Differential Diagnosis for Amenorrhea

Amenorrhea, the absence of menstruation, can be caused by a variety of factors. The differential diagnosis can be organized into the following categories:

• Single Most Likely Diagnosis

  • Polycystic Ovary Syndrome (PCOS): This is often considered the most common cause of amenorrhea in women of reproductive age. PCOS is characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. It is associated with insulin resistance, obesity, and an increased risk of metabolic syndrome.

• Other Likely Diagnoses

  • Hypothalamic Amenorrhea: Caused by stress, excessive exercise, or significant weight loss, leading to a decrease in gonadotropin-releasing hormone (GnRH) secretion.
  • Thyroid Dysfunction: Both hyperthyroidism and hypothyroidism can disrupt the menstrual cycle, leading to amenorrhea.
  • Hyperprolactinemia: Elevated levels of prolactin can suppress GnRH, leading to amenorrhea. This can be caused by prolactinomas, thyroid disorders, or certain medications.
  • Premature Ovarian Failure (POF): Also known as premature ovarian insufficiency, this condition occurs when the ovaries stop functioning before the age of 40.

• Do Not Miss Diagnoses

  • Pituitary Tumors: Although rare, pituitary tumors (such as prolactinomas) can cause amenorrhea by disrupting normal pituitary function.
  • Craniopharyngioma: A type of brain tumor that can affect the hypothalamus and pituitary gland, leading to amenorrhea.
  • Sheehan Syndrome: Postpartum necrosis of the pituitary gland, which can occur after severe postpartum hemorrhage.
  • Asherman Syndrome: Intrauterine adhesions, often caused by uterine surgery, which can lead to amenorrhea.

• Rare Diagnoses

  • Congenital Adrenal Hyperplasia: A group of inherited disorders that affect the adrenal glands, leading to an imbalance of sex hormones and potentially causing amenorrhea.
  • Androgen Insensitivity Syndrome: A condition where an individual is genetically male but has a resistance to androgens, leading to the development of female external genitalia but with undescended testes and no uterus, resulting in primary amenorrhea.
  • Mayer-Rokitansky-Küster-Hauser (MRKH) Syndrome: A rare congenital disorder characterized by the absence or underdevelopment of the vagina and uterus, leading to primary amenorrhea.
  • Autoimmune Disorders: Certain autoimmune conditions, such as autoimmune oophoritis or thyroiditis, can lead to amenorrhea, although these are less common causes.