A 3650-g term infant has ambiguous genitalia, including an enlarged clitoris
or microphallus and one palpable testis in the labioscrotal folds. Sonogram
reveals a uterus and ovaries. Which of the following is the most likely explanation for the child’s ambiguous genitalia?
A. Aromatase deficiency
B. Congenital adrenal hyperplasia
C. Female pseudohermaphroditism
D. Male pseudohermaphroditism
E. True hermaphroditism
5.2 A mother brings in her 1-week-old son who has vomited four times over the
last 24 hours. He has no fever or diarrhea. The infant is breast-feeding poorly
and is “floppy” per the mother. He has had only one wet diaper in the last
12 hours. Physical examination reveals a lethargic infant who has lost 250 g
since birth, with pulse of 110 beats/min, dry oral mucosa, and no skin turgor. You suspect a form of adrenogenital syndrome precipitating salt wasting.
Which of the following serum levels should be checked after hemodynamic
stabilization and electrolyte measurement?
A. Cortisol
B. Pregnenolone
C. ACTH
D. 17-hydroxyprogesterone
E. Testosterone
ANS:
5.1 E. The gonad in the labioscrotal fold suggests a testis, but a uterus and an ovary
on sonography are highly suggestive of a true hermaphrodite. Gender assignment in this case should be based on the possibility of surgical correction of
the external genitalia. Assignment of female sex and an attempt to preserve
ovarian tissue is appropriate.
5.2 D. Male infants with salt-losing CAH develop clinical symptoms similar to
pyloric stenosis, intestinal obstruction, heart disease, cow’s milk intolerance,
and other causes of failure to thrive. Their genitalia appear normal. A serum
17-hydroxyprogesterone level typically is elevated and is the first enzymatic
assay considered when CAH is suspected. Without appropriate treatment
(hydrocortisone, mineralocorticoid, and sodium supplementation), cardiovascular collapse and death may occur within a few weeks. Many states have
neonatal screening programs for CAH, yet infants with salt-losing CAH
(21-hydroxylase deficiency) can become very ill and die before the screening
results are known.