- Hypogonadism pre-puberty:
- o p/c: gynecomastia, high pitched voice, testicular volume <5ml, penile length <5cm, arm span 6cm or more than height, delayed bone age, reduced muscle bulk, absent pubic hair, absent erections, absent libido.
- If onset is post-puberty:
- o p/c: normal body proportions, facial wrinkling, gynecomastia, pigmented scrotum, osteoporosis, testicular volume >15ml, penile length >5cm, reduced muscle bulk, reduced pubic hair, reduced