Differentials
Pregnancy
SIGNS / SYMPTOMS
History of unprotected intercourse.
INVESTIGATIONS
Serum or urine human chorionic gonadotropin (HCG): positive.
Polycystic ovary syndrome
SIGNS / SYMPTOMS
Slowly progressive symptoms, obesity, hirsutism, acne, deepening of voice, male pattern hair growth or loss, oily skin, weight gain, oligoanovulatory cycles to amenorrhea (if peripubertal onset, may present with delayed menarche), history of premature pubarche, androgenic alopecia, acanthosis nigricans, increased waist-hip ratio, clitoromegaly.
INVESTIGATIONS
Serum human chorionic gonadotropin (HCG): negative; serum follicle-stimulating hormone: normal; serum estradiol: normal to elevated; serum anti-Müllerian hormone: elevated; serum thyroid-stimulating hormone: normal; serum prolactin: normal; serum dehydroepiandrosterone sulfate: elevated; total serum testosterone: elevated, marked elevation suggests ovarian/adrenal tumor; pelvic ultrasound: polycystic ovaries, variable endometrial stripe.
Anorexia nervosa
SIGNS / SYMPTOMS
Low BMI (10% less than ideal body weight), normal secondary sexual characteristics, normal external and internal genitalia.
INVESTIGATIONS
Serum human chorionic gonadotropin (HCG): negative; serum follicle-stimulating hormone (FSH): low to normal (FSH assays have wide ranges, depending not only on cycle time but also on patient age); serum estradiol: low; serum anti-Müllerian hormone: low to normal; serum thyroid-stimulating hormone: normal; serum prolactin: normal; pelvic ultrasound: thin endometrial stripe.
Strenuous exercise
SIGNS / SYMPTOMS
Weight loss, anorexia, sleep disturbances, dry skin, prescription drugs, normal secondary sexual characteristics, normal external and internal genitalia.
INVESTIGATIONS
Low BMI (10% less than ideal body weight); serum human chorionic gonadotropin (HCG): negative; serum follicle-stimulating hormone (FSH): low to normal (FSH assays have wide ranges, depending not only on cycle time but also on patient age); serum estradiol: low; serum thyroid-stimulating hormone: normal; serum prolactin: normal; pelvic ultrasound: thin endometrial stripe.
Emotional or physical stress
SIGNS / SYMPTOMS
Weight loss, anorexia, sleep disturbances, dry skin, prescription drugs, normal secondary sexual characteristics, normal external and internal genitalia.
INVESTIGATIONS
Low BMI (10% less than ideal body weight); serum human chorionic gonadotropin (HCG): negative; serum follicle-stimulating hormone (FSH): low to normal (FSH assays have wide ranges, depending not only on cycle time but also on patient age); serum estradiol: low; serum thyroid-stimulating hormone: normal; serum prolactin: normal; pelvic ultrasound: thin endometrial stripe.
Sheehan syndrome
SIGNS / SYMPTOMS
Severe obstetric hemorrhage, hypotension, and shock with postpartum panhypopituitarism (after volume and blood resuscitation), nausea, vomiting, lethargy, failure to breastfeed, slowed mental function, fatigue, weight loss, delayed symptoms of hypothyroidism, postural hypotension, loss of axillary and pubic hair, adrenal crisis (with skin depigmentation), rapidly involuting breasts, periorbital edema.
INVESTIGATIONS
Serum human chorionic gonadotropin (HCG): negative; serum follicle-stimulating hormone: low; serum estradiol: low; serum thyroid-stimulating hormone: low; serum thyroxine: low; serum prolactin: low; serum growth hormone: low; serum adrenocorticotropic hormone: low to normal; serum sodium: may be low; serum cortisol (morning): may be low; MRI brain: sella empty or filled with cerebrospinal fluid, pituitary gland may be small; pelvic ultrasound: thin to variable endometrial stripe.
Androgen-producing ovarian tumor
SIGNS / SYMPTOMS
Rapidly progressive symptoms, obesity, hirsutism, acne, deepening voice, male pattern hair growth or loss, oily skin, weight gain, oligoanovulatory cycles to amenorrhea; androgenic alopecia, clitoromegaly, male pattern hair growth, increased muscle mass.
INVESTIGATIONS
MRI abdomen and pelvis would show an ovarian mass; free serum testosterone: elevated; total serum testosterone: elevated (<200 nanograms/dL); serum dehydroepiandrosterone sulfate: normal; serum follicle-stimulating hormone, luteinising hormone, thyroid-stimulating hormone, and prolactin: normal; serum estradiol: normal to elevated.
Hyperprolactinemia
SIGNS / SYMPTOMS
Galactorrhea (some patients), headache or visual disturbances (prolactinoma); may present with infrequent or reduced menstrual bleeding if prolactin levels are not extremely elevated; visual field deficit (some patients).
INVESTIGATIONS
MRI brain may show pituitary tumor; serum prolactin: elevated; >100 nanograms/mL is highly suggestive of prolactinoma; serum follicle-stimulating hormone and luteinising hormone: low to normal; serum estradiol: low.
Medication-induced amenorrhea
SIGNS / SYMPTOMS
Antipsychotic medications are known to increase the risk of hyperprolactinemia and menstrual irregularities due to lessened inhibition by dopamine.
INVESTIGATIONS
Clinical diagnosis.
Congenital adrenal hyperplasia (nonclassic)
SIGNS / SYMPTOMS
Presents in late childhood to early adult life; obesity, hirsutism, acne, weight gain, history of premature pubarche; androgenic alopecia.
INVESTIGATIONS
Serum 17-hydroxyprogesterone (17-OHP) fasting levels >200 nanograms/dL; total serum testosterone: elevated; free serum testosterone: elevated; serum dehydroepiandrosterone sulfate: elevated; serum follicle-stimulating hormone, luteinising hormone, thyroid-stimulating hormone, and prolactin: normal; serum estradiol: normal to elevated.
Primary amenorrhea
SIGNS / SYMPTOMS
Lack of menses by age 15 years in a patient with appropriate development of secondary sexual characteristics, or absent menses by age 13 years and no other pubertal maturation.
INVESTIGATIONS
Assessment begins with clinical features (assessment of breast development and hair patterns), follicle-stimulating hormone testing, and presence or absence of normal female reproductive tract on ultrasound. At times, a karyotype and/or serum testosterone measurements may be helpful.
Turner syndrome
SIGNS / SYMPTOMS
Physical features include short stature, webbed neck, cubitus valgus (increased carrying angle of arms), and lack of sexual development at puberty.
INVESTIGATIONS
Karyotype of Turner syndrome is 45,XO.
Asherman syndrome
SIGNS / SYMPTOMS
Amenorrhea or light, but regular, periods.
No signs of hypoestrogenism.
History of endometrial curettage or severe postpartum hemorrhage.
INVESTIGATIONS
Transvaginal ultrasound, saline sono-contrast sonography, or hysteroscopy shows scar formation.
Hypothyroidism
SIGNS / SYMPTOMS
Frequently insidious onset of fatigue, goiter, exophthalmos, lid lag, bradycardia, or skin changes.
INVESTIGATIONS
Low free thyroxine, elevated thyroid-stimulating hormone.
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