Puberty (normal and abnormal) Flashcards
What is puberty
The process of becoming sexually mature (fertile)
What is adolescence
The process of rapid physical and physiological maturation between childhood and adulthood
What are the non-pathological influences on the timing of puberty
Genetic: racial, familial, sex. Endocrine pathology: hypothalamo-pituitary, gonadal, adrenal. Environment: socioeconomic, secular trend, light and dark rhythms. Health linked to stress: emotional and physical. Drugs and body composition influence physical
What is menarche onset
Puberty starting
Who have earlier menarche
Those from urban areas and those from a higher socio-economic background
When do boys start puberty compared to girls
One year later
What is the normal puberty range for girls
8-18
When is girls peak growth
9-14
What is the normal puberty range for boys
10-15
What is boys peak growth
10-16
What is a prader orchidometer
It is used to assess testicular volume in young boys. When the beads become yellow it indicates the onset of puberty
Describe the Tanner stages of female development
5 stages of female breast and pubic hair development. Stages 3-4 are intermediate stages
Describe uterine volume between 0-8
Remains fairly constant between 2-1.5ml
Describe uterine volume between 8-14
Uterine volume increases to 40-14ml
What is ovarian volume from 0-5
0.4-1.0 ml
What is ovarian volume from 6-10
0.4-1.9 ml
By the time a girl reaches 16 what is her ovarian volume
1.8-22ml
How do ovaries change post puberty
from 0.6-6 ml
What regulates pubertal changes
Endocrine changes
In females what are aromatides (e.g. LH) converted to
Oestrogen
In men what is LH converted to
Testosterone and FSH used in sperm production
What do the phases of testicular function show
That post-natal boys go through a mini puberty
What effect does the gonadal feedback to the hypothalamic pulse generator have
A powerful inhibitory effect which prevents further production of LH and FSH
What happens to the inhibitory feedback loop at the onset of puberty
It is impaired
What is the gender difference in growth spurt
Girls grow fastest in their first few years of puberty. Girls pubertal peak is two years before boys
What is the relationship between growth hormone secretion and height velocity in puberty
The higher the mean 24-hour GH the greater the height velocity in cm/month
What is the effect of age on skeletal growth proportions
Growth doesn’t affect all parts of the skeleton equally
Describe the critical weight hypothesis
Different races have different critical weights at which menarche will occur. A minimum level of stored, easily mobilised energy is necessary for ovulation and menstrual cycle in girls. Having a minimum level of stored energy makes physiological sense as if you become pregnant it drains energy stores therefore you must have a store to become pregnant
What prevents the onset of pubertal development
Anorexia nervosa which is deliberate starvation
What does leptin stimulate
Reproductive axis (links nutritional store to puberty). Leptin has gonadal function
Describe congenital leptin deficiency
Normal birth weight, severe early onset obesity and hyperphagia, clincally and biochemically prepubertal aged 8 years, severely decreased serum leptin concentration, homozygous guanine nucleotide deletion of leptin gene
Describe the effect of congenital leptin deficiency on puberty
Homozygous misense mutation of leptin gene impaired mutant protein secretion. 34 yr old female- primary amenorrhoea. 22 yr old male- prepubertal, biochemical hypothalamic hypogonadism (very physiologically abnormal, means hypothalamic mediated hypogonadism)
What do mutations result in
Implications on the timings of the onset of puberty
What are the causes of delayed puberty
Constitutional delay- hypogonadotrophic hypogonadism, hypergonadotrophic hyopgonadism
Describe the causes of hypogonadontrophic hypogonadism
CNS disorders: tumours, other acquired disorders, congenital disorders. Isolated gonadotrophin deficiency. Multiple pituitary hormone deficiency. Others: Prader-Willi and Laurence-Moon-Bardet-Biedl syndromes, chronic disease, weight loss, anorexia, increased physical activity in females, hypothyroidism
Describe the causes of hypergonadotrophic hypogonadism
Klinefelter syndrome. Other forms of testicular failure, anorchia, cryptochidism. Turner syndrome, otehr forms of primary ovarian failure. XX & XY gonadal dysgenesis.
