W8 - Puberty Flashcards
what is the definition of puberty
the physiological, morphological, and behavioural changes as the gonads switch from infantile to adult forms.
what is the definition of the first period a girl has
Menarche
what is the definitive sign of puberty in boys
first ejaculation - often nocturnal
what 2 hormones are increased at the start of the puberty pathway
FSH and LH
what tests would you do to investigate puberty
Pubertal Staging
FSH, LH, Testosterone, Oestradiol, Prolactin, thyroid function, karyotype, Androstenedione, DHEAS
GnRH Test
Bone Age X-ray (dominant hand & wrist)
Pelvic Ultrasound (girls)
how much later do boys experience their growth spurt
2 years later than girls
what determines the timing of puberty in children
genetics
nutrition
environment
what percentage of body fat is needed for menses
17
what percentage body fat is needed for ovulation
22
what environments cause an earlier puberty
urban area
close to the equator
lower altitude
what do ovarian oestrogens for in girls
regulate the growth of breast and female genitalia
what do ovarian and adrenal androgens for in girls
control pubic and axillary hair
what do testicular androgens do in boys
External genitalia and pubic hair growth
enlargement of larynx and laryngeal muscles - voice deepening
what features are first to occur in puberty in boys
testicular enlargement and pubic hair growth
when does growth of penis and heigh start
12 months after first start of puberty
what is the average age of menarche
13yrs
earlier in ethnic minorities
does early puberty result in longer puberty
no
early start, early stop
does a late start to puberty mean a late end to puberty
no
more limb growth - are not as tall as expected
what is the pathway for FSH and LH release (HPA axis)
who and why do some people go into puberty early
Usually girls
Usually idiopathic
CNS lesion may be present
what is the aetiology of premature thelarche
isolated breast development
typically very young girls age 1-4y.
Non-progressive, with no growth spurt.
Remits spontaneously.
what is the aetiology of Premature Pubarche (Adrenarche)
isolated pubic hair development. Usually girls around 5-7y.
what is the aetiology of Isolated Premature Menarche
early onset of periods, despite no, or minimal pubertal development
Exclude hypothyroidism
what is the aetiology of Isolated Adolescent Gynaecomastia
common in early to mid-puberty in boys, particularly if obese
what is the main cause of central precocious puberty in girls
idiopathic 95%
what is central precocious puberty
Congruent breast and pubic hair development
Puberty earlier in obese children
Associated growth spurt (if short, exclude hypothyroidism)
Mood swings
Final height may be impaired
Pelvic Ultrasound very helpful
what would you use the GnRH (LHRH) Test for
to differentiate between true precocious puberty and precocious pseudo-puberty
what is the most common cause of central precocious puberty in boys
CNS lesion
ALWAYS pathological
what is central precocious puberty in boys
Congruent penis and pubic hair development
Testicular volumes increased
Sexualised behaviour
Associated growth spurt
Mood swings
Final height may be impaired
what are some differential causes of true central precocious puberty (GnRH dependent)
Idiopathic precocious puberty
CNS tumors
Optic glioma associated with NF1
Hypothalamic astrocytoma
CNS disorders
Developmental abnormalities, hypothalamic harmartoma
Encephalitis, Brain abscess
Hydrocephalus, Myelomeningocele, Arachnoid cyst
Vascular lesion
Cranial irradiation
Secondary central precocious puberty
Psychosocial, i.e. adoption from abroad
what are some differential causes of pseudo-precocious puberty (GnRH independent)
Increased androgen secretion
Gonadotropin secreting tumours
McCune-Albright syndrome
Ovarian cyst
Oestrogen secreting neoplasm
(Hypothyroidism)
Iatrogenic or exogenous sex hormones
what are some causes of autonomous pseudo-precocious puberty (GnRH independent)
McCune-Albright Syndrome
Hormone-Secreting Tumours
Autonomous testosterone production (Testotoxicosis)
Congenital Adrenal Hyperplasia (boys)
what hormone changes would you see in pseudo-precocious puberty (GnRH independent)
High oestradiol or testosterone, with suppressed gonadotrophins.
what is McCune-Albright Syndrome
precocious puberty,
large irregular café-au-lait polyostotic fibrous dysplasia
what kinds of tumours can cause pseudo puberty
Gonadal tumours
Adrenal tumours
Embryonal tumours
Rarely, hCG or TSH secreting tumours
what is congenital adrenal hyperplasia
Inborn error of cortisol +/- aldosterone synthesis
> 95% 21a-hydroxylase deficiency
Large amounts of adrenal androgens and testosterone secreted, producing virilisation, but with small testes
what is the treatment for congenital adrenal hyperplasia
hydrocortisone replacement
what is the treatment for central precocious puberty
GnRH analogues
what is the treatment for Gonadotrophin independent precocious puberty
Treat underlying cause
Anti-androgens/androgen receptor blockers/aromatase inhibitors
what are some common causes of delayed puberty
Constitutional delay in growth & adolescence
Illness/malnutrition
Failure of Hypothalamus/pituitary
Gonadal failure
what is the common signs and symptoms of consitutional delay
Often familial
Much more common in males (M:F 5:1)
Associated short stature
Spontaneous puberty will occur
Relative disproportion
Reduced final height
what illnesses can result in delayed puberty
Cystic fibrosis
Crohn’s disease
Juvenile arthritis
Steroid therapy
Hypothalamic amenorrhoea
- Anorexia Nervosa
- Athletes/gymnasts
- Due to leptin deficiency
what is Hypogonadotrophic
Hypogonadism
Hypothalamic GnRH deficiency with Anosmia
Kallman’s Syndrome
what are the characteristic features of kallmans syndrome
Normal stature
Eunuchoid habitus
Long limbs
Female body shape
what sex disturbance would be present in Prader Willi syndrome
Hypogonadotrophic Hypogonadism
what are the characteristic features of prader-willi syndrome
Disordered hypothalamic function
Short stature
Voracious appetite
Learning difficulties
Characteristic appearance
Loss of paternal 15q11
what would you see in Pituitary Gonadotrophin deficiency
Hypogonadotrophic Hypogonadism
Short stature and other features of hypopituitarism if associated with pituitary pathology
May be isolated
what sex hormone disfunction is caused in kleinfelters syndrome
Gonadal Failure
(47 XXY)
what are the features of kleinfelters syndrome
Often mild developmental delay/autistic features
Small, hard testes
Gynaecomastia (breast ca)
Elevated FSH, LH, low testosterone
what are the features of turners syndrome
Gonadal failure
Characteristic appearance
Short stature
Cardiac, renal anomalies, glue ear
Elevated FSH, LH, low oestradiol
