Delayed puberty and hypogonadism in adolescents — branching viva

Opening framework

My framework has four layers. First, the timing — no testicular enlargement (under four millilitres) by 14 in boys or no thelarche by 13 in girls, or a stall of more than two years. Second, the gonadotrophin split — a morning testosterone or oestradiol with FSH and LH divides the differential into a central (hypogonadotropic) and a gonadal (hypergonadotropic) cause. Third, the clock-versus-furnace distinction — constitutional delay is a late but intact clock, permanent CHH is a defective clock, and primary gonadal failure is a clock with no furnace. Fourth, the induction principle — gradual sex-steroid escalation over 18 to 24 months to mimic normal puberty. ^[1]