A mixture of topics this month again. Estimating testicular volume without an orchidometer, correcting for gestational age on growth charts, Resus Council update and the ins and outs of using photographs in virtual consultations. Do leave comments below.
Local anaesthetic cream this month (why do some places not use it in the under 1’s?), a link to useful “flash card” learning in the paediatric ED from Leicester, new Movicol doses, diphtheria and the last instalment of urinalysis with bilirubin and urobilinogen. A reminder also to please discuss children with glycosuria and a high BM with a paediatrician – most children have type 1 diabetes and are at risk of DKA at diagnosis. Do leave comments below:
With thanks to Dr Amy Rogers for unravelling endocrinology for the better understanding of all non-endocrinologists. All girls under 8 and boys under 9 with signs of puberty should be referred to a paediatrician and you could leave it at that. But for those who want to know a bit more about it (or check up on what we do about it…) read on!
The British Society of Paediatric Endocrinology and Diabetes (BPSED) is recognised by the Royal College of Paediatrics and Child Health (RCPCH) as the society responsible for this field of paediatric medicine. It is currently chaired by Professor Dattani of Great Ormond Street Hospital and represents the only U.K. society responsible for governing the training of doctors in paediatric endocrinology and diabetes and actively supporting the ongoing training and education of allied healthcare professionals in this specialist area. Lots of resources available at www.bsped.org.uk
The hormones of puberty: Hypothalamic-Pituitary-Gonadal Axis:
Start of puberty in girls = palpable breast bud (B2)
Start of puberty in boys = testicular vol >3.5ml
Androgens promote other secondary sexual characteristics: smelly feet, acne, body odour and mood swings!
Timing of puberty is dependent on socioeconomic status, nutritional and genetic factors.
In the UK early puberty = <8years girls, <9 years boys. Interpret in conjunction with family history (age of maternal puberty), ethnicity (Afro-Caribbean or mixed race = commoner to have early menarche), BMI (overweight = associated with early puberty), social factors (adoption and lower SEC = early puberty) and past medical events. Approx 10% girls achieve menarche whilst still in primary school.
RED FLAG: ARRESTED PUBERTY = SERIOUS PATHOLOGY
Pubertal development may be:
1) Concordant (following the normal pattern), i.e. breast buds, pubic hair then menses/increased testicular vol, pubic hair then penile enlargement).
2) Discordant, e.g. progressive breast enlargement with no pubic hair, or penile enlargement with small testicles. Suggests over activity of sex hormone (oestrogen/testosterone) production in the periphery, i.e. adrenals, gonads (ovaries/testes) or tumours.
Causes of precocious puberty
Central precocious puberty (gonadotrophin dependent)
- Idiopathic = Most common cause in girls (10 times more common than boys). Slowly progressing (breast and pubic hair growth, modest growth spurt, bone age advanced <1yr, few changes on pelvic USS) or more aggressive (height velocity greater, bone age advanced >1 yr). Ovarian and uterine enlargement (>2ml) on USS. Pubertal response to stimulation test. Boys: testicular enlargement, virilisation, pubertal response to stimulation test.
- Tumour = Second most common cause in both sexes (at least half of all boys presenting with central precocious puberty), typically a hypothalamic hamartoma
- Optic glioma (NF)
- Longstanding/severe peripheral secretion
- Abnormal brain (hydrocephalus, septo-optic dysplasia)
- CNS damage (infection/trauma/ low dose irradiation)
- HCG production (CNS or peripheral tumours)
Peripheral precocious puberty (gonadotrophin independent): peripheral oestrogen
Ovary tumour or cyst (including McCune-Albright syndrome and massive ovarian oedema)
Peripheral precocious puberty (gonadotrophin independent): peripheral androgen
Atypical congenital adrenal hyperplasia (CAH)
Adrenal tumour (including Cushing’s)
Testotoxicosis (male limited family history) and McCune-Albright syndrome (irregular café-au-lait patches, bony changes on xray and ovarian cysts (that may be huge).
Examination alone is often enough to determine if this is “true” puberty or just early thelarche (breast development) or pubarche (body hair), especially if combined with bone age.
- X-ray right wrist (bone age)
- Pelvic and abdominal USS (looking for tumours, cysts, size and position of gonads/internal genitalia)
Definitive test for central precocious puberty = GnRH stimulation test:
1) Measure LH, FSH, oestrogen/testosterone at base-line.
2) Give GnRH and monitor serial response of LH and FSH (20mins and 60mins)
|LH/FSH||↑||↓||Central precocious puberty|
|LH/FSH||↓||↓||Peripheral precocious puberty|
MRI hypothalamus, pituitary and brain in aggressive forms of early puberty, in girls less than 6 years of age, any child with neurological signs, and all boys.
Other tests to consider:
- TFTs (elevated TSH in hypothyroidism can mimic FSH, inducing early testicular and ovarian enlargement)
- Tumour markers (HCG can be produced from pineal, hepatic and testicular tumours) and alpha fetoprotein will be raised but LH/FSH will be low and non-stimulatable.
- Testosterone, oestrogen, morning LH/FSH
1) Early thelarche or pubarche: None. However, if pubarche associated with being overweight in girls, important to control weight, otherwise at increased risk of polycystic ovary syndrome (PCOS) and Type 2 diabetes later in life.
2) Supportive, let nature take its course: coping with periods, behavioural and cosmetic changes. School need to be aware.
3) Triptorelin or Goserelin injection = long acting GnRH analogues (given every 4-12 weeks depending on preparation used and body’s response to it). Will slow down or stop development. Continued until child’s peers are entering puberty, typically aged 10-11years. GH in addition, may result in improved final height, in girls.
Additional notes on discordant sexual development:
Thelarche: commonly present from infancy, non-progressive, may be unilateral. No treatment required.
Ovarian (and adrenal, testicle or liver) tumours secreting oestrogen are rare and often present with a palpable mass and prominent breast development with no other signs of puberty.
Thelarche-like symptoms are produced from oestrogen containing medications.
Adrenal androgens are the commonest cause of early virilisation leading to sexual hair growth, body odour, acne, greasy hair and mood swings.
Adrenarche = normal maturation of the adrenal glands leading to enhanced secretion of the androgen DHEA. Usually co-existent with the onset of normal puberty and contributes most of the androgenic component of puberty in young females. Premature adrenarche may be familial, spontaneous, or with an ill-understood association with hydrocephalus. No treatment required. A proportion of girls affected will proceed to PCOS, especially if they gain excessive weight.
Atypical CAH (mild, non-salt wasting type) mimics adrenarche and can be easily differentiated by a urinary steroid profile or a short Synacthen test and measurement of 17 alpha hydroxyprogesterone. A pubertal response to stimulation testing will require treatment with both hydrocortisone and GnRH agonists to achieve a reasonable final height.
Non-iatrogenic Cushing’s syndrome tends to be accompanied by excess adrenal androgen secretion and hirsuitism.
Isolated premature menarche is relatively common disorder of unknown aetiology. USS demonstrates prepubertal uterus with no endometrial lining between bleeds. Differential diagnosis includes rare local lesions, e.g. sarcoma, abuse and vaginal foreign body.
Mild, transient breast enlargement occurs in approx 50% boys in early puberty, but severe persistent gynaecomastia is increasingly common, possibly secondary to nutritional excess or environmental chemicals. Usually accompanies early puberty but can be pre-pubertal. Investigations for ectopic oestrogen secretion, karyotype, liver and thyroid function are usually normal. If present for >18m, may require surgical removal. If diagnosed early, treatment with anti-oestrogen medication such as anastrozole may have some benefit.