Differential Diagnosis for Infertility in a 28-year-old Nulligravid Woman
Single Most Likely Diagnosis
- Hypothalamic Amenorrhea: This condition is characterized by irregular or absent menstrual periods due to a problem with the hypothalamus, a part of the brain that regulates hormones. The patient's history of frequent missed periods, negative home pregnancy tests, and normal pelvic ultrasonography supports this diagnosis. The low estradiol level (<10 pg/mL) also suggests a problem with ovarian function, which can be secondary to hypothalamic dysfunction.
Other Likely Diagnoses
- Polycystic Ovary Syndrome (PCOS): Although the patient does not have excess hair on physical examination, PCOS can present with irregular menstrual cycles and infertility. However, the normal testosterone and dehydroepiandrosterone sulfate levels make this diagnosis less likely.
- Thyroid Dysfunction: The patient's TSH level is within the normal range, but some studies suggest that even mild thyroid dysfunction can affect fertility. Further evaluation of thyroid function may be necessary.
- Pituitary Dysfunction: The patient's prolactin level is within the normal range, but a pituitary tumor or other pituitary dysfunction could cause infertility and irregular menstrual cycles.
Do Not Miss Diagnoses
- Pituitary Adenoma: A pituitary adenoma can cause infertility, irregular menstrual cycles, and headaches (which could be mistaken for migraines). Although the patient's prolactin level is normal, a non-functioning pituitary adenoma could still be present.
- Ovarian Failure: Premature ovarian failure can cause infertility and irregular menstrual cycles. Although the patient's FSH level is low, ovarian failure should be considered, especially if other diagnoses are ruled out.
Rare Diagnoses
- Congenital Adrenal Hyperplasia: This rare genetic disorder can cause infertility, irregular menstrual cycles, and excess hair growth (although the patient does not have excess hair). The normal testosterone and dehydroepiandrosterone sulfate levels make this diagnosis less likely.
- Asherman's Syndrome: This rare condition, characterized by scarring in the uterus, can cause infertility and irregular menstrual cycles. However, the patient's pelvic ultrasonography shows a normal uterus, making this diagnosis less likely.