Puberty

Terminology: adrenarche — activation of the adrenal gland; gonadarche — activation of the gonads; thelarche — breast tissue development; pubarche — pubic hair. Central (gonadotropin-dependent) vs peripheral (gonadotropin-independent) puberty.

First signs: males — testicular enlargement to 4 mL; females — breast buds.

Normal onset: females 8–13 years (breast budding); males 9–14 years (testicular enlargement). There is a trend to earlier breast development in girls (though menarche is not occurring earlier) and a slight decline in onset age in boys, but the age limits for precocious puberty have not been lowered.

Precocious puberty

• Breast development before 8 years, or testicular enlargement >4 mL before 9 years; also body odour, skin oiliness, pubarche.
• More common in girls; organic pathology is more likely in boys.
• Ask about neurological symptoms, abdominal pain, and exogenous hormone exposure (mum on HRT, dad on testosterone, antipsychotics).

Investigations: bone-age X-ray is very helpful (may be the only test needed before referral); consider LH, FSH, oestradiol, testosterone, DHEAS, ±17-OHP, TSH; pelvic/testicular ultrasound; MRI brain in all males and in females <6 years.

Variants:

• Premature thelarche — isolated breast development in a 2–3-year-old with no other pubertal signs; follow up for growth acceleration (can occasionally progress to precocious puberty).
• Premature adrenarche — early pubic/axillary hair, skin oiliness, acne, body odour from increased adrenal hormone production.

Consequences: loss of adult height (early growth-plate fusion); psychosocial issues.

Treatment: GnRH analogues (leuprorelin, triptorelin) — bind and down-regulate the receptors. Clear benefit ≤6 years; less clear in girls 6–8; reasonable to treat boys.

Delayed puberty

Absence of clinical signs of puberty by 13 years in girls and 14 years in boys.

• Hypogonadotrophic hypogonadism — constitutional delay, functional, or permanent (e.g. Kallmann syndrome).
• Hypergonadotrophic hypogonadism — high FSH/LH, low oestradiol/testosterone (e.g. Klinefelter syndrome).

Investigations: bone-age X-ray; FSH/LH, oestradiol, testosterone.

Pubertal gynaecomastia

Occurs in 50–60% of boys (peripheral conversion of testosterone to oestrogen). Typically resolves within 12 months; >4 cm and bilateral is more concerning. Refer if persisting past age 17.