What is hypergonadism
A failure of feedback resulting in increased gonadotrophin levels
What is the effect of delayed puberty:
Relatively short stature, low self-esteem confidence and inadequacy, rejection, disturbed relationship with parents, attention seeking and immature behaviour, persistence of psychological features into adult life.
What does it mean if you have the correct height ages for bone age
You are normal and will achieve normal growth
What results in a greater peak height
Early onset of puberty
What is involves in treatment of delayed puberty
Investigations, reassurance, testosterone, ethinyloestradiol
What investigations would you do if indicated into delayed onset of puberty
Bone age, karyotype, gonadotrophins, sex steroids and LHRK usually helpful
Describe the use of testosterone in delayed puberty
Started from ages 14 years until testicular volume >8mls
What are the two different types of testosterone you can give
Sustanon (50-100mh monthly I/M). Testosterone undecanoate (40mg daily orally)
If there is no testicular enlargement despite virilisation what is required
Pituitary-gonadal testing
Describe ethinyloestradiol
5-10mg daily until puberty established
Do you use growth hormone in delayed onset puberty
No, no benefit
Describe how treatment for delayed onset puberty works
You give a low dose of testosterone to activate hypothalamic balance= GnRH= testosterone development. Testosterone is given as monthly injections. Sustanon is not very good as much is metabolised
What do you have to be careful with when someone has delayed onset puberty
You don’t miss an underlying pathology
How is oestrogen given to females
Orally
How is testosterone given to males
Via intramuscular injections
Describe Kallmann’s syndrome
Hypogonadotrophic, anosmia, usually X-linked, mutation in KAL 1 gene, olfactory hypo/agenesis. You have failure of pubertal development and no sense of smell (anosmia).
Describe Prader-Willi syndrome
Neonatal hypotonia and poor feeding, later hyperphagia and obesity, behavioural problems, poor growth, hypogonadotrophic hypogonadism, loss of paternal allele at 15q11-13 (loss of paternal allele on long arm of chromosome 15), possible benefit from GH therapy. Failure of GnRH production= hypogonadism.
Describe Turner’s syndrome
Missing/ major abnormality in X chromosome. Not all individuals have obvious features
Describe vanishing testes
Can’t find testes as they have undergone torsion after 1st trimester
What are the types of precocious puberty
Isolated breast development. Isolated pubic hair development and signs of androgen excess. Central precocious puberty. Gonadotrophin-independent precocious puberty. Other rare causes
Describe isolated breast development
Premanture thelarce
Describe isolated pubic hair development and signs of androgen excess
adrenarche, congenital adrenal hyperplasia- adrenal tumours
Describe central precocious puberty
Idiopathic, 2y to intracranial tumours
Describe gonadotrophin-independent precocious puberty
McCune-Albright syndrome, testotoxicosis
Describe other rare causes of precocious puberty
Hypothyroidism, gonadotrophin secreting tumours, exogenous steroids, rare syndromes e.g. Kabuki
Describe central precocious puberty
Cause of precocious puberty. Large tumour impairing feedback mechanism to prevent early onset puberty.
What are type 1 neuropathies
A cause of precocious puberty
Describe hypothalamic haematoma
A cause of precocious puberty. Activates hypothalamic pituitary axis
Describe congenital adrenal hyperplasia
A cause of precocious puberty. No oestrogen (excess androgen), no breasts
Describe ovarian granulosa cell tumour
A cause of precocious puberty. Large mass in pelvis, hormonally active so secretes oestrogen
Describe gonadotrophin-releasing hepatoblastoma
A cause of precocious puberty. Low pH, liber tumour, secreting hCG, hCG binds to LH receptor resulting in testicular growth
In boys what is often the underlying cause of precocious puberty
Something serious
How do you treat premature thelarche and adrenarche
No treatment
How do you treat secondary precocious puberty
Treat underlying condition (e.g. C.A.H, cerebral tumour etc.)
How do you treat gonadotrophin dependent precocious puberty
LHRH analogue (need to replace missing hormones)
How do you treat gonadotrophin independent precocious puberty
Anti-androgen (e.g. cyproterone, flutamide). Aromatase inhibior (e.g. tesolactone and spironolactone). Steroid biosynthesis inhibitor (e.g. ketoconazole). All harder to treat as not associated with gonasotrophin production. Possible use of growth hormone
