Diagnostic ultrasound ( PDFDrive )

1824 PART V Pediatric Sonography
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B
FIG. 52.71 Normal Neonatal Adrenal Gland. (A) and (B) Longitudinal and transverse gray-scale images of the right adrenal gland show a
Y-shaped coniguration with a hypoechoic rim representing the fetal adrenal cortex and a central echogenic adrenal medulla. +, Length; *, width;
x, thickness.
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B
FIG. 52.72 Congenital Adrenal Hyperplasia. Neonate With Ambiguous Genitalia. (A) and (B) Transverse images of the right and left
adrenals, respectively, reveal enlarged glands with a cerebriform appearance (arrows).
CAH causes bilateral adrenal gland enlargement, which may
be asymmetrical. An adrenal gland limb thicker than 4 mm is
considered enlarged, even in the neonatal period. 219 However,
adrenal gland enlargement alone is not sensitive or speciic for
the diagnosis of CAH. A normal-sized adrenal gland does not
exclude the diagnosis of CAH, and some healthy babies have
adrenal glands in the size range typical of CAH. 219 Speciic features
in the evaluation of the adrenal glands can make ultrasound a
sensitive and speciic presumptive test for CAH pending the
results of laboratory studies. hese include a cerebriform appearance
of the gland 220 (Fig. 52.72) and stippled echoes, or difusely
increased central glandular echogenicity 221 rather than the normal
central echogenic stripe. Pelvic sonography is extremely valuable
in the evaluation of female infants with suspected CAH and if
there are ambiguous genitalia. Although the external genitalia
are masculinized, the internal female genitalia are present. In
neonates, the presence of the uterus is exceptionally well demonstrated
because of the normal maternal hormones that stimulate
development of a prominent echogenic endometrial stripe in
the uterine cavity.
Testicular adrenal rest tumors are very common, particularly
in postpubertal boys with poorly controlled congenital adrenal
hyperplasia. hese tumors are small, generally multiple, and
oten bilateral. he involved testis may be enlarged, but its contour
is not distorted. he masses are eccentric and commonly surround
the mediastinum testis. 222,223
Neonatal Adrenal Hemorrhage
Hemorrhage into the adrenal gland occurs in the neonate and
may even start in utero. It is associated with fetal macrosomia,
fetal acidemia, stress, birth trauma, asphyxia, sepsis, bleeding
disorders, and maternal diabetes. 224 It occurs most frequently
between the second and seventh day of life, with an abdominal
mass, hyperbilirubinemia, and occasionally, hypovolemic shock.
In some cases, the hemorrhage is asymptomatic and may be
discovered incidentally or appear as a palpable mass. About 70%
of adrenal hemorrhages are right-sided. 225 Sonography demonstrates
a suprarenal mass of variable echogenicity, depending on
the age of the bleed. Acute hemorrhage usually appears echogenic
or isoechoic to the normal gland, without internal vascularity