Endo & Growth Flashcards
what is the MOST common cause of precocious puberty in girls?
Idiopathic
presents just like normal puberty
what is the staging for puberty?
Tanner staging
What are the outcomes of premature therlache?
Persists
Regresses
Does NOT progress to precocious puberty (eg secondary sexual characteristics)
what is the best immediate diagnostic measure to test for CAH?
17aOH progesterone levels (though this condition itself is a defficiency of 21 alpha hydroxylase)
random level AND 72hour levels
Why is CAH called CAH?
deficiency of end hormones leads to overstimulation of adrenal gland by ACTH = hyperplasia of the adrenal glands! (+ excess androgens)
what is CAH?
Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders characterized by impaired cortisol synthesis.
It results from the deficiency of one of the five enzymes required for the synthesis of cortisol in the adrenal cortex.
Most of these disorders involve excessive or deficient production of such hormones as glucocorticoids, mineralocorticoids, or sex steroids, and can alter development of primary or secondary sex characteristics in some affected infants, children or adults.
It is one of the most common autosomal recessive disorders in humans
what is the most common cause of a disorder of sexual development?
CAH
which are the most deficient hormones in CAH?
More than 90% show a deficiency of 21-hydroxylase – needed for cortisol
- 80% are unable to produce aldosterone – leading to decreased Na and increased K (hyperkalaemia)
- Cortisol deficiency stimulates pituitary to increase ACTH → overproduction of adrenal ANDROGENS
How does CAH present?
Classic forms:
- Simple-virilising 25%: Virilization (masculinisation) of external genitalia in female infants → clitoromegaly and variable fusion of labia ( +ambiguous gentialia)
• In males → enlarged penis, pigmented scrotum
-> if not identified and treated they will grow rapidly and have more virilisation:
present tall, muscular, pubic hair, acne, precocious puberty
• Boys - enlarged penis, small testes
• Girls - abnormal or absent periods, facial hair
2• Salt-wasting: in 75% of cases of severe enzyme deficiency, insufficient aldosterone production can lead to salt wasting, failure to thrive, and potentially fatal hypovolemia and shock.
The missed diagnosis of salt-loss CAH is related to the increased risk of early neonatal morbidity and death.
Non-classic:
1. The non-classic form is characterized by mild subclinical impairment of cortisol synthesis; serum cortisol concentration is usually normal.
presentation : late in childhood, accelerated growth, premature sexual maturation
what causes the hypoglycaemia in CAH?
cortisol deficiency
what ivx do we conduct for CAH and what are the findings?
In classic 21-hydroxylase deficiency, laboratory studies will show:
Increased 17α-hydroxyprogesterone in blood (precursor for deoxycortisol so cortisol)
- random and 72 hour levels
• ↑ testosterone, progesterone, adrenal androgen precursors
U&Es -> • In salt losers → low Na, high K, metabolic acidosis, (as aldosterone is low),
Blood glucose - > hypoglycaemia
If virilisation:
Karyotype with fluorescent in situ hybridization (FISH) for sex-determining region of the Y chromosome
how does a Salt losing adrenal crisis present?
→ aged 1-3w MALE
-> salt losers
→ vomiting, weight loss, floppiness, circulatory collapse ± arrhythmias, dehydration and hypoglycemia
what is the mx AND follow up of CAH?
Mx:
• MDT involving endocrinologists, urologists and paeds
• Female
o Corrective surgery to external genitalia if required
- there is a debate surrounding gender assignment
- Lifelong glucocorticoids (hydrocortisone) to suppress ACTH and testosterone
- Mineralocorticoids (fludrocortisone) if there is salt loss
Regular blood tests → monitoring of growth, skeletal maturity, plasma androgens, 17α-hydroxyprogesterone to allow adjustment of steroid replacement doses
- Additional hydrocortisone to cover periods of illness or surgery
- Child may have short stature so may benefit from GH replacement
- Males usually have normal fertility but females may have problems conceiving so may need additional help
what is the mx of a salt losing crisis?
• Male
o Salt losing adrenal crisis → saline, dextrose, IV hydrocortisone
what is the 2nd most common enzyme deficiency in CAH?
what would ivx show?
