Disorders of Puberty

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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. Tanner Stages of Pubertal Development

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

SyndromeKaryotypeKey Features
Turner Syndrome45,X0Short stature, webbed neck, shield chest, ovarian dysgenesis, coarctation aorta
Klinefelter Synd.47,XXYTall stature, gynecomastia, small firm testes, infertility
Kallmann Synd.VariableHypogonadotropic hypogonadism, anosmia/hyposmia

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.

Practice Questions: Disorders of Puberty

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A physician is evaluating a patient with hypogonadotropic hypogonadism and anosmia. What condition is most likely suspected in this scenario?

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Flashcards: Disorders of Puberty

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What type of precocious puberty is more common?_____

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What type of precocious puberty is more common?_____

Central

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