Puberty: advancements, delays, investigation and management Flashcards
Define puberty
Describes the physiological, morphological, and behavioural changes as the gonads switch from infantile to adult forms
What are the definitive signs of puberty in boys and girls?
- Girls: menarche - first menstrual bleeding
- Boys: first ejaculation, often nocturnal
- These do not signify fertility
What are the secondary sexual characteristics for girls?
Occur at puberty:
- Ovarian oestrogens regulate the growth of breast and female genitalia
- Ovarian and adrenal androgens control pubic and axillary hair
What are the secondary sexual characteristics for boys?
- Testicular androgens
- External genitalia and pubic hair growth
- enlargement of larynx and laryngeal muscles
→ voice deepening
What are Tanner stages?
A scale that defines physical measurements of development based on external primary and
secondary sex characteristics
Describe tanner stage 1 in boys
- Prepubertal: No pubic hair
- Testicular length <2.5 cm
- Testicular volume <3.0 mL
Describe tanner stage 2 in boys
- Sparse growth of slightly curly pubic hair, mainly base of penis
- Testes >3mL (>2.5cm in longest diameter)
- Scrotum thinning and reddening
Describe tanner stage 3 in boys
- Thicker, curlier hair spread to mons pubis
- Growth of penis in width and length; further growth of testes
Describe tanner stage 4 in boys
- Adult-type hair, not yet spread to medial surface of thighs
- Penis further enlarged; testes larger, darker scrotal skin colour
Describe tanner stage 5 in boys
- Adult-type hair spread to medial surface of thighs
- Genitalia adult size and shape
What instrument measures testicular volume in mL?
Orchidometer
Describe tanner stage 1 in girls
- Prepubertal: No pubic hair
- Elevation of papilla only
Describe tanner stage 2 in girls
- Sparse growth of long, straight or slightly curly, minimally pigmented hair, mainly on labia
- Breast bud noted/ palpable; enlargement of areola
Describe tanner stage 3 in girls
- Darker, coarser hair spreading over mons pubis
- Further enlargement of breast and areola, with no separation of contours
Describe tanner stage 4 in girls
- Thick adult-type hair, not yet spread to medial surface of thighs
- Projection of areola and papilla to form secondary mound above level of breast
Describe tanner stage 5 in girls
- Hair adult-type and distributed in classic inverse triangle
- Adult contour breast with projection of papilla only
What is thelarche?
breast development
- First visible change of puberty
What is thelarche induced by?
Oestrogen
How long does thelarche take?
Completed in about 3 years
What are the effects of oestrogen on the breast?
- Ductal proliferation
- Site specific adipose deposition
- Enlargement of the areola & nipple
What other hormones are involved with thelarche?
prolactin, glucocorticoids, insulin
What is precocious puberty?
onset of secondary sexual characteristics before 8 years (girls), 9 years (boys)
What might menarche before 9 years old lead to?
Short stature
Define delayed puberty
absence of secondary sexual characteristics by 14 years (girls), 16 years (boy)
What does delayed puberty lead to?
reduced peak bone mass and osteoporosis
What is adrenarche?
Maturational process of the adrenal gland
- Only observed in humans and in some old world primates
- Mild advanced bone age, axillary hair, oily skin, mild acne, body odour
What is pubarche?
- Most pronounced clinical result of adrenarche
- Result of androgen action on the pilosebaceous unit transforming vellus hair into terminal hair in hair-growth prone parts of the skin
What are indications for delayed puberty in girls?
- Lack of breast development by 13 yrs
- More than five years between breast development and menarche
- Lack of pubic hair by age 14 yrs
- Absent menarche by age 15-16 yrs
What are indications for delayed puberty in boys?
- Lack of testicular enlargement by age 14 yrs
- Lack of pubic hair by age 15 yrs
- More than 5 years to complete genital enlargement
What laboratory investigations would you to investigate delayed puberty?
- Complete red blood count
- U + E, renal, LFT
- LH, FSH
- Testosterone/ oestradiol
- Low concentrations of this and LH/ FSH can be seen during quiescent phase and early puberty
- Thyroid function, prolactin
- DHEA-S, ACTH, Cortisol
When would karyotyping be needed?
In ALL girls with short stature
What are the functional causes of delayed puberty?
- Chronic renal disease
- Chronic lung disease
- Anorexia nervosa
- Psychosocial/ stress
- Drugs
What happens in primary hypogonadism in females?
In ovaries
● Oestrogen goes down
● Lack of feedback
● LH and FSH increase
What happens in primary hypogonadism in males?
In testes
● Testosterone goes down
● Lack of feedback
● LH and FSH increase
What happens in secondary hypogonadism in females?
In hypothalamus and pituitary
● LH and FSH low
● No response to feedback
● Oestrogen decreases
What happens in secondary hypogonadism in males?
In hypothalamus and pituitary
● LH and FSH low
● No response to feedback
● Testosterone decreases
What is Klinefelter syndrome?
Primary hypogonadism
47, XXY
What is Turner syndrome?
45, X0 girls
What is seen in Turner syndrome?
- Renal malformations – horseshoe kidney (fusion of the kidney)
- Short stature
- Cardiovascular malformations – aortic arch, spontaneous rupture
What is the incidence of Turner syndrome?
1 in 2000 girls
