Amenorrhoea - Classification

Classification

There are two primary ways to classify amenorrhoea. Types of amenorrhoea are classified as primary or secondary, or based on functional "compartments" (Speroff). The latter classification relates to the hormonal state of the patient that could be hypo-, eu-, or hypergonadotropic (meaning FSH levels are either low, normal or high).

  • By primary vs. secondary: Primary amenorrhoea is the absence of menstruation in a woman by the age of 16. As pubertal changes precede the first period, or menarche, women by the age of 14 who still have not reached menarche, plus having no sign of secondary sexual characteristics, such as thelarche or pubarche—thus are without evidence of initiation of puberty—are also considered as having primary amenorrhoea. Secondary amenorrhoea is where an established menstruation has ceased—for three months in a woman with a history of regular cyclic bleeding, or nine months in a woman with a history of irregular periods. This usually happens to women aged 40–55. Amenorrhoea may cause serious pain in the back near the pelvis and spine. This pain has no cure, but can be relieved by a short course of progesterone to trigger menstrual bleeding.
  • By compartent: The reproductive axis can be viewed as having four compartments: 1. outflow tract (uterus, cervix, vagina), 2. ovaries, 3. pituitary gland, and 4. hypothalamus. Pituitary and hypothalamic causes are often grouped together.
P/S Outflow tract anomalies/obstruction Gonadal/end-organ disorders Pituitary and hypothalamic/central regulatory disorders
Overview The hypothalamic-pituitary-ovarian axis is functional. The ovary or gonad does not respond to pituitary stimulation. Gonadal dysgenesis or premature menopause are possible causes. Chromosome testing is usually indicated in younger individuals with hypergonadotropic amenorrhoea. Low oestrogen levels are seen in these patients and the hypo-oestrogenism may require treatment. Generally, inadequate levels of FSH lead to inadequately stimulated ovaries which then fail to produce enough oestrogen to stimulate the endometrium (uterine lining), hence amenorrhoea. In general, women with hypogonadotropic amenorrhoea are potentially fertile.
FSH Outflow tract abnormalities tend to be normogonadotropic and FSH levels are in the normal range. Gonadal, usually ovarian, abnormalities tend to be linked to elevated FSH levels or hypergonadotropic amenorrhoea. FSH levels are typically in the menopausal range. Both hypothalamic and pituitary disorders are linked to low FSH levels leading to hypogonadotropic amenorrhoea.
Primary
  • Uterine: Mullerian agenesis (Second most common cause, 15% of primary amenorrhoea)
  • Vaginal: Vaginal atresia, cryptomenorrhoea, imperforate hymen.
  • Gonadal dysgenesis, including Turner syndrome, is the most common cause.
  • Androgen insensitivity syndrome (Testicular feminization syndrome)
  • Receptor abnormalities for hormones FSH and LH
  • Specific forms of congenital adrenal hyperplasia
  • Swyer syndrome
  • Galactosaemia
  • Aromatase deficiency
  • Prader-Willi syndrome
  • Male pseudo-hermaphroditism (about 1 in every 150,000 births)
  • Other intersexed conditions
Secondary
  • Intrauterine adhesions (Asherman's syndrome)
  • Pregnancy (most common cause)
  • Anovulation
  • Menopause
  • Premature menopause
  • Polycystic ovary syndrome (PCO-S)
  • Drug-induced
  • Hypothalamic: Exercise amenorrhoea, related to physical exercise, stress amenorrhoea, eating disorders and weight loss (obesity, anorexia nervosa, or bulimia)
  • Pituitary: Sheehan syndrome, hyperprolactinaemia, haemochromatosis
  • Other central regulatory: hypothyroidism, hyperthyroidism, arrhenoblastoma

Read more about this topic:  Amenorrhoea

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