History

Particular features of the history are important to elicit in order to evaluate a possible cause for delayed puberty and amenorrhea. Past history of intercurrent illness, weight change, and psychological stress can all influence progression through puberty. More subtle changes in dietary restriction or sporting activities can also affect hypothalamic function. Most adolescents will have a clear view of how they compare with their peer group in terms of growth and development and may even be able to identify an age when they departed from the norm. Family histories regarding the development of a sibling can also be informative.

Examination

First, a thorough assessment of auxology should be preformed with height, weight, and pubertal staging plotted against standard reference charts. Included in this assessment is the predicted height based on parent’s stature. Short stature is a feature of several conditions presenting with primary amenorrhea including Turner’s syndrome, hypopituitarism, and CHARGE syndrome (coloboma, heart defects, atresia choanae (also known as choanal atresia), growth retardation, genital abnormalities, and ear abnormalities). Tall stature may indicate the presence of a Y-chromosome as in Swyer syndrome, or in the older age group of delayed closure of the epiphyses as a result of estrogen deficiency. Low body weight or excessive exercise is a risk factor for hypothalamic amenorrhea with overweight being more common in PCOS. There are two components to pubertal stage. The function of estrogens is determined by Tanner staging breast development. The function of androgens is based on sexual hair development. With regard to primary amenorrhea, it is useful to contrast those with delayed or absent puberty as an estrogen-deficient subgroup from those with normal breast development as being estrogen replete, accepting there is a degree of overlap between the two.

Signs of hyperandrogenism, acne, hirsutism, and alopecia are suggestive of PCOS, although biochemical testing may be required to differentiate other causes of androgen excess. The most common is late onset congenital adrenal hyperplasia. It is important to distinguish between hyperandrogenism and virilization, which also occurs with high circulating androgen levels and causes deepening of the voice, breast atrophy, increase in muscle bulk, and cliteromegaly. A rapid onset of hirsutism suggests the possibility of an androgen-secreting tumor of the ovary or adrenal gland. Hirsutism can be graded and given a Ferriman Gallwey Score by assessing the amount of hair in different parts of the body (e.g., upper lip, chin, breasts, abdomen, arms, legs) taking into account ethnic variations in the expression of hirsutism. Acanthosis nigricans (AN) is a sign of profound insulin resistance and is usually visible as hyperpigmented thickening of the skin folds of the axilla and neck; AN is associated with PCOS and obesity.

Vaginal examination is rarely required in the assessment of primary amenorrhea and should only be undertaken by an experienced adolescent gynecologist.

Endocrine Laboratory Investigation

The vast majority of cases of primary amenorrhea can be assessed with a simple initial profile composed of LH, FSH, prolactin, estradiol, and thyroid function [6,7]. A measurement of testosterone can be added in those with hyperandrogenism. In those with absent or delayed puberty, a measurement of FSH will distinguish between those with hypothalamic or pituitary conditions and those with gonadal dysgenesis (Figure 8B.1). Table 8B.2 lists reference values for endocrine investigations.

Figure 8B.1 Algorithm for the diagnosis of primary amenorrhea. Note the subgrouping based on estrogen status (breast development) and the FSH measurement. (AIS – androgen insensitivity syndrome; FSH – follicle stimulating hormone; PCOS – polycystic ovary syndrome.)

A measurement of total testosterone (T) is considered adequate for general screening of hyperandrogenism. It is unnecessary to measure other androgens unless total T is >5 nmol/L (this will depend on the normal range of your local assay). Insulin may be elevated in overweight girls and suppresses the production of sex hormone binding globulin (SHBG) by the liver, resulting in a high free androgen index (FAI) in the presence of a normal total T. The measurement of SHBG is not always required in routine practice but is a useful marker for insulin resistance (IR).

A testosterone concentration > 5 nmol/L should be investigated to exclude androgen-secreting tumors of the ovary or adrenal gland, Cushing’s syndrome, and late-onset congenital adrenal hyperplasia (CAH). Whereas classical salt-losing CAH often presents at birth with ambiguous genitalia, partial 21-hydroxylase deficiency may present in later life, usually in the teenage years, with signs and symptoms similar to PCOS. In such cases, T may be elevated and the diagnosis confirmed by an elevated serum concentration of 17-hydroxyprogesterone (17-OHP); an abnormal ACTH-stimulation test may also be helpful (250 µg ACTH will cause an elevation of 17-OHP, usually between 65 and 470 nmol/L).

The measurement of other serum androgens is only required in cases of severe hyperandrogenism, particularly those that are rapidly progressive. Dehydroepiandrosterone sulphate (DHEAS), a product of the adrenal androgen pathway, is also raised in 10 percent of women with PCOS. The measurement of androstenedione can also be useful in some situations with the benefit, in contrast to testosterone, that it is not strongly bound to SHBG.

Raised prolactin is a rare cause of primary amenorrhea; care must be taken in the interpretation of this result because this is a volatile marker of stress that can result from examination or phlebotomy. Thyroid function is included in the work-up for primary amenorrhea even though it is also a rare cause in this age group. Anti Mullerian hormone (AMH) measurements are rarely required in this age group, where AMH reflects ovarian maturation rather than ovarian reserve for which it is useful in women older than age 30 [8].

Dynamic testing of the hypothalamus using GnRH has a degree of discriminatory power to differentiate constitutional delay of puberty from hypogonadatrophic hypogonadism. Individuals with severe gonadotropin deficiency have an impaired response to GnRH stimulation; therefore, induction of puberty can be started without delay whereas those with constitutional delay may benefit from a strategy of watchful waiting.

Karyotype is only required for those presenting with raised FSH or absent uterus on ultrasound. The identification of single gene defects that cause hypogonadatrophic hypogonadism is not routinely available, although it may become so in the future [9,10]. Fragile X permutation screening is advised for ovarian insufficiency.

Endocrine Assessment with Pelvic Ultrasound

Pelvic ultrasound is an important endocrine assessment when investigating primary amenorrhea [11]. The ultrasound examination is carried out abdominally rather than vaginally; so it is essential that a sonographer experienced in transabdominal scanning performs the examination.

The size and shape of the uterus is a guide to ambient estrogen status and are generally more informative than serum estradiol concentrations that are often at the lower limit of detection [12]. In the prepubertal uterus, the cervix is the most prominent feature with a relatively small uterine body. With progression through puberty, the fundus gradually dominates both in length and later in transverse diameter. Later in puberty, the endometrial thickness is a useful guide to estrogen status. It is important to note that in the absence of estrogen, the uterus may appear to be absent. Therefore, no pronouncement can be made regarding the presence of a uterus until a therapeutic trial of estrogen has been undertaken for at least 3 months [13].

The morphology of the ovary has to be interpreted with caution in individuals with primary amenorrhea. During puberty, the ovary passes through a multifollicular phase that can easily be confused with a polycystic morphology.

The morphology of the polycystic ovary has been defined as an ovary with 12 or more follicles measuring 2–9 mm in diameter and/or an increased ovarian volume (>10 cm³) [14], although there has been subsequent data to suggest the need for >25 follicles using the latest high-definition ultrasound scanners and young women inherently have more follicles [15].