Case 15- Puberty and SAP Flashcards
What is included in Tanner staging
Classification system that tracks the order of development of the secondary sexual characteristics in puberty:
- Male external genitalia (penis, scrotum, testicular volume)
- Female breast development
- Male and female pubic hair
Tanner staging- male external genitalia
1) Stage 1- testes less than 2.5cm
2) Stage 2- scrotum and testes enlarge and reddening of scrotal skin
3) Stage 3-continued growth of penis and testes
4) Stage 4- development of the glans, continued growth and scrotal skin darkens
5) Stage 5- adult genitalia size morphology
Testicular growth- enlargement of seminiferous tubules, epididymis and seminal vesicles and prostate increase in size
Tanner staging- female breast development
Stage 1- prepubertal, elevation of papilla only
Stage 2- areola enlarges and breast bud appears
Stage 3- breast tissue grows beyond areola but without contour separation
Stage 4- Projection of areola and papilla forms a second mound
Stage 5- adult breast contour with projection of papillar only
Tanner staging- Pubic hair development (men)
Stage 1- Villus hair only
Stage 2- Sparse hair along base of penis
Stage 3- Thicker hair, spreads to mons pubis
Stage 4- adult pattern but without spread to medial thigh
Stage 5- adult spread to medial thigh but not linea alba
Tanner staging- pubic hair (female)
Stage 1- Villus hair only
Stage 2- Sparse hair along labia
Stage 3- Hair coarse and pigmented, spreads across pubes
Stage 4- adult pattern but without spread to medial thigh
Stage 5- adult spread to medial thigh but not linea alba
Physical growth in adolescents
Growth spurt begins- 10.5 years in girls and 12.5 years in boys
Reach full adult height- 17 years in girls and 21 years in boys
Cause of growth spurt
Testosterone is converted to oestradiol causing increased release of GH from the anterior pituitary gland. GH increases anabolic hormone IGF-1 which causes somatic growth via metabolic actions i.e. an increase in trabecular bone growth. In males the larynx and vocal cords enlarge and the voice deepens in pitch.
Female timeline puberty
10.5 years- breast bud forms 11 years- pubic and axillary hair develops 11.5 years- growth spurt 13 years- menarche 13.5 years- adult pubic hair 14.5 years- adult breast
Boys puberty timeline
11.5 years- testicular enlargement
12 years- pubic and axillary hair develops
12.5 years- growth spurt
13.5 years- spermarche, nocturnal emissions begin
15 years- adult penis and testicular size
Early 20’s- adult pubic hair
GnRH and puberty
The Hypothalamus releases GnRH in a pulsatile manner, stimulating the release of FSH and LH from the anterior pituitary. FSH and LH act on the gonads to cause sex steroid hormone production and support gametogenesis. The sex steroids provide negative feedback on the hypothalamus and pituitary to keep circulating levels stable.
FSH and LH- puberty
A year before the start of puberty there is an increase in FSH and LH release. The rise in FSH stimulates an increase in oestrogen synthesis and oogenesis in females and sperm production in males. The rise in LH stimulates an increase in the production of progesterone in females and an increase in testosterone production in males.
The two hypothesis for the start of puberty
The rise in GnRH causes the onset of puberty. The two hypothesis for this are:
1) The brake release hypothesis
2) The accelerator hypothesis
Puberty- the break release hypothesis
Timed disinhibition of the inhibitory mechanisms. At the start of puberty the negative threshold of the hypothalamus to oestrogen and progesterone increases. Higher levels of oestrogen and progesterone are now needed to inhibit GnRH secretion. As the hypothalamus threshold increases (the brakes are released), the original low levels of oestrogen and progesterone cannot inhibit GnRH secretion - so FSH and LH levels rise = so higher levels of oestrogen and progesterone are secreted. Same in males but with testosterone.
Puberty- the accelerator hypothesis
Most widely accepted. The increase in permissive signals which kick start puberty. Leading up to puberty there in maturation of the CNS and activation of the Hypothalamic stimulatory centres. Upon CNS maturation, there is an induction of the pulsatile GnRH generator which leads to the increased secretion of LH and FSH. There is neuronal maturation and activation of the GnRH pulse generator. Same in males but with testosterone
Factors that affect age of menarche
- Genetics- link with maternal menarche age, genes (Kiss1)
- Metabolism and nutrition
- General health and wellbeing
- Family history of early or delayed puberty or genetic disease
- Previous growth and development
- Medical history
What weight does menarche start at
Menarche starts earlier with an increased BMI. Critical weight of 47kg must be achieved before activation of the hypothalamo-pituitary gonadal axis. A critical body weight and fat are required for the initiation of menarche.
The nutritional effects of menarche
- Leptin- adipocyte derived hormone which has permissive effect on menarche
- Insulin- modulates GnRH either directly/indirectly
Criteria for delayed puberty
- In boys- the absence of testicular development, or testicular volume less than 4ml by 14
- In girls- the absence of breast development by 13, or primary amenorrhoea with normal breast development by 15.
How common are eating disorders
Binge eating disorder is the most prevailent eating disorder and is more common in women then men. Women are more likely to have an eating disorder then men. Bullimia is more common then anorexia nervosa.
Weight and eating disorders
People with anorexia are by definition under weight, those with bulimia tend to be of normal weight and those with binge eating disorder are overweight.
The diagnostic criteria for anorexia nervosa
- Lower energy intake than needed causing significantly low body weight
- Intense fear of weight gain and/or acts to prevent weight gain
- Has body weight/shape disturbance and/or uses it to evaluate self-worth and/or doesn’t recognise seriousness (has to have one).
No longer has a BMI cut off, up to clinician. However, the lower the BMI the more likely complications are especially if they got there quickly.
Anorexia- severity (BMI)
- Mild >= 17
- Moderate 16-16.9
- Severe 15-15.9
- Extreme < 15
The visual presentation of anorexia nervosa
- Muscle wasting- loss of fat
- Skin pallor, dryness
- Lanugo hair on face/body- fine hair
- Poor circulation- blood pooling
- Thinning hair, brittle nails
- Abdominal bloating
- Oedema in extremities