterior portion of the right lobe of the liver (arrows). Note small calcifications (arrowhead). (b) Power color Doppler image demonstrates multiple venous channels within the mass.
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Mesenchymal hamartoma most often occurs in children less than 2 years of age and is most often a complex mass with cystic elements and possible calcifications. Hepatocellular adenomas are rare in children but may be seen in patients with glycogen storage disease (Fig 21) and Fanconi anemia. These lesions may have variable echogenicity, with the hyperechoic lesions having a well-defined rim of decreased echogenicity (54,56).
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Figure 21. Glycogen storage disease with hepatocellular adenoma in an older teenage boy with jaundice and hepatomegaly. Transverse hepatic sonogram demonstrates coarse liver texture and a slightly hypoechoic, rounded mass posteromedially in the right lobe (calipers). The mass proved to be an adenoma.
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Metastatic disease to the liver may rarely manifest with jaundice. In children, secondary tumors are most often due to neuroblastoma or Wilms tumor, but they may also be seen with leukemia and lymphoma. Stage IV-S neuroblastoma may manifest with diffuse heterogeneous involvement of the entire liver (54,56), along with a primary adrenal mass, lymphadenopathy, and bone marrow involvement but no skeletal metastases (Fig 22).
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Figure 22. Neuroblastoma in a newborn girl with jaundice and a prenatal diagnosis of abdominal tumor. Sagittal sonogram of the right upper quadrant demonstrates a brightly echoic, enlarged adrenal gland (arrows) as well as multiple ill-defined, brightly echoic nodular areas throughout the liver (arrowheads). RK = right kidney.
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Cholelithiasis and Choledocholithiasis
Cholelithiasis and choledocholithiasis are uncommon causes of jaundice in children and are even more rare in neonates (2,62). Stones are typically brightly echoic shadowing foci, which are freely mobile when located within the gallbladder lumen (Fig 23). Tumefactive sludge is an echogenic, nonshadowing, mobile structure within the gallbladder lumen (Fig 24). Associated intra- and extrahepatic biliary ductal ectasia including the "parallel channel sign" should be looked for (63). Cholelithiasis in neonates and young infants is usually secondary to predisposing conditions such as obstructive congenital anomalies of the biliary tract (29); a history of total parenteral nutrition, furosemide treatment, or phototherapy; dehydration; infection; hemolytic anemias; and short-gut syndrome (51,62,64–66). In older children, causes of biliary stones include sickle cell disease (67), cystic fibrosis (68), malabsorption, total parenteral nutrition, Crohn disease, intestinal resection, hemolytic anemia, and choledochal cyst (69–71). Choledocholithiasis manifests as brightly echogenic, shadowing structures within the biliary ducts and is usually associated with ductal dilatation (Fig 25).
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Figure 25a. Choledocholithiasis in a 7-year-old boy with right upper quadrant pain and jaundice. (a) Oblique sonogram of the porta hepatis shows dilatation of the common hepatic (CHD) and common bile ducts (CBD). There was also mild dilatation of the intrahepatic bile ducts. (b)Transverse sonogram of the pancreas (P) and gallbladder (GB) demonstrates an obstructing stone (arrow) in the distal most part of the common bile duct.
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Figure 25b. Choledocholithiasis in a 7-year-old boy with right upper quadrant pain and jaundice. (a) Oblique sonogram of the porta hepatis shows dilatation of the common hepatic (CHD) and common bile ducts (CBD). There was also mild dilatation of the intrahepatic bile ducts. (b)Transverse sonogram of the pancreas (P) and gallbladder (GB) demonstrates an obstructing stone (arrow) in the distal most part of the common bile duct.
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Hydrops of the gallbladder may manifest as either a mass or pain in the right upper quadrant (72). The gallbladder is massively distended but has a normal wall thickness. The gallbladder measures more than 3 cm in length in infants less than 1 year old and more than 7 cm in length in older children and changes from an ovoid shape to a biconvex configuration (9,66). Typically, there is no evidence of either intra- or extrahepatic biliary ductal dilatation. The gallbladder distention may be due to thickened bile, which causes transient obstruction, but most commonly results from biliary stasis secondary to dehydration or prolonged fasting (73,74). Other conditions associated with gallbladder hydrops include Kawasaki syndrome (mucocutaneous lymph node syndrome), a history of total parenteral nutrition, scarlet fever, sepsis, leptospirosis, ascariasis, typhoid fever, and familial Mediterranean fever (75). Once the underlying condition is corrected, the hydropic gallbladder may resume its normal configuration (9).
Acute cholecystitis is uncommon in infants and children. As in adults, it may be either calculous or acalculous. Fifty percent of pediatric cases are caused by stones obstructing the cystic duct (76). Acalculous cholecystitis is often associated with recent surgery, burns, sepsis, debilitation, and prolonged bile stasis with cystic duct obstruction. Cholecystitis is caused by organisms that invade the mucosa of the gallbladder wall and cause inflammation. Complications of acute cholecystitis include gangrene, emphysema, and perforation.
In cholecystitis, the gallbladder wall may or may not be thickened (>3 mm) (Fig 26); thus, the finding of a positive sonographic Murphy sign is an important observation. It is also important to examine the wall for irregularities that might suggest gangrenous changes, for brighter areas with "dirty" shadowing indicative of emphysema, and for pericholecystic fluid suggestive of perforation. Hepatobiliary scintigraphy may be useful in suspected cases of acute cholecystitis in which the US findings are equivocal (10,77–79).
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Figure 26. Acalculous cholecystitis in a young child with jaundice, right upper quadrant pain, vomiting, and fever. Sagittal sonogram shows marked thickening of the gallbladder wall (calipers).
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Cirrhosis
Cirrhosis is rare in neonates but may occur in older children and cause jaundice. This chronic destruction of hepatic parenchyma with replacement by fibrosis and nodular regeneration may be caused by chronic hepatitis, congenital hepatic fibrosis, biliary atresia, cystic fibrosis, metabolic disease (Wilson disease, glycogen storage disease, tyrosinemia, galactosemia, 1-antitrypsin deficiency), Budd-Chiari syndrome, and total parenteral nutrition (2).
At US, the right hepatic lobe and medial segment of the left lobe are often small, with compensatory hypertrophy of the lateral segment of the left and caudate lobes (80). The hepatic echotexture is coarsened (Figs 27, 28) and often heterogeneous with a nodular parenchymal pattern. There is decreased penetration of the sound beam through the hepatic parenchyma, which contains fibrous tissue and at times multiple regenerating nodules. Secondary signs of cirrhosis, including ascites and portal hypertension, are often seen.
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Figure 27. Cirrhosis in a young child. Sagittal sonogram of the liver demonstrates typical findings of a small coarse liver with irregular borders (arrows) surrounded by ascites (A).
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Abstract
Introduction