11β-Hydroxylase CAH (5%)
ivx would show increased 11-Deoxycortisol as it catalyses the conversion of 11-Deoxycortisol→DOC
define delayed puberty?
the lack of any pubertal signs by 14 years in boys (m = no testicular development)
and 13 years (f = no breast development) or 15 (no periods).
what are the CAUSES OF DELAYED PUBERTY?
- Constitutional delay – commonest
short stauture because of a delay in the onset
of puberty - LOW Gonadotrophin secretion = Hypogonadotrophic hypogonadism
a. Systemic disease – CF, severe asthma, Crohn’s, organ failure, anorexia nervosa, starvation, XS exercise
b. Hypothalamo-pituitary disorders – panhypopituitarism, intercranial tumours, Kallmann syndrome (LHRH deficiency and anosmia), isolated gonadotrophin or GH deficiency
c. Acquired hypothyroidism
- Failure of end organ with HIGH Gonadotrophin secretion = Hypergonadotrophic hypogonadism
a. Chromosomal abnormalities – Klinefelter’s 47XXY, Turner’s 45 XO
b. Steroid hormone enzyme deficiencies
c. Acquired gonadal damage – post-surgery, chemo, radio, trauma, torsion of testes, AI disease
what is the aetiology of Constitutional delay?
Majority simple constitutional delay - late bloomers - not requiring detailed investigation
- More common in males
- Often familial – usually FHx of same in parent of same sex
• Also associated with dieting and XS exercise
• Children are short during childhood, delay in sexual maturation and delayed skeletal maturity
delayed bone age
• Legs are long in comparison to back
how do we ivx constitutional delay or delayed puberty?
- Height and weight of child - plot on growth curve
- Compare to mid-parental heights
- Assess for features of malnutrition
- Assess for features of disproportion eg webbed neck, longer legs (kleinfelter)
- Cranial nerve and neuro exams - identify brain tumours, anosmia - kallmans
Boys → pubertal staging - Tanners (testicular volume), Karyotype (Kleinfelters)
• Girls → Karyotype (Turner’s), thyroid and sex steroid hormone levels
Also:
- Non dominant wrist xray: delayed bone age
- Blood - basal FSH,LH (low in HypoHypo, High in gonad disease)
- LHRH stimulation test
• Use LHRH to stimulate gonadotrophins then measure LH and FSH
TFTs → if hypo
• Also ask for prolactin
Consider MRI brain for structural causes eg tumours
- Look for signs of chronic disease, dysmorphia, plot height and weight, calculate mid-parental height
- Can only diagnose once other causes have been eliminated
how do we mx constitutional delay?
- Reassurance as treatment not usually required
- They will eventually reach their target height
Boys:
• Oral oxandrolone can be used (3-6 months) for catch up growth - but not secondary sexual characteristics.
- ONLY give if psychosocial distress present
- Can give testosterone - get 2ndary characteristics
- Females can be treated with oestradiol for same reason
- Consider need for psych input regarding bullying, body image, social etc
Pubertal development and progress are best assessed by ______ ?
Tanner staging
what are the signs of puberty in BOYS in order?
- The first sign of puberty in boys is an increase in the size of the testes. enlargement to over 4-mL volume
measured - This is followed by penile and scrotal changes.
- Growth of axillary + pubic hair and other changes, such as changes of the voice
Rapid height growth is next, occur in mid- to late puberty - (12 mL to 15 mL testicular volume) - 18 months post first sign of puberty
- Facial hair does not appear until late puberty.
Testicular size is documented as a measurement of the longest axis or by the testicular volume using the Prader orchidometer.
what are the signs of puberty in GIRLS in order?
The first demonstrable sign of puberty in girls is breast development (palpable breast disc).
Pubic and axillary hair, acne, and body odour develop as a result of androgens secreted from the adrenal gland. occur almost immediately after breast development
The peak growth spurt occurs in Tanner stage 3 breast development,
and menarche occurs in Tanner stage 4 breast development . Menarche occurs 2.5 years after the
start of puberty and signals that growth is coming
to an end, with only around 5-cm height gain
remaining
Caution must be exercised in examination of breast tissue in obese girls, as simple fat may be mistaken for breast tissue.
define puberty
Puberty = interval characterized by the acquisition of secondary sexual characteristics, accelerated linear growth, increase in secretion of sex hormones, maturation of gonads (testes in boys and ovaries in girls), potential for reproduction.