Diagnostic ultrasound ( PDFDrive )

CHAPTER 51 The Pediatric Liver and Spleen 1741
Causes of Steatosis
Drugs
Acetylsalicylic acid
Tetracycline
Valproate (and other antiepileptic medications)
Warfarin (Coumadin)
Toxins
Alatoxin
Hypoglycine
Alcohol abuse
Metabolic liver disease
Galactosemia
Fructose intolerance
Reye syndrome
Obesity
Corticosteroid therapy
Hyperlipidemia
Diabetes
Malnutrition
Nephrotic syndrome
Cystic ibrosis
CIRRHOSIS
he usual forms of cirrhosis in childhood are biliary and post
necrotic. Morphologically, the cirrhotic liver consists of regenerating
nodules devoid of central veins and surrounded by variable
amounts of connective tissue. Hepatic architecture is suiciently
distorted to disturb hepatic circulation and hepatocellular function.
Increased resistance to blood low through the liver leads
to portal hypertension.
he sonographic appearance of the liver depends on the
severity of the cirrhosis. With progressive replacement of hepatocytes
by ibrous tissue, the liver attenuates sound increasingly,
and sound penetration of the liver, even with low-frequency (2
or 3 MHz) transducers, becomes diicult. he macronodules of
advanced cirrhosis become visible sonographically at the surface
of the liver (contrasted to the neighboring lesser omentum,
peritoneum, or ascites, if present) or within its substance (nodular
architecture, increased hyperechogenic ibrous tissue around
portal vein branches and the ligamentum teres). 26 he caudate
lobe is oten prominent 28 (Fig. 51.12). Parts of segment 4 of the
right lobe of the liver may atrophy in advanced disease.
CHOLELITHIASIS
Gallstones are less common in children than in adults and are
usually related to an associated disease. heir composition can
be mixed or of calcium bilirubinate. he “adult” cholesterol stone
is rare except in children with cystic ibrosis. 29 Gallstones are
mobile and hyperechogenic, and they cast acoustic shadows only
if they are of appropriate size and composition.
In some children, especially those receiving total parenteral
nutrition, thick bile can be observed to form sludge, loosely
formed “sludge balls” or “tumefactive sludge,” and inally stones,
when serial sonograms are performed over several weeks (Fig.
51.13). Stasis of bile low is the probable cause of sludge and
stone formation, also seen in utero and in premature infants and
usually regressing spontaneously. 30
Gallbladder wall thickening occurs in children with acute
hepatitis, hypoalbuminemia, obstructed hepatic venous return,
and ascites. 22,23 he classic signs of impacted gallstone, thick
gallbladder wall, and luid around the gallbladder seen in adults
with acute cholecystitis are rare in children. he gallbladder
becomes dilated and rounded (rather than the normal oval shape)
in fasting children (especially infants receiving total parenteral
nutrition), children with sepsis (especially streptococcal), and
those in the acute phase of Kawasaki disease. When distended,
the gallbladder may become tender and painful. It heals with
the underlying disease. Acalculous cholecystitis in children is
rare and should be diagnosed only if no disease causing gallbladder
distention or wall edema is found. 31
Diseases Associated With Gallstones
in Children
HEMATOPOIETIC
Hemolytic anemias or hemolysis (artiicial heart valve)
Rh incompatibility
Blood transfusions
Sickle cell anemia
GASTROINTESTINAL
Cystic ibrosis
Bile duct anomalies
Ileal dysfunction (Crohn disease, short bowel)
Total parenteral nutrition
Metabolic liver diseases
OTHER
Immobilization (scoliosis surgery)
Dehydration
Obesity
Sepsis
Oral contraceptives
LIVER TUMORS
Identiication
It is sometimes diicult to deine the origin of an abdominal
mass, especially when it is large. he following questions are
helpful in tracing a mass to hepatic origin:
• Vascular anatomy: Can a feeding hepatic vessel be identiied
by means of Doppler sonography? Are segmental portal
veins displaced or invaded by the tumor 32 ? What liver segments
are involved? Is the main hepatic artery enlarged?
(his usually signals the presence of a highly vascular
hemangioendothelioma.)
• Biliary anatomy: Are the bile ducts normal? Has the gallbladder
been identiied?
• Anatomy of the abdomen: Does the mass move with the
liver during respiration? Is the liver parenchyma normal or