Disorders of Puberty

Normal Puberty & Definitions - Setting the Stage

• Onset: Girls 8-13 yrs, Boys 9-14 yrs.
• HPG Axis: GnRH → LH/FSH → Estrogen/Testosterone. Adrenarche (DHEA-S) distinct.
• Sequence (Girls): Thelarche → Pubarche → PHV → Menarche. (📌 T-P-P-M)

  ⭐ Girls: Thelarche → Pubarche → PHV → Menarche is the typical sequence.

• Sequence (Boys): Testes ≥4ml → Pubarche → Penile growth → PHV.
• Tanner Stages: (B, PH, G 1-5). Key stages: B2-Bud; PH2-Hair; G2-Testes 4ml.

Precocious Puberty - Too Soon, Too Fast

Onset of secondary sexual characteristics < 8 yrs (girls), < 9 yrs (boys).

• Classification & Causes:

  • Central (GnRH-dependent): Early HPG axis activation.
    • Causes: Idiopathic (commonest), CNS tumors (hamartoma, glioma), hydrocephalus, CNS infection/trauma.
  • Peripheral (GnRH-independent): Excess sex steroids from gonads/adrenals or exogenous.
    • Causes: McCune-Albright syndrome, CAH, gonadal tumors (ovarian, testicular), adrenal tumors, exogenous steroids.

• Key Investigations:

  • Bone Age (Advanced).
  • LH, FSH (Basal & GnRH stimulated: ↑LH in Central).
  • Sex steroids (Estradiol, Testosterone).
  • Imaging: Pelvic USG, Brain MRI (if Central suspected).

• Management:

  • Central: GnRH analogs (e.g., Leuprolide).
  • Peripheral: Treat underlying cause.

⭐ McCune-Albright Syndrome triad: polyostotic fibrous dysplasia, café-au-lait spots (irregular "coast of Maine" borders), and autonomous endocrine hyperfunction (e.g., precocious puberty).

Delayed Puberty - Waiting Game Woes

• Definition: Absence of pubertal signs by age 13 yrs in girls or 14 yrs in boys.
  • Girls: Also no menarche by 15-16 yrs, or >5 yrs after thelarche (breast development).
• Classification & Flow:

• Key Causes:
  • Constitutional Delay of Growth & Puberty (CDGP): Most common, often familial.
  • Gonadal Failure: Turner's Syndrome (girls), Klinefelter's Syndrome (boys).
  • Hypothalamic/Pituitary Dysfunction: Kallmann syndrome, CNS tumors, chronic illness, malnutrition.
• Investigations:
  • Bone Age (X-ray left hand/wrist): Typically delayed in CDGP.
  • Hormonal Assays: LH, FSH, Estradiol/Testosterone.
  • Karyotyping: Indicated if suspecting Turner's or Klinefelter's (especially with ↑FSH/LH).
  • Prolactin, Thyroid function tests (TSH, FT4).
  • Cranial MRI: If neurological signs present or suspected CNS pathology (e.g., with ↓LH/FSH).
• Management:
  • Treat the specific underlying cause identified.
  • Hormone Replacement Therapy (HRT): Low-dose sex steroids (estrogen for girls, testosterone for boys) to induce puberty if necessary.
  • Reassurance and watchful waiting for CDGP.

⭐ Constitutional delay of growth and puberty (CDGP) is the most common cause of delayed puberty in boys, often presenting with short stature and delayed bone age.

Key Syndromes & Workup - Puberty Puzzles

Diagnostic Workup Overview:

• History & Physical Exam (Tanner staging, dysmorphic features)
• Bone Age X-ray
• Hormonal Assays: LH, FSH, Estradiol/Testosterone, GnRH stimulation test
• Karyotyping
• Imaging: Pelvic USG; MRI Brain (if indicated)

⭐ Streak gonads are characteristic of Turner Syndrome and carry a risk of gonadoblastoma if Y chromosome material is present (e.g., mosaicism).

High‑Yield Points - ⚡ Biggest Takeaways

• Precocious puberty: Sexual characteristics before age 8 (girls), 9 (boys).
• Central precocious puberty (CPP): GnRH-dependent, treat with GnRH analogs.
• Peripheral precocious puberty (PPP): GnRH-independent, e.g., McCune-Albright syndrome, adrenal/gonadal tumors.
• Delayed puberty: No sexual development by age 13 (girls), 14 (boys).
• Constitutional Delay (CDGP): Most common cause of delayed puberty, a diagnosis of exclusion.
• Kallmann syndrome: Delayed puberty with anosmia/hyposmia (GnRH deficiency).
• Turner syndrome (45,XO): Delayed puberty, ovarian dysgenesis, short stature in girls.