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Puberty - Normal and Abnormal
- 1. PUBERTY – NORMALAND ABNORMAL
- 2. OUTLINE • Definitions • Normalpuberty • At birth • Pubertal events • Abnormal puberty • Precocious puberty • Delayed puberty
- 3. DEFINITIONS • ADOLESCENCE -the period of life during which a child becomes an adult i.e. the physical , sexual and psychological development are complete. • PUBERTY - a physiological phase lasting 2 to 5 years, during which the genital organs mature. It represents the first stage of adolescence • THELARCHE – breast growth • ADRENARCHE/PUBARCHE – increased activity of the suprarenal cortex at puberty with increased production ofadrenal androgens resulting in pubic hair (and axillary hair) growth • MENARCHE– onset of menstruation
- 4. OESTROGEN FEEDBACK SYSTEM Hypothalamus •Gonadotropin releasing hormone (GnRH) • Initially highly sensitive to negative feedback exerted from oestradiol • At puberty – sensitivity decreases Anterior Pituitary • Follicle stimulating hormone (FSH) • Luteinising hormone (LH) Ovaries • Follicular development • Oestrogen secretion
- 5. FACTORS ASSOCIATED WITHONSET OF PUBERTY • Genetics • Height and weight ratio (nutritional factors) • Critical weight for menarche – 47.8kg • Increased fat deposition from 17% to 23% for ovulation • Therefore increased BMI = earlier menarche • Maturation of the hypothalamus – sensitivity to oestrogen feedback system • Increased neurotransmitter output in CNS • Onset of adrenal androgen activity
- 6. EFFECTS OF OESTROGEN •Secondary sexual characteristics • Thelarche • Pubic/axillary hair growth to a small extent • Skeletal growth growth spurt • Menarche: • Midpuberty oestrogen endometrial proliferation significant enough to result in the first menstruation • Genital organ changes: • Vaginal length increases along with the size of the mons pubis, labia majora and minora • Vaginal rugae become apparent, epithelium becomes thickened stratified squamous containing glycogen • Acidic environment • Uterus and ovaries enlarge. Uterus:cervix ratio 2:1 • 2 million follicles present at birth are now closer to 300 000
- 7. SUMMARY OF PUBERTALEVENTS Thelarche • 9.8 – 10.5 years • Skeletal growth occurs simultaneously Adrenarche • 10.5 – 11 years Menarche • 12.8 years • Mean interval between thelarche and menarche is approximately 2.5 years
- 8. ABNORMAL PUBERTY • Precociouspuberty: Appearance of secondary sexual characteristics before age 8 OR menarche before age 9 • Delayed puberty: Sexual characteristics don’t develop by the age of 14 OR no menstruation until age 16
- 9. ABNORMAL PUBERTY Precocious puberty: •True precocious puberty: due to increased pituitary gonadotropins (LH and FSH) • Pseudo-precocious puberty: due to increased sex steroids – peripheral origin • Incomplete precocious puberty: only one pubertal change - such as thelarche or adrenarche before the age of 8 years - without the presence of any other pubertal changes and in absence of increased oestrogen production. The other pubertal changes occur at the normal age.
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- 11. • Constitutional –premature maturation of the hypothalamic-pituitary- ovarian axis GnRH is secreted earlier which stimulates sex steroid production puberty occurs in the normal order but earlier
- 12. Intracranial lesions • Ventricularhamartoma • Pineal tumour • Craniopharyngioma • Astrocytoma • Glioma • Neurofibroma • Ependymoma • Suprasellar teratoma • Hydrocephalus • Cerebral palsy • Infections Within the hypothalamus Near the hypothalamus CNS causes
- 13. Extracranial lesions –tumours that secrete gonadotropins • Ectopic gonadotropin-secreting tumours of the ovary • Dysgerminoma – malignant germ cell tumour occurring in the ovary • Choriocarcinoma – secretes HCG which stimulate ovarian secretion of oestrogen • Hepatoblastoma Hypothyroidism – severe hypothyroidism causes increased levels of TSH and FSH • Cross reactivity of TSH on FSH receptor OR • Direct ovarian stimulation from FSH • Short stature, delayed bone age, thelarche, genital development, pubarche, menstruation
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- 15. GnRH independent causes– unprovoked by hypothalamus Feminising tumours • Ovarian - granulosa cell tumour • Adrenal - adrenoblastoma • Often palpable in the abdomen Exogenous oestrogen • Injection of oestrogen preparations • Oestrogen contamination of food
- 16. McCune-Albright syndrome • Dueto a sporadic somatic mutation (occurring after conception) • Diagnosis is based on a triad of signs of which 2 must be present: • Precocious puberty – usually early menarche • Café-au-lait spots – large, irregularly shaped, usually on upper body and face; present from birth • Polyostotic fibrous dysplasia – develop fibrous tissue in bones resulting in pathological fractures • Other associated features: • Ovarian cysts • GH/prolactin-secreting adenomas • Hyperthyroidism • Adrenal hypercortisolism – cushing’s syndrome • Osteomalacia • Treatment: inhibit ovarian steroidogenesis - testolactone
- 17. INCOMPLETE PRECOCIOUS PUBERTY Premature thelarche Unilateral/bilateral Waxesand wanes Normal puberty and reproduction follows Premature menarche Rare Consider infections, foreign body, abuse or trauma, local neoplasms Premature adrenarche Due to early rise in adrenal androgens May be associated with anovulation, hirsutism and hyperinsulinaemia.
- 18. APPROACH TO PRECOCIOUSPUBERTY History •Exclude iatrogenic source of oestrogen/androgen •Exclude life-threatening causes eg tumour of CNS, ovary, adrenal •Trauma, foreign body, abuse Examination •Weight/height = BMI; Tanner stage •Genitalia exam •Abdomen/pelvis – tumours, local causes •Neurological/Opthalmologic – CNS tumours/infections •Features of McCune-Albright syndrome or hypothyroidism Investigations •Biochemistry – FSH/LH/Prolactin/Oestrogen/Testosterone/TSH/HCG/provocative tests - GnRH •X-ray – wrist for bone age •U/S abdomen/pelvis – exclude tumours of ovaries, adrenals, liver •CT brain - tumours
- 19. TREATMENT GOALS Treat underlying cause Intracranial disease/extracranial disease Neurosurgical intervention/local surgicalexcision Arrest maturation/gain control over established characteristics Medroxyprogesterone Slows down breast and genital development Maximise eventual height GnRH agonist Delays epiphyseal fusion
- 20. PSYCHOSOCIAL ASPECTS • Counsellingparents and child in order to avoid abuse • Reduce emotional problems • Provide contraception if necessary
- 21. no signs ofsecondary sexual development by the age of 14 OR no menstruation by age 16 Delayed puberty • Delayed onset: Breast bud does not appear till 13 years or menarche does not occur till 16 years • Delayed progression: Menarche does not occur within 5 years after breast bud
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- 23. HYPERGONADOTROPIC HYPOGONADISM Low oestrogenlevel is due to ovarian failure rather than loss of gonadotropin stimulation CONGENITAL ACQUIRED Turner’s syndrome Surgical/traumatic castration Swyer syndrome Autoimmune ovarian failure Mixed gonadal dysgenesis Chemotherapy/radiotherapy Pure gonadal dysgenesis Infections Gonadal dysgenesis
- 24. HYPOGONADOTROPIC HYPOGONADISM Low oestrogenresulting from low gonadotropins. Causes may be generalised or focal, reversible or irreversible REVERSIBLE CAUSES IRREVERSIBLE CAUSES Physiologic delay GnRH deficiency Hypopituitarism Nutritional disorders Excessive weight loss/energy expenditure Malnutrition Anorexia nervosa Congenital CNS defects Kallmann’s syndrome – delayed puberty and anosmia Acquired – post surgery/radiotherapy damage Prolactinoma CNS tumours – craniopharyngioma Endocrinopathies Hypercortisolism (Cushings) Hypothyroidism Prader-willi syndrome – short stature, obsessive eating, hypotonia CHARGE syndrome
- 25. EUGONADISM Normal levels ofgonadotropins and sex steroids – defect is at end- organ • Mullerian duct agenesis – congenital absence of uterus and vagina • Uterovaginal plate – complete vaginal septum with imperforate hymen • Intersex disorders – androgen insensitivity
- 26. APPROACH TO DELAYEDPUBERTY History •Exclude obvious genetic disorders •Sense of smell? Diet/exercise habits? Cognitive defecits? •Exclude previous trauma/medical therapy resulting in damage •Exclude life-threatening causes eg tumour of CNS, ovary, adrenal Examination •Weight/height = BMI; Tanner stage •Genitalia exam – ambigious genitalia •Abdomen/pelvis – tumours, local causes •Neurological/Opthalmologic – CNS tumours/infections Investigations •Biochemistry – FSH/LH/Prolactin/Oestrogen/Testosterone/TSH/HCG/provocative tests - GnRH •X-ray – wrist for bone age •U/S abdomen/pelvis – exclude tumours of ovaries/assess anatomy •CT brain – tumours •Genetic - karyotype
- 27. TREATMENT PRINCIPLES Treat underlying cause Tumours/infections XYpatients – gonadectomy and sex hormone treatment Develop secondary sexual characteristics/growth spurt Appropriately timed hormone treatment Gradually increasing increments of oestrogen therapy Counselling/reassurance/ monitoring Especially if constitutional delay is suspected
Editor's Notes
- #5 At birth oestradiol suppresses hypothalamus from secreting GnRH At puberty, there is decreased sensitivity to negative oestrogen feedback GnRH secretion to upregulate oestrogen and progesterone secretion