Development Flashcards
What is thelarche?
Onset of female breast development
What is pubarche?
Appearance of sexual hair
What is adrenarche?
Onset of androgen-dependent body changes such as growth of axiliary and pubic hair
Whati s the definition of delayed pubertal development in girls?
Absence of breast development by age 13 Or No menarche by age of 16 or 3 years after breast development
What is the age of pubertal development in girls?
8-12
What hormonal changes lead to the onset of puberty?
Pulsatile secretion of GnRH begins Pulsatile secretion of LH and FSH from anterior pituitary HPO axis is activated Sexual maturation
What criteria forms the diagnosis of primary amenorrhea?
The absence of menses at age 16 in the presence of normal growth and secondary sexual characteristics If by age 13, menses has not occurred and the onset of puberty, such as breast development is absent, a work up for primary amenorrhoea should be considered
What are the top three causes of primary amenorrhoea?
Gonadal dysgenesis (46%) - 45 XO, 46XX (POI), 46XY GD Mullerian agenesis (15%) - MKRH Physiological delay of puberty (14%) - Constitutional, chronic systemic illness, acute illness
What is the incidence of ambiguous genitalia?
1:4000
What are three conditions that can cause ambiguous genitalia in an infant with a normal female karyotype?
Congenital adrenal hyperplasia Exposure in utero to increased maternal androgens Placental aromatase deficiency
What are five causes of ambiguous genitalia in an infant with a normal male karyotype?
Partial gonadal dysgenesis Complete androgen insensitivity syndrome Partial androgen insensitivity syndrome Defect in testosterone biosynthesis 5-alpha reductase deficiency
What is the Prader Staging System and the Stages
Staging system for degree of sexual ambiguity 1. Isolated clitoromegaly 2. Narrow vestibule with separate urethral and vaginal opening 3. Single urogenital sinus / labia majora partially fused 4. Microbe is 5. Isolated crypto-orchidism
Almost half of the newborns with ambiguous genitalia suffer with ___ and are at risk of ______________________
CAH Salt-losing crisis Hypoglycaemia and electrolyte disturbances should be assessed and treated urgently Lifelong steroid treatment will be required
What is the incidence of congenital adrenal hyperplasia?
1:10,000
What is the pathophysiology of Congenital adrenal hyperplasia?
Enzyme deficiency in the corticosteroid production pathway 21-hydroxylase (90%), followed in frequency by 11-beta-hydroxylase Production of cortisol is decreased ACTH is increased as a result of negative feedback This leads to hyperplasia of the adrenal gland Increased levels of 17-OHP are shunted towards the production of androgens
How is congenital adrenal hyperplasia diagnosed?
Raised serum levels 17-OHP (17-hydroxyprogesterone) In equivocal cases, the levels of cortisol and 17-OHP are measured 30 and 60 minutes after the administration of synthetic ACTH (Synacthen test)
What are the anatomical abnormalities seen in Congenital Adrenal Hyperplasia?
Varying degrees of virilisation Clitoral enlargement, scrotal appearance of the labia majora, single urogenital sinus Vagina can join the posterior wall of the urethra at varying levels
What is the incidence of partial and complete androgen insensitivity?
1:40-60,000 births CAIS > PAIS
How is Partial and complete androgen insensitivity syndrome inherited?
X-linked inheritance in 2/3 of cases
What is the pathophysiology of Partial and complete androgen insensitivity?
Normal testicular production of androgens Abnormal androgen receptors Virilisation of external genitalia is incomplete or absent because it is dependent on androgen receptor activity As the testes produce AMH, Mullerian structures regress The Fallopian tubes, uterus and upper 2/3 of the vagina are absent
What is the presentation of CAIS?
- Normal female appearance: normal breast development - Primary amenorrhoea (commonest presentation) - Scant or absent pubic / axillary hair - Blind vaginal pouch, UNambiguous labia and clitoris.
What is the presentation of PAIS?
Varying degrees of virilisation, ranging from defects in spermatogenesis and isolated hypospadias to ambiguous genitalia During puberty, some degree of virilisation occurs (as opposed to CAIS)
How is PAIS/ CAIS diagnosed? What investigations should you do in a work-up for CAIS and PAIS?
- Karyotype: 46XY - Testosterone level: normal adult male level - LH level: normal - Inhibin B level: mid-normal male range; related to uninhibited Sertoli cell function. - USS or MRI pelvis: to locate testes - hCG stimulation test (in the presence of ambiguous genitalia or normal female external genitalia): normal rise of testosterone
What is the management of CAIS / PAIS?
Disclosure of XY karyotype Psychological support Info: unable to menstruate or carry a pregnancy Hormone replacement therapy: oestrogen Vaginal dilatation to allow for intercourse Consideration of gonadectomy - ideally pre-pubertal in PAIS to avoid virilisation
What is the incidence of 5alpha reductase deficiency?
Unknown Geographical variation reported Increases with consanguinity
What is the pathophysiology of 5-alpha reductase deficiency
Deficiency in the enzyme that Converts testosterone to Di hydro testosterone DHT is a potent androgen that is required for fetal genital virilisation