PubertyNormally there is a negative feedback on the hypothalamus in childhood. With the onset of puberty, this negative feedback is removed and there is a significant increase in the amplitude of pulsatile release ere ease of GnRH from the hypothalamus leading to puberty.
Age of puberty in girls - 8 to 13.5 years.
Sequence of puberty in girls.
B = Breast buddingffhelarche
P = Development of pubic hair pubarche and Axillary hair - Adrenarche
H = Increase in height/growth spurt in
Males = Menarche
Mnemonic-BPH in Males.
Development of breast and pubic hair occurs in 5 stages as described by tanner called as Tanner staging for breast and pubic hair development.
Note: There is no need to know complete Tanner staging, so just remember. Tanner stage 1 and 2 ~ refers to initial stage of breast development/less developed, breast or pubic hair.
Tanner stage 4 and 5 - refers to advanced .stages of breast and pubic hair development or fully developed breast and pubic hair.
Delayed PubertyDelayed puberty is said to occur when there is no breast development by the a e of 14 and no menarche by age of 16
Causes of Delayed Puberty
- Constitutional delay (M/ c cause of delayed puberty in boys and overall M/c cause of delayed puberty).
- Hypogonadotropic hypogonadism: Defect is at the level of hypothalamus or pituitary. FSH level low < 10 m IU / ml.
DOC for treating hypogonadotropic hypogonadism = Oestrogen/ (ethinyl estradiol) in order to promote breast development and somatic growth.
- Hypergonadotropic Hypogonadism
- Defect lies at the level of ovary.
- There is sexual infantilism and FSH levels are elevated (as the negative feedback on FSH by oestrogen decreases) Levels of FSH > 30 m lU / ml.
- Turners syndrome (40 X O)
- Pure gonadal dysgenesis 46 XX, 46 XY
- Ovarian failure
- Infections like mumps or tuberculosis of ovary
- Iatrogenic (post-surgery /radiotherapy)
- Sweyers syndrome
- Primary ovarian failure
M/c cause of primary amenorrhoea and delayed puberty in females- Turner Syndrome Turner Syndrome
Syndromes associated with delayed puberty-
Prader will syndrome - An autosomal deletion and imprinting disorder associated with obesity. Emotional instability and delayed puberty due to hypothalamic dysfunction.
Laurence Moon Biedl syndrome: Hypothalamic amenorrhea + mental retardation + polydactyly + retinitis pigmentosa.
Frohlich syndrome - hypo gonadotropic hypogonadism (delayed puberty) + obesity + genital hypoplasia.
Swyers syndrome (46 XV) - Also leads to delayed puberty. It is caused by mutation or structural abnormality of Y chromosome. Patients have normal to tall stature.
Precocious pubertyDefinition: Development of secondary sexual characters before the age of 8 years.
Precocious menstruation is defined as onset of menses before 10 years of age.
Precocious puberty (PP) is of two varieties:
- True/central/GnRH dependent (80%) and
- Pseudo/peripheral/GnRH independent (20%)
MC cause = idiopathic/constitutional
- McCune-Albright syndrome consists of PP, polyostotic fibrous dysplasia, and cafe au lait spots. It is an example of peripheral PP, as ovaries are the source of estrogen in this condition. It may also be associated with hyperthyroidism/hyperparathyroidism/ hypercortisolism/ acromegaly
- DOC for PP is GnRH analogs.
- GnRH analogs:
Agonists cause initial "flare up" reaction followed by desensitization and downregulation of receptors
- The end point of both agonist and antagonist is the same, that is, to stop ovarian hormone production (medical castration)
- Medical management of endometriosis
- To decrease the size of fibroids
- Precocious Puberty (PP)
- Before in vitro fertilization (IVF) to downregulate the ovaries (so there is better response to subsequent stimulation of gonadotropins)
- Before endometrial ablation/resection for Dysfunctional Uterine Bleeding (DUB) (to thin out the endometrium)
- CraniopharyngioJIla is the MC neoplasm associated with delayed puberty
- NOTE: Kallmann Syndrome (Deficient GnRH Secretion): Hypogonadotropic Hypogonadism Associated with Anosmia Inheritance: X linked/ AR/ AD
- KAL gene mutation, failure of production of gene product (Anosmin-1)
- May be associated with hearing loss, ataxia color blindness, and cleft lip/palate
Perrault SyndromeGonadal dysgenesis (46 XX) and sensory neural deafness.
Ambigious genitalia is due to exposure to an
increased androgen levels in intrauterine life.
Ambiguous genitalia is due to androgen
insensitivity or decreased androgen levels.
Ambiguous genitalia is due to exposure to an increased androgen levels in intrauterine life.
Eg.. M/c cause: Testicular
5-alpha reductase deficiency
Congenital lipoid adrenal
M/c cause: Congenital adrenal hyperplasia
Maternal ovarian androgen secreting tumours
Maternal drug intake (Testosterone, Danazol)