PAEDS 203 - Puberty and Adolescence Flashcards
What is consonance (in puberty)?
Smooth ordered progression of changes that happen throughout puberty in a somewhat uniform way
What does non-consonance in puberty suggest?
Over-activity of the sex hormones peripherally and usually present with virilizartion
What age does puberty occur in males and females?
males 10-11
females 8-9
How does puberty start?
Pulsatile release of GnRH which stimulates LH and FSH secretion from the anterior pituitary
What actions does LH have in the male and female?
Male: acts on Leydig cells to stimulate testosterone production
Female: acts on Theca cells to stimulate androgen production
What actions does FSH have in the male and female?
Male: stimulates Sertoli cells in the seminiferous tubules to produce mature spermatozoa
Female: stimulates follicular development and aromatase activity by acting on granulosa cells (therefore oestrogen production)
What are the main consequences of testosterone in male puberty?
Development of male secondary sexual characteristics : axilliary and pubic hair, enlargement of external genitalia, deepening voice, sebum secretion, muscle growth, libid and spermatogenesis
What are the main consequences of oestrogen in female puberty?
Breast and nipple development, vaginal and vulval growth, pubic hair, growth and maturation of uterus and fallopian tubes
What is the order of consonance for puberty in girls?
breast development, pubic hair, growth spurt, axillary hair
What is the order of consonance for puberty in boys?
Testicular/scrotal growth, pubic hair, growth spurt, increase in penis size, voice change, facial/axillary hair
How much do girls and boys grow approximately in puberty? What accounts for boys being taller than girls?
Boys 28cm Girls 25cm
Boys have an extra two years of growth as a child before puberty
What finishes bone growth?
Oestrogen causing fusion of epiphyseal plates
What defines delayed puberty?
Complete absence of physical signs of puberty after age 13 in girls and age 14 in boys
What are the two divisions that causes of delayed puberty can be split into?
Primary gonadal failure = hypergonadotrophic (high FSH and LH) and central failure = hypogonadotrophic (low FSH and LH)
What are some of the causes of primary gonadal failure ?
Turners syndrome Klinefelters syndrome Androgen insensitivity syndrome 5 alpha reductase deficiency Pelvic radiotherapy or chemotherapy
Describe Turners syndrome?
Often first manifestation in short stature and primary ammenorhoea - infertility or subfertility
Results from an XO chromosome but can have moasicism
Associated with diabetes, congenital heart defects, neck webbing and renal malformations
Describe Klinefelters syndrome?
XXY chromosomes and also have varying degrees of severity due to different mosaicisms.
Many men go undiagnosed until present with infertility later in life. In childhood there may be unusual rapid growth and failure of sexual maturation
Small firm tests and gynaecomastia
Treat with testosterone treatment during puberty
Describe androgen insensitivity syndrome
X linked recessive condition leading to failure of normal masculinization of the external genitalia in genetically male patient. Insufficient post receptor response after androgen stimulation. Can be complete or partial leading to a spectrum of presentations: infertility, gynaecomastia, vagina and clitoris or just clitomegaly or hypospadias
Describe 5 alpha reductase deficiency
AR sex limited condition
Inability to convert testosterone to DHT
therefore may be more with ambiguous genitalia and cryptorchidism
What are some of the causes of central failure in delayed puberty?
Constitutional Anorexia Excessive excersize Hypothyroidoism Intracranial tumour Isolated GH or GnRH deficiency
Define precocious puberty
Onset of secondary sexual characteristics in less than 8 in girls and less than 9 in boys
How do you manage precocious puberty?
Check bone age and pelvic structures (usually advanced by +2years)
MRI the pituitary
Treat with GnRH analogue until puberty should begin at about 11/12
What are the two divisions of classifying precocious puberty?
True central - gonadotrophin dependant
Peripheral - gonadotrophin independant
What are some of the causes of true central precocious puberty?
Most commonly idiopathic (more common in obese children and females) Tumours hydrocephalus chronic inflammatory disease Trauma, abuse or adoption
What tests distinguish between central, gonadotrophin dependant puberty and peripheral, gonadotrophin-independant puberty?
In central: LH and FSH and oestrogen are detectable and there is a positive response to the LHRH test
In peripheral: undetectable LH and FSH, with no LHRH response but detectable sex hormones
What are some of the causes of precocious puberty?
Ovarian cysts, cushings syndrome , adrenal tumours, congenital adrenal hyperplasia McCune albright syndrome Testotoxicosis
What is premature thelarche?
Early breast development but no other precocious features
What is exaggerated adrenarche?
Early pubic hair, body odour, mild acne but no other precocious features due to early adrenarche
Describe congenital adrenal hyperplasia
Group of AR disorders that involve an enzyme deficiency in the synthesis of cortisol and/or aldosterone
Clinical phenotype depends on enzyme deficiency and severity but females present with: virilisation, milder: early puberty
Males present normally but severe: salt wasting and failure to thrive, milder - early puberty
Treat symptoms and llong term glucocorticoid
Describe the presentation of McCune Albright Syndrome
Cafe au lait patches unilaterally, bone changes due to polyostotic fibrous dysplasia and often early puberty and hyperthyroidism (endocrine abnormalities)
Describe testotoxicosis
Actvating mutation of LHreceptor gene therefore increased sex steroids produced and decreased LH
What do bipotential gonads contain?
Both mullerian and wolffian ducts
What stimulates differentiation into male gonads?
Presence of SRY gene
What does the SRY protein stimulate?
Sertoli cells - produce AMH
Leydig cells - produce testosterone
What is the action of AMH?
Stimulates a wave of apoptosis causes the mullerian duct to regress and the wolffian duct to form the urinary tract and internal male genital structures
What causes external male genital formation?
DHT - converted in penile skin from testosterone via 5 alpha reductase
What happens in the absence of the SRY gene?
Mullerian ducts form uterine tubes, uterus and upper third of vagina and the lack of androgens allows the vagina, labia and clitoris to form
What is the mullerian duct also known as?
The paramesonephric duct
What is the wolffian duct also known as?
The mesonephric duct
