A1. Amenorrhea; classifications, diagnosis and therapy

Amenorrhoea means that there is a loss of menstruation. We can distinguish primary and secondary amenorrhea.

Primary amenorrhoea

Primary amenorrhea is the failure of menstruation to occur by age 16, despite normal growth and secondary sexual characteristics, or by the age of 14 if there are no secondary sexual characteristics.

Etiology

• Hypergonadotropic hypogonadism
  • Gonadal dysgenesis – (most common cause)
• Anatomical abnormalities of the genital tract
  • Müllerian agenesis
  • Hymen imperforatum
  • Vaginal septum
• Hypogonadotropic/hypothalamic hypogonadism
  • Constitutional delay
  • Pituitary tumour
  • Kallmann syndrome (anosmia + primary amenorrhoea)
  • Functional hypothalamic amenorrhoea
• Androgen insensitivity syndrome
• All causes of secondary amenorrhoea can also cause primary amenorrhoea (if they occur early enough)

Gonadal dysgenesis refers to conditions characterised by the absence of germ cells in the gonads. The most common types are Turner syndrome (45 XO), 46 XX ovarial dysgenesis, and 46 XY gonadal dysgenesis (Swyer syndrome).

Müllerian agenesis, also known as Mayer-Rokitansky-Küster-Hauser syndrome or MRKH syndrome, is a syndrome characterised by failed fusion of Müllerian ducts. This causes the uterus, cervix, and upper third of the vagina to be atretic.

Hypogonadotropic/hypothalamic hypogonadism refers to those conditions where there is decreased GnRH, which causes hypogonadism.

Kallmann syndrome is a special cause of hypogonadotropic hypogonadism, which is characterised by anosmia and primary amenorrhoea. It occurs due abnormal olfactory nerve fibres, which GnRH-releasing neurons are dependant on to migrate from the nasal region to the hypothalamus.

Constitutional delay refers to normal physiological pubertal development but with adrenarche and gonadarche occuring at a later age than normal. There is no pathology involved.

Androgen insensitivity syndrome (AIS) is due to a mutation in the androgen receptor which makes them defective. As a result, this 46XY person becomes insensitive to androgens, thereby acquiring a female phenotype.

Diagnosis and evaluation

It’s important to measure the following:

• History taking
• Physical examination, especially of the breasts
  • The presence of breasts is a marker of oestrogen action and therefore function of the ovary
• Pelvic ultrasound – to look for uterine, cervical, and/or vaginal abnormalities or absences
• FSH
  • Low FSH is due to abnormality of the hypothalamus/pituitary
  • High FSH is due to decreased negative feedback on the hypothalamus/pituitary, due to abnormal gonads
• hCG – to rule out pregnancy
• Karyotyping

If breasts are present, the following disorders are most likely:

• Androgen insensitivity syndrome
• Anatomical abnormalities of the genital tract
  • Müllerian agenesis
  • Hymen imperforatum
  • Vaginal septum

In Müllerian agenesis and androgen insensitivity syndrome the absence of the uterus can be determined by ultrasound. Vaginal septum and imperforate hymen can be diagnosed with transvaginal, translabial or transabdominal ultrasound.

If breasts are absent and the FSH is high, gonadal dysgenesis (like Turner syndrome) is most likely. Karyotyping should be performed to diagnose them.

If breasts are absent and the FSH is low, the following disorders are most likely:

• Hypogonadotropic/hypothalamic hypogonadism
  • Constitutional delay
  • Pituitary tumour
  • Kallmann syndrome (anosmia + primary amenorrhoea)
  • Functional hypothalamic amenorrhoea

Prolactin level can rule out prolactinoma. Anosmia indicates Kallmann syndrome. Imaging can rule out CNS tumours.

Treatment

Treatment involves management of the underlying cause. Anatomical abnormalities must be treated by surgery. For more information on treating intersexual conditions, see topic B5.

Secondary amenorrhoea

Secondary amenorrhoea is the loss of menstruation for 3 – 6 months or more in a person who have previously had normal menstrual cycles.

Etiology

• Pregnancy – (most common cause)
• Ovarian insufficiency
  • Polycystic ovary syndrome
  • Primary ovarian insufficiency
• Hypo/hyperthyroidism
• Hyperprolactinaemia
  • Antipsychotics
  • Prolactinoma
• Hypopituitarism (pituitary amenorrhoea)
  • Sheehan syndrome
  • Panhypopituitarism (Simmonds syndrome)
  • Brain irradiation
• Functional hypothalamic amenorrhea
  • Excessive exercise
  • Anorexia nervosa
  • Stress
• Asherman syndrome

Asherman syndrome refers to the presence of intrauterine adhesions. This is most commonly secondary to uterine surgery, but may also occur after PID or IUD.

Diagnosis and evaluation

The following investigations are important:

• History taking
• Physical examination
• hCG
• FSH
• TSH
• Prolactin
• Oestradiol

Pregnancy is the most common cause, so hCG must be measured.

Elevated FSH or LH indicates ovarian insufficiency (due to decreased negative feedback).

Elevated TSH indicates hypothyroidism.

If a CNS cause is supected MRI/CT should be performed.

Normal/low LH and FSH with low oestradiol suggest hypothalamic or pituitary failure.

Treatment

Treatment involves management of the underlying cause.

Hyperprolactinaemia can be treated with dopamine agonists like bromocriptine or cabergoline.