Hypogonadism

 

• Definition and causes

  Impaired function of the gonads (ovaries or testes), leading to reduced sex hormone levels.

  Primary hypogonadism

  Klinefelter's syndrome:

  • 47 XXY.
  • 1/500 boys.
  • 75% undiagnosed.
  • Clinical features: tall, hypogonadism (small testes, gynaecomastia, infertility), learning/behavioural problems.

  Turner's syndrome:

  • 45 X.
  • 1/3000 girls.
  • Characteristic appearance: short stature, webbed-neck, broad chest, wide carrying angle (cubitus valgus), low-set ears.
  • Other features: underdeveloped 'streak' ovaries, horseshoe kidney, lymphoedema, aortic coarctation and dissection.

  Cryptorchidism:

  • Undescended testes.
  • Can be standalone or part of a condition such as Noonan's or Klinefelter's.

  Acquired primary hypogonadism:

  • Orchitis
  • Testicular trauma/radiation
  • Chronic liver disease, especially if due to alcohol.
  • Drugs: anabolic steroids, alkylating agents.

  Secondary hypogonadism

  • Hyperprolactinaemia
  • Hypopituitarism
  • Isolated hypogonadotrophic hypogonadism (IHH): hypothalamic GnRH failure. 50% are due to Kallmann syndrome, in which it is accompanied by anosmia.
  • PCOS

• Signs and symptoms

  General:

  • Sexual: sub-fertility, ↓libido, small gonads.
  • Psychological: depression, fatigue.
  • Connective tissue: ↓bone density, hair loss.
  • If congenital or onset is pre-pubertal → failed/incomplete puberty → ↓growth and no secondary sex features.

  In females:

  • Amenorrhea
  • Vaginal dryness.
  • Acne
  • Hirsutism
  • Small breasts.

  In males:

  • Erectile dysfunction.
  • ↓Sperm count.
  • Gynecomastia, due to raised estrogen/testosterone ratio.
  • Small penis if pre-pubertal onset.

  Signs and symptoms of cause e.g. ↑PRL, hypopituitarism.

• Investigations

  • Men: 2 morning serum testosterone samples.
  • Women: serum estradiol (E2).
  • Serum gonadotrophins (LH/FSH).

• Management

  Replace hormones – testosterone or estrogen – if there is clinical and laboratory evidence of deficiency.