Precocious and Delayed Puberty

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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).

Tanner Stages for Girls

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.

Delayed Puberty Diagnostic Algorithm 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).

Algorithm for Precocious and Delayed Puberty

⭐ 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).
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Practice Questions: Precocious and Delayed Puberty

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A child with decreased levels of LH, FSH and Testosterone presents with delayed puberty. Which of the following is the most likely Diagnosis

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No teeth till _____ months of age is called delayed eruption

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No teeth till _____ months of age is called delayed eruption

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Precocious and Delayed Puberty | Growth and Development - OnCourse NEET-PG