2. Prolactin is most accurately obtained in a patient who is fasting and who has not had any recent breast stimulation to avoid concluding that a patient is hyperprolactinemic on the basis of a transient prolactin elevation. If a patient still has some menstrual cycles, it is advisable to obtain the prolactin level in the follicular phase.
Assessment of serum FSH levels is required to determine whether the patient has hypergonadotropic, hypogonadotropic, or eugonadotropic amenorrhea. A circulating FSH level of greater than 25 to 40 mIU/mL indicated on at least two blood samples is indicative of hypergonadotropic amenorrhea. Hypergonadotropism implies that the cause of amenorrhea is ovarian insufficiency. The history should establish whether the cause of ovarian insufficiency is chemotherapy or radiation therapy.
One test that is likely to be performed increasingly frequently is serum AMH. AMH is a product of the granulosa cells. AMH levels are low in women with POI and high in women with PCOS. AMH may be used more commonly in the evaluation of amenorrhea, but its assessment is not yet part of routine evaluation.
If the diagnosis of POI is confirmed, the patient should be tested for: 1. FMR1 premutation 2. Karyotype 3. 21-hydroxylase antibody.
FMR1 premutation testing will reveal women at risk for bearing a child with fragile X syndrome, which may be important information for other family members. The goal of the peripheral blood karyotype is to identify an absent or abnormal X chromosome and to identify whether or not any portion of a Y chromosome is present. In situ hybridization studies may prove the existence of Y chromosomal material with a Y-specific probe when the karyotype is normal and should be assessed if there are clinical signs to suggest that a Y-bearing cell line is present despite normal routine peripheral blood karyotype (125). It is important to identify Y chromosomal material so it may be removed to prevent malignant degeneration. Although commonly suggested that
Assessment of the Pituitary and Hypothalamus karyotype only be performed if the patient is under age 30, it should be noted that rare patients with Turner syndrome developed amenorrhea after age 35. In addition, some patients who present over the age of 30 may have actually had the onset of POI at a younger age but were unaware because of the use of oral contraceptives. Therefore, consideration should be given to performance of karyotype, regardless of the patient’s age. Testing for 21-hydroxylase antibody will identify women at risk for adrenal crisis.
If a diagnosis of PCOS is suspected, the patient should have: 1.
Documentation of hyperandrogenism (either by serum total testosterone and sex hormone binding globulin or free testosterone and/or by presence of physical findings such as acne, hirsutism, and androgenic alopecia), 2.
Serum 17-hydroxyprogesterone to exclude congenital adrenal hyperplasia resulting from 21-hydroxylase deficiency, particularly if the patient is at increased risk (highest prevalence is among Ashkenazi Jews, Hispanics, Yugoslavs, Native American Inuits in Alaska, and Italians) (79), 3.
If the diagnosis of PCOS is made, the patient should undergo a 2-hour oral glucose tolerance test and a fasting lipid profile.
If the patient is hypoestrogenic and the FSH level is not high, pituitary and hypothalamic lesions should be excluded.
1.
A complete neurologic examination may help localize a lesion.
2.
Either CT or MRI scanning should be performed to confirm the presence or absence of a tumor. MRI will identify smaller lesions than CT; if a lesion is too small for identification by CT, it may be clinically insignificant. MRI offers the advantage of avoiding exposure to x-ray.
3.