Disorders of Puberty Flashcards
What are some timings of Puberty?
Normal Timing of Puberty: Age of Onset
- Boys: 12y (9.5-13.5Y)
- Girls: 11y (8.5-13y)
Delayed
- Boys >14
- Girls: >13
Precocious Puberty
- Boys: <9y
- Girls: <8y
What are some sequences of puberty in girls?
- Breast buds
- Fastest rate of growth in height
- Menarche
- Adrenarche
What are some sequences of puberty in boys?
- Testes 4ml in volume
- Fastest rate of growth in Height
- Testes 10-12ml in volume
- Voice change
- Testes Enlargement to 25ml
- Facial hair
What is some basic physiology in Puberty?
- Hypothalamus – GnRH neurones
- Release GnRH which binds to pituitary
- Pituitary (anterior)
- Release LH and FSH in response to GnRH to interact with Ovary or Testes
- Ovary releases oestrogen and Testes release testosterone (coverted to dihydrotestosterone) in response.
What are factors involved in puberty’s biological clock?
- Environment
- Neuroendocrine
- Genetics
- Nutrition, Energy
How is the GNRH pulse generator regulated?
- KISS neurone
- KISS Petins
- Leptin
\what are the differenct classifications of early or Precocious Puberty?
- Isolate premature thelarche and Thelarche Variant
- Central / Gonadotrophin dependent precocious puberty (CPP)
- Gonadotrophin independent precocious puberty (GIPP)
- Isolated premature adrenarche
What are features of Isolate premature thelarche and Thelarche Variant?
Breast Development
- Proper Breast development is always the effect of oestrogens. Premature thelarche doesn’t necesasarly always relate to the effects of oestrogens
What are features of Central/Gonadotrophin dependent precocious puberty (CPP)?
Testes enlargement
What are features of Gonadotrophin independent precocious puberty (GIPP)?
- PV bleeding
- Pubic Hair
- Breast Development
- Testes Enlargement
What are features of Isolated Premature Adrenarche?
Pubic Hair
What are causes of Gonadotrophin Independent Precocious Puberty?
- McCune Albright Syndrome: Somatic Activating mutation in the α-subunit of the G-Protein (Gsα)
- Familial Testotoxicosis or male limited GIPP: Activating mutation of LH receptor (G-Protein Coupled Receptor). It is Autosomal Dominant
- Congenital Adrenal Hyperplasia
What are the differences between Premature Thelarche and Thelarche Variant?
Premature Thelarche
- 6m – 2y
- Uni- or bilateral
- No nipple development
- Height Velocity normal
- Bone age not advanced
- No Ix necessary follow-up important
Therlarche Variant
- 2 - 6y
- Cyclic breast development HVé
- BA advanced
- FSH dominance
What are causes of central precocious puberty?
- Congenital: Septo-Optic Dysplasia
- Hypothalamic-pituitary tumours: Hamartoma, Optic Nerve Glioma, Pineal cyst, Hydrocephalus
- Post-injury: Trauma, Radiotherapy
- Post-infection: Meningitis, Encephalitis
- Neurofibromatosis
- HCG producing tumours: Germinoma
What are symptoms of McCune Albright syndrome?
- Café-au-lait pigmentation
- Progressive Bone disorder – polyostotic fibrous dysplasia
- GIPP
What is Normal and Precocious Adrenarche?
Normal
- ~ 2 years before gonadal maturation
- Separate and independent from gonadal maturation
- No effect on timing of true puberty
Premature
- Before 8 years in girls, 9 years in boys
- Occurs with increased frequency between 3 and 8 years age(F:M 10:1)
- Increased frequency in children with Cerebral dysfunction (F:M 1:1), Obesity, Afro-Carribean
What are causes of Functional Hypogonadotrophic Hypogonadism?
Endocrine cause
- GH deficiency
- Hypothyroidism
- Hyperprolactinemia
- Noonan syndrome
Chronic disease
- Asthma
- Crohn’s disease
- Celiac disease
- Poor nutrition/poor weight gain
- Juvenile arthritis
What are causes of Gonadotrophin Deficiency?
- H-P development: DAX1, SOD
- GnRH processing: PC1
- GnRH signalling: GnRH receptor
- Syndromes: Prader-Willi
- Acquired H-P lesions: Craniopharyngioma
What are causes of Hypergonadotrophic Hypogonadism in boys?
- Klinefelter Syndrome (47, XXY): Tall stature, Gynaecomastia (imbalance between oestrogen and androgen)
- Mixed gonadal dysgenesis 46XY/45X
- Testicular Dysgenesis
- LH resistance
- SF1, StAR, Cyp11a, HSD3B2, HSD17B2, PAIS [46XY]
- Trauma, Radiotherapy, Chemotherapy
- Anorchia
- Cryptochidism
What are causes of Hypergonadotrophic Hypogonadism in boys?
- Turner Syndrome (45, X): Short Stature, No breast development
- Fragile X associated
- Mixed gonadal dysgenesis 46XY/45X
- Ovarian dysgenesis
- LH resistance
- FSH resistance
- SF1, StAR, Cyp11a, HSD3B2, Cyp17, aromatase (Cyp19) [46XX
- HSD17B2, AIS, SRD5A2 [46XY sex reversal]
- Trauma, Radiotherapy, Chemotherapy
- Autoimmune
- Metabolisc (galactosaemia)
How do Gonadotrophins influence testes?
- You need gonadotrophins to increase the size of testes.
- Testosterone replacement is not enough
