This 16-year-old female has never menstruated and, therefore, has primary amenorrhea. Furthermore, she has not yet experienced breast development (which should occur by age 14 years) and thus has delayed puberty. The lack of breast development means a lack of estrogen, which may be caused by either a CNS problem (low gonadotropin levels) or an ovarian problem (elevated gonadotropins). She is of short stature, confirming the lack of estrogen. The absent pubic and axillary hair is consistent with delayed puberty. The most likely diagnosis without further information would be gonadal dysgenesis, such as Turner's syndrome. An elevated FSH level would be confirmatory.
APPROACH TO PUBERTAL DELAY
See also Case 45. Definitions
Delayed puberty: Lack of secondary sexual characteristics by age 14 years.
Gonadal dysgenesis: Failure of development of ovaries, usually associated with a karyotypic abnormality (e.g.. 45.X) and often associated with streaked gonads.
Maturation of the hypothalaniic-pituitary-ovarian axis leads to the onset of puberty. There are four stages of pubertal development: 1) thelarche, 2) pubarche/adrenarche, 3) grow th spurt, and 4) menarche. The first sign of puberty is the appearance of breast budding (thelarche), which occurs at a mean age of 10.8 years. This is followed by the appearance of pubic and axillary hair (pubarche/adrenarche), usually at 11 years. The growth spurt typically occurs I year after thelarche. The onset of menses (menarche) is the final event of puberty, occurring approximately 2.3 years after thelarche, at a mean age of 12.9 years. Normal puberty takes place between the ages of 8 and 14 years, with an average duration of 4.5 yr. Delayed puberty is the absence of secondary sexual characteristics by age 14 years.
Thelarche —> Adrenarche —» Growth spurt —> Menarche
Breast bud Axillary & Pubic Menses
Delayed puberty can be subdivided based on two factors: the gonadotropic state and the gonadal state. The FSH level defines the gonadotropic state. The ovarian production of estrogen refers to the gonadal state. The FSH level differentiates between brain and ovarian causes of delayed puberty. CNS defects result in low FSH levels secondary to disruption of the hypothalamic-pituitary axis. With ovarian failure, the negative feedback of estrogen on the properly functioning hypothalamic-pituitary axis is not present, resulting in high FSH levels.
Hypergonadotropic hypogonadism (high FSH, low estrogen) is due to gonadal deficiency. The most common cause of this type of delayed puberty is Turner's syndrome. These individuals have an abnormality in or absence of one of the X chromosomes, leading to gonadal dysgenesis and a 45,X karyotype. They do not have true ovaries; rather, they have a fibrous band of tissue referred to as gonadal streaks. Thus, they lack ovarian estrogen production and, as a result, secondary sexual characteristics. The internal and external genitalia are those of a normal female but remain infantile even into adult life. Other characteristic physical findings are short stature, webbed neck, shield chest, and increased carrying angle at the elbow. Turner's syndrome should be suspected in an individual who presents with primary amenorrhea, prepubescent secondary sexual characteristics, and sexually infantile external genitalia. The definitive diagnosis can be made with an elevated FSH level and a karyotypic evaluation. Other causes of hypergonadotropic hypogonadism are ovarian damage due to exposure to ionizing radiation, chemotherapy, inflammation, or torsion.
Hypogonadotropic hypogonadism (low FSH, low estrogen) usually is secondary to a central defect. Hypothalamic dysfunction may occur due to poor nutrition or eating disorders (anorexia nervosa, bulimia), extremes in exercise, and chronic illness or stress. Other causes are primary hypothyroidism, Cushing's syndrome, pituitary adenomas, and craniopharyngiomas (the most commonly associated neoplasm).
The diagnostic approach to delayed puberty begins with a meticulous history and physical examination. The history should query chronic illnesses, exercise and eating habits, and age at menarche of the patient's sisters and mother. The physical examination should search for signs of chronic illness, such as a goiter, or neurologic deficits, such as visual field defects indicative of cranial neoplasms. Skull imaging should be obtained to look for intracranial lesions. Laboratory evaluation should include serum measurements of FSH, prolactin, thyroid-stimulating hormone (TSH), free thyroxine (T4), and appropriate adrenal and gonadal steroids. Karyotype evaluation should be performed when the FSH level is elevated.
The management goals for patients with delayed puberty are to initiate and sustain sexual maturation, prevent osteoporosis from hypoestrogenemia, and promote the full height potential. Hormonal therapy can be used to achieve these objectives. Combination oral contraceptives provide the small amounts of estrogen needed to promote growth and development, and the progestin protects against endometrial cancer.
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