Chapter 41 Gynaecological problems in childhood and adolescence
INTERSEX
The first question a mother asks after her baby has been born is ‘Is it a boy or a girl?’ The answer is given after looking at the infant’s genitals, but in two neonates out of 10 000 the genital sex is ambiguous and the child is judged as being intersex.
Most neonates with ambiguous genitals are genetically female and have congenital adrenal hyperplasia. A few have an adrenal tumour or drug-induced virilism. In rare cases the neonate is a hermaphrodite, having a testis, an ovary and ambiguous external genitals.
Congenital adrenal hyperplasia (CAH)
This condition affects one in 10 000 neonates and is due to a group of enzyme defects which prevent the synthesis of cortisone from progesterone. The lack of circulating cortisone permits the hypothalamus–pituitary to release quantities of corticotrophins, which stimulate the adrenal gland to secrete androgens, with resulting virilization of the external genitals (Fig. 41.1).
The most common enzyme defect is C21-hydroxylase deficiency (found in more than 90% of cases). In three-quarters of cases ambiguous external genitals are the only sign of the condition, but in a quarter of cases aldosterone production is lost and the patient has a salt-losing syndrome.
Any child with ambiguous genitals should be investigated for CAH, by determining the chromosomal sex and by measuring the 17-hydroxyprogesterone level (a level of more than 7 mmol/L confirming the diagnosis) and checking the serum electrolytes. Treatment should be effected urgently or death may supervene from salt loss. The infant is treated with cortisone or one of its derivatives and careful follow-up is essential, but surgical correction of the external genitals should be delayed for 3–4 years.
Other causes of intersex
Other varieties of intersexuality are not diagnosed until after puberty, when menstruation fails to start. They include gonadal dysgenesis (Turner’s syndrome), testicular feminization (androgen insensitivity syndrome) and Klinefelter’s syndrome (seminiferous tubular dysgenesis).
Gonadal dysgenesis
There are two varieties of this condition, pure gonadal dysgenesis and Turner’s syndrome.
Pure gonadal dysgenesis
In this disorder, genital hypoplasia is detected in a girl who has normal breast development. A chromosomal analysis shows a mosaic 46, XO/XX.
Gonadal dysgenesis/Turner’s syndrome
Turner’s syndrome is caused by the deletion of some or all of the genes on the X chromosome. The classic Turner’s syndrome karyotype is 45, X, but the majority have a mosaic pattern with a normal second cell line (e.g. 45, X/46, XX or 45, X/46, XY). The incidence is between 1/2000 and 1/5000 in liveborn infants (99% do not survive to term).
In adolescence the classic features are short stature and arrested or delayed puberty (Fig. 41.2
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