• Clinical science

Puberty

Summary

Puberty refers to the phase of development between childhood and adulthood in which complete functional maturation of the reproductive glands and external genitalia occurs. The other processes that characterize this transitional phase are the development of secondary sex characteristics, growth spurts, and psychosocial changes. The stages of development during puberty are classified according to the Tanner stages. Although there is considerable variation between individuals, puberty begins on average at the age of 11 in girls and 13 in boys. When puberty begins abnormally early it is referred to as precocious puberty and is classified into two main types: peripheral precocious puberty, which is independent of gonadotropin-releasing hormone secretion; and central precocious puberty, which involves the hypothalamo-hypophyseal axis. At the other end of the disease spectrum, puberty may be delayed or absent. This delay can be constitutional (most common), secondary to underlying conditions, or due to hypogonadism.

Normal puberty

Definition

  • A phase of development between childhood and complete, functional maturation of the reproductive glands and external genitalia (adulthood)

Phases of pubertal changes

The age of pubertal onset may vary, but the order of changes that occur in each person is consistent.

Physiology

Influential factors

  • General health (nutritional state, bodyweight) [1]
  • Genetics
  • Social environment (e.g., family stress)

Girls

  • Normal age of onset: 8–13 years
  • Normal order of changes: adrenarche gonadarche thelarche (age of onset 8–11 years) growth spurt (age of onset 11.5–16.5 years) → pubarche (mean age of onset 12 years) → menarche (age of onset 10–16 years, mean age: 13 years) [2]

Boys

  • Normal age of onset: 9–14 years
  • Normal order of changes: adrenarche gonadarche (age of onset 9–14 years) → pubarche (mean age of onset 13.5 years) growth spurt (mean age of onset 13.5 years)→ androgenic hair growth

The first visible sign of puberty in males is testicular enlargement, while in females it is breast development.

Physical changes during puberty

Tanner stages

Tanner Stages Breast development (girls)
B1
  • Prepubertal appearance and size
  • Occasional elevation of the nipple
B2
B3
B4
B5
  • Adult breast
  • Areola with projection of papilla only
Genital development (boys)
G1
G2
  • Testicular volume of 4 mL
  • Larger scrotum
  • Penile growth has not begun
  • Scrotal skin changes darkens in color and texture
G3
  • Continued enlargement of the testes and scrotum
  • Penile growth begins
G4
  • Testicular volume of 12 mL
  • Scrotum growth
  • Penile growth continues: longer and wider penis
  • Development of penis glans
G5
Pubic hair development (boys and girls)
Ph1
  • Usually no pubic hair, vellus hair possible
Ph2
  • Sparse, lightly pigmented hair (straight or curled) on the labia/base of the penis
Ph3
Ph4
  • Adult pubic hair that does not extend to the inner thighs
Ph5
  • Adult pubic hair that extends to the inner thighs with horizontal upper border
Ph6

Other morphological changes during puberty [3][4][5]

  • Breast development (boys)
    • Occurs approximately within 18 months of pubertal onset in males
    • Usually during Tanner stage 3
    • Lasts for ∼ 6–18 months
    • Gynecomastia is diagnosed in a pubertal male when the palpable subareolar gland and ductal tissue is ≥ 2 cm (see “Pubertal gynecomastia”).
  • Growth spurt
    • Linear growth is approx. 5 cm/year from 4 years of age to puberty
    • Varies between the sexes, generally occurs between ages 13–15 years (in girls, it can begin two years earlier).
    • Includes ↑ growth in trunk and limbs
    • Assessed using growth velocity charts
    • It generally lasts ∼ 2 years, girls complete it at age 15 and boys at age 17.
  • Bone growth
  • Bodyweight and composition
    • Boys: initial ↓ body fat (early puberty) → ↑ lean body mass (late puberty)
    • Girls: gradual increase in body fat
    • Affected by nutritional status
  • Dermatological changes [6]
  • Myopia: due to axial growth of the eye
  • Other physical changes associated with menarche: anemia

Stages of adolescence

Adolescence is the period of physical, cognitive, and psychosocial development from the onset of puberty to adulthood (age of majority).

Stage of adolescence [7][8]

Onset Features
Early
  • 10–14 years
Middle
  • 15–16 years
  • Physical growth continues for males, but slows down for females
  • Menarche, spermarche
  • Development of an independent identity
  • Increased drive to become independent
  • Interested in moral reasoning
  • Increased health risk (e.g., smoking, drugs, alcohol)
Late
  • ≥ 17 years
  • End of puberty changes
  • Further development of identity
  • Development closer relationships with individuals
  • Rational thinking
  • Awareness of the future

Precocious puberty

Definition [9]

Epidemiology [3][10]

  • Incidence: 1:5,000 to 1:10,000 children
  • Ten times more common in girls than boys.

Classification

Central precocious puberty [3][9][11]

Definition

Etiology

Pathophysiology

Clinical features

Diagnosis

  • Laboratory tests
  • Imaging
    • X-ray of the left hand and wrist: allows comparison between skeletal maturation and chronological age
      • Assess and confirm accelerated bone growth.
      • Bone age is within 1 year of a child's age: Puberty likely has not started.
      • Bone age is > 2 years of the child's age: Puberty has been present for a year or longer.
    • MRI/CT of the brain with contrast: when LH is confirmed
      • Perform in girls ≤ 6 years of age, all boys, and children with neurologic symptoms.
      • Rule out intracranial causative pathology.

Treatment

  • GnRH agonist (e.g., leuprolide, buserelin, goserelin): to prevent premature fusion of growth plates
    • Close monitoring of therapy
    • Follow-up is recommended every 4–6 months to assess progression.
  • Manage underlying cause.

Peripheral precocious puberty [12][3][9][11]

Definition

Etiology

Clinical features

Diagnosis

Treatment

Central precocious puberty has a central cause (e.g., hypothalamic lesions) and high GnRH levels, while peripheral precocious puberty has a peripheral cause (e.g., germ cell tumors), without elevated GnRH levels.

Benign pubertal variants [11]

Obesity-related precocious sexual development [13][14][15]

McCune-Albright syndrome

Definition [16]

Epidemiology

  • Accounts for 5% of cases of precocious puberty (more common in females) [17]
  • Affects 1 in 100,000 to 1 in 1,000,000 individuals in the general population [17]
  • Peak incidence: early childhood

Etiology

Pathophysiology [18]

Clinical features [16]

Diagnostics [19][16]

Treatment

Differential diagnosis

The 3 P's of McCune-Albright syndrome are Polyostotic fibrous dysplasia, Pigmentation (café-au-lait spots), and Precocious puberty.

Delayed onset of puberty

Definition [20][21][22]

Etiology [22][23]

Clinical features

Diagnosis [22][23]

Treatment [23]

  • Constitutional growth delay: expectant management
    • No treatment is needed as catch-up growth eventually occurs and the individual reaches a normal adult height.
    • Serial growth measurements at frequent intervals (∼ every 6 months)
    • Reassuring the child and parents is sufficient.
  • Other pathologies

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last updated 11/25/2020
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