Precocious and Delayed Puberty

Normal Puberty & Definitions - Timing is Everything

• Normal Onset: Girls 8-13 yrs (thelarche); Boys 9-14 yrs (gonadarche).
• Definitions:
  • Precocious: Girls <8 yrs; Boys <9 yrs.
  • Delayed: Girls >13 yrs (no thelarche) or no menarche by 15 yrs; Boys >14 yrs (no gonadarche).
• Sequence (Girls): Thelarche → Pubarche → PHV → Menarche. (📌 B-P-P-M: Breast, Pubic hair, Peak height, Menarche)
• Sequence (Boys): Gonadarche → Pubarche → Spermarche → PHV.
• Hormonal Axis: Hypothalamic-Pituitary-Gonadal (HPG) axis activation. Adrenarche (adrenal androgens).

⭐ The first sign of puberty in girls is usually thelarche (breast budding), while in boys it is testicular enlargement (≥4ml volume or ≥2.5cm length).

Precocious Puberty - Early Bloomers Unveiled

• Onset of secondary sexual characteristics: Girls <8 yrs, Boys <9 yrs.
• Types:
  • Central (GnRH-dependent): Premature HPG axis activation.
    • Causes: Idiopathic (most common, esp. girls), CNS lesions (hamartoma, glioma).
  • Peripheral (GnRH-independent): Excess sex steroids (gonadal/adrenal/exogenous).
    • Causes: McCune-Albright syndrome (MAS), CAH, tumors (ovarian, testicular, adrenal).
• Clinical: Early thelarche/menarche (girls); testicular enlargement (>4ml or >2.5cm) (boys); accelerated growth, advanced bone age.
• Investigations:
  • Bone Age (X-ray hand/wrist).
  • Basal LH, FSH; Estradiol/Testosterone.
  • GnRH Stimulation Test: Differentiates Central (↑LH) vs. Peripheral (↓LH).
  • Imaging: Brain MRI (if Central); Pelvic/Testicular USG.
• Management:
  • Central: GnRH agonists (e.g., Leuprolide).
  • Peripheral: Treat underlying cause.

  ⭐ McCune-Albright Syndrome: Triad of polyostotic fibrous dysplasia, irregular café-au-lait spots ("Coast of Maine" border), and autonomous endocrine hyperfunction (e.g., GnRH-independent precocious puberty).

Delayed Puberty - Late Starters Explained

• No secondary sex characteristics: girls by 13 yrs, boys by 14 yrs. No menarche by 16 yrs.
• Causes:
  • Constitutional Delay of Growth & Puberty (CDGP): Most common, family Hx. "Late bloomers".
  • Hypogonadotropic Hypogonadism (↓FSH/LH): Kallmann (anosmia), CNS issues (tumors), chronic illness, malnutrition.
  • Hypergonadotropic Hypogonadism (↑FSH/LH): Gonadal failure (Turner XO, Klinefelter XXY), chemo/radiotherapy.
• Clinical Features:
  • Girls: No thelarche by 13 yrs, no menarche by 16 yrs.
  • Boys: Testicular volume < 4ml or length < 2.5cm by 14 yrs.
  • Short stature, delayed bone age.
• Investigations:
  • Bone age (X-ray wrist).
  • Hormones: LH, FSH, Estradiol/Testosterone. Karyotype.
  • GnRH stimulation test (differentiates CDGP from hypogonadotropic hypogonadism).
  • Imaging: Pelvic USG (girls), MRI brain (if CNS signs/symptoms).
• Management:
  • CDGP: Reassurance. Short-term low-dose sex steroids if significant psychosocial distress.
  • Specific: Treat underlying cause. Hormone Replacement Therapy (HRT).

⭐ Constitutional delay of growth and puberty (CDGP) is the most common cause of delayed puberty, often with a positive family history.

Mnemonic: 📌 "LATE": Low hormones (central), Age (bone age delayed), Turner's/Klinefelter's (gonadal), Expectant (constitutional).

Diagnostic Algorithm - Pubertal Puzzles Solved

• Precocious Puberty (PP): Girls <8 yrs, Boys <9 yrs. Central (↑LH, GnRH-dependent) vs Peripheral (↓LH, GnRH-independent).
• Delayed Puberty (DP): Girls >13 yrs (no thelarche), Boys >14 yrs (testes <4ml). Hypo-gonadotropic (↓LH/FSH, e.g. CDGP) vs Hyper-gonadotropic (↑LH/FSH, e.g. Turner's).

⭐ CDGP: bone age delayed, matches height age.

High‑Yield Points - ⚡ Biggest Takeaways

• Precocious Puberty: Girls < 8 yrs, Boys < 9 yrs. Central (GnRH-dependent) is most common; treat with GnRH agonists.
• Peripheral Precocious Puberty: GnRH-independent. Key causes: CAH, gonadal tumors, McCune-Albright syndrome.
• Delayed Puberty: Girls > 13 yrs (no breast development), Boys > 14 yrs (no testicular enlargement).
• Constitutional Delay (CDGP): Most frequent cause of delayed puberty; characterized by delayed bone age.
• Kallmann Syndrome: Hypogonadotropic hypogonadism with anosmia. Differentiate from hypergonadotropic causes (e.g., Turner's, Klinefelter's).