pediatric ultrasound

hypertrophic pyloric stenosis (HPS)

a defect of the relaxation of the pyloric sphincter that leads to hypertrophy of the pyloric muscles, effectively causing a persistent closure of the pyloric sphincter

HPS can occur in adults but it is most commonly encountered in:

• infants between 2 and 8 weeks old

• first born males are more likely to suffer from this

clinical symptoms of HPS:

• non-bilious projectile vomiting

• dehydration

• weight loss

• constipation

• insatiable appetite

• enlarged pyloric muscle that may be palpable on an infant (“olive” sign)

sonographic appearance of HPS:

• infant placed in RLD

• if stomach empty, water or glucose given to visualize pylorus better

• in longitudinal plane, pylorus seen within epigastrium, slightly right of the midline, near the GB

• appears as a “target” or “doughnut” in the transverse plane and as a cervix (cervix sign) in the sag plane

pylorospasm

a common cause of delayed gastric opening

sonographic appearance of pylorospasm:

• measurements tend to be within normal range

• some fluid should be noted traveling through the pyloric channel

diagnostic criteria of HPS:

• pyloric muscle greater than or equal to 4 mm n thickness

• length of abnormal pyloric channel is greater than or equal to 17 mm

• pyloric cross section is more than 15 mm

malrotation of the midgut

the small bowel mesentery rotates around the superior mesenteric artery

sonographic appearance of malrotation of the midgut:

• confirmed by identifying the relationship of the SMA to the SMV

• normally, SMA located to the left of SMV and with malrotation, the vessels will be reveresed

intussusception

telescoping of one segment of the bowel into another

what is the most common acute abdominal disorder in early childhood?

intussusception

clinical symptoms of intussusception:

• severe abdominal pain

• vomiting

• palpable abdominalmass

• stool contains a mixture of blood and mucus (red currant jelly stool)

• leukocytosis

• can lead to ischemia and gangrene of the bowel

• occurs more often in males

• most common case of intestinal obstruction in children less than 2 yrs of age

sonographic appearance of intussusception:

• appears as a “target” mass in the transverse plane

• appears as a “pseudokidney” in the sag plane

• will have alternating rigs of echogenicity representing the edematous layers of the bowel wall

• abnormal bowel wall in this area will be non-compressible

Wilm’s tumor (nephroblastoma)

• typically discovered before age 5

• can grow reasonably large before discovery and can invade the renal vein and IVC

• tend to spread to liver and lungs

clinical symptoms of a Wilm’s tumor:

• palpable abdominal mass

• abdominal pain

• hematuria

• fever

• HTN

pediatric pts with what disease have a tendency to develop a Wilm’s tumor?

pts with Beckwith-Wiedmann syndrome

sonographic appearance of a Wilm’s tumor:

appears as a large solid mostly echogenic mass that contains anechoic or hypoechoic regions

posterior urethral valve obstruction (PUV)

• the presence of a valve in the posterior urethra

• occurs only in male fetuses

• common cause of bladder outlet obstruction

sonographic appearance of PUV:

• hydronephrosis

• hydroureters

• dilation of the bladder

• bladder wall is severely thickened with a dilated posterior urethra (“keyhole” sign)

multicystic dysplastic kidney disease (MCDK)

• most common cause of an abdominal mass in newborns

• typically unilateral but can be bilateral which is fatal

sonographic appearance of MCDK:

• non-communicating cysts with the absence of renal parenchyma

• no identifiable renal sinus

hepatoblastoma

• most common malignant liver tumor in early childhood

• most occurrences are prior to 2 yrs of age

• high incidence in children with Beckwith-Wiedemann syndrome

clinical symptoms of hepatoblastoma:

• large asymptomatic abdominal mass

• increased levels of serum alpha fetoprotein

sonographic appearance of hepatoblastoma:

• solid, hyperechoic or heterogenous mass

• may contain calcifications

biliary atresia

• congenital disease

• narrowing or obliteration of all or a portion of the biliary tree

• eventually infants suffer from cirrhosis and portal HTN

sonographic appearance of biliary atresia:

• absent biliary ducts

• GB may be absent

choledochal cyst

• 5 different types

• most common type is cystic or fusiform dilatation of the CBD

• usually discovered in infancy or 1st decade of life

clinical symptoms of a choledochal cyst:

• abdominal mass

• jaundice

• pain

• fever

sonographic appearance of a choledochal cyst:

fusiform cystic mass in the area of the porta hepatic and biliary dilatation

Caroli’s disease

congenital disorder characterized by segmental dilatation of the intrahepatic ducts

sonographic appearance of Caroli’s disease

multiple cystic structures communicating with the bile ducts