Puberty and Its Pathophysiology Pediatrics Course 4th Year

Puberty is a complex developmental process culminating in sexual maturity. This transitional period begins in late childhood and is characterized by maturation of the hypothalamic-pituitary-gonadal axis, the appearance of secondary sexual characteristics, acceleration of growth, and, ultimately, the capacity for fertility. Puberty - Definition

Puberty – Characteristic and Environmental Factors Centrally driven H-P-G axis GH and Gonadotropins secretion General health, nutrition, exercise Genetic influences, race Socio-economic conditions Programmed from intra-uterine environment Puberty – Characteristic and Environmental Factors

Hypothalamic-Pituitary-Gonadal Axis - Fetal Hypothalamic-Pituitary-Gonadal Axis - Early Infancy Hypothalamic-Pituitary-Gonadal Axis – Childhood Hypothalamic-Pituitary-Gonadal Axis - Late Prepuberty Hypothalamic-Pituitary-Gonadal Axis - Puberty

Puberty Contemporary Issues in Pathophysiology

Onset of Puberty

Sequence Of Normal Puberty

Pubertal development as precocious when it occurs before the ages of 8 years in girls and 9 years 6 months in boys In at least 50% of cases of precocious pubertal development, pubertal manifestations will regress or stop progressing, and no treatment is necessary Gonadotrophin-dependent (true / central) Gonadotrophin-independent Precoucious Puberty

Delayed onset of puberty is defined as occurring older than 2 SD after the average age Girls >13.4 years old Boys >14 years old Constitutional delay Commonest condition seen by paediatric endocrinologists Positive family history Height prognosis appropriate for parental centiles, although in severe cases upper body may remain short Bone age is delayed & consistent with degree of pubertal maturation (usually delayed by 2 years or more) Often associated with constitutional short stature Progressive height gain, but along lower limits of normal (contrast to isolated gonadotropin deficiency which has normal growth, but no pubertal growth spurt) Treatment for psychological reasons, with low dose ethinyloestradiol: onset of breast development with a growth spurt and problem usually resolves Delayed Puberty

Delayed onset of puberty is defined as occurring older than 2 SD after the average age Girls >13.4 years old Boys >14 years old 1. General Constitutional delay of growth and puberty Malabsorption Underweight Chronic illness 2. Gonadal failure (Hypergonadotrophic hypogonadism) Turner’s Syndrome Post-malignancy chemo / radiotherapy / surgery Polyglandular autoimmune syndromes 3. Gonadal deficiency Congenital hypogonadotrophic hypogonadism Hypothalamic/pituitary lesions Rare gene mutations inactivating FSH/LH or their receptors Delayed Puberty

Assessment of Puberty History Review of Systems Examination of Growth Pubertal Assessment (Tanner staging) Neurological assessment Assessment of Puberty

Assessment of Puberty Review of Systems Examination of Growth - Role of bone age Female skeletal maturity is generally 2 years advanced as compared to males Pubertal events more correlated with bone age than chronological age Pubertal Assessment (Tanner staging) Axillary hair Pubic hair & staging Breast development & staging Genital development & staging Neurological assessment Assessment of Puberty