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Amenorrhea

Definition

Amenorrhea is the absence of menstruation when menstrual periods should occur:

  1. Primary amenorrhea:
    1. No menstrual period by age 14 years in the absence of growth or development of secondary sexual characteristics.
    2. No menstrual period by age 16 years regardless of the presence of normal growth and development with the appearance of secondary sexual characteristics.
  2. Secondary amenorrhoea: No menstrual period for six months in a woman who usually has normal periods, or for a length of time equal to three-cycle intervals in a woman with less-frequent cycles.

Incidence and Prevalence

Discussed in pathogenesis section

Pathogenesis

Likely not important for the NAC exam, but could be used for patient teaching. Pathogenesis discussion is also important for considering the DDx

(If you're a keener click here)
  1. Physiological: Pregnancy, breastfeeding, and menopause.
  2. Disorders of the central nervous system (CNS) which specifically affect hypothalamic function resulting in a deficiency of pulsatile GnRH secretion (most common cause of amenorrhea, 28%):
    1. Stress (10%).
    2. Weight loss 2/2 anorexia, bulimia (10%).
    3. Extreme exercise.
    4. Medications.
    5. Hormones.
    6. Hypothyroidism (10%).
    7. Major medical disease, e.g. Crohn's disease, SLE.
  3. Disorders of the outflow tract or uterine target organ (uncommon):
    1. Asherman’s syndrome from inadvertent endometrial ablation during dilation and curettage (7%).
    2. Agenesis or structural anomalies of the uterus, tubes, or vagina.
  4. Disorders of the ovary:
    1. With abnormal chromosomes, as in Turner's (0.5%)
    2. With normal chromosomes (10%), as in:
      1. Gonadal dysgenesis/agenesis.
      2. Premature ovarian failure.
      3. Premature menopause, before age 40.
      4. Chemotherapy, radiation, or chemotherapy.
      5. Polycystic ovarian disease
  5. Disorders of the anterior pituitary: Including prolactin-secreting tumours (7.5%).

Predisposing factors

  1. Any female susceptible aged 14 - 55.

Common Findings

Amenorrhea or oligomenorrhea.

Other Signs and Symptoms

  1. Irregular, infrequent menstrual periods.
  2. Galactorrhea.
  3. Pregnancy.
  4. Excessive hair growth.

History

  1. OB/GYN history:
    1. Complete menstrual history, including age of onset, duration/frequency/regularity, and dysmenorrhea.
    2. Obstetrical hx.
    3. Contraception/hormone use.
  2. ROS, including breast discharge, weight changes.
  3. Social history including self-image, stress, exercise pattern.

Physical Examination

Coming soon.

Diagnostic Tests

  1. Urine: Pregnancy test.
  2. Serum hCG, TSH, prolactin, FSH, LH
  3. Pelvic/vaginal ultrasound
  4. If primary amenorrhea, genetic analysis w/ karyotype.

DDx

Mainly centered around causes of amenorrhea:

  1. Pregnancy.
  2. Constitutional delay.
  3. Hypothyroidism.
  4. Polycystic ovarian syndrome.
  5. POF, or early menopause.
  6. Perimenopause.
  7. Pituitary adenoma.
  8. Androgen insensitivity syndrome.

Plan

  1. General interventions:
    1. If pregnant, menopause, counsel patient.
    2. Progesterone challenge test.
  2. Pharmacological therapy:
    1. Treat all anovulatory cycles d/t risk of unopposed estrogen which may lead to endometrial cancer.

Follow-up

Return in 6 months after hormone/progesterone therapy, 1 year if perimenopausal.

Consultation/Referral

Refer client if no withdrawal bleeding after challenge, or abnormal prolactin.


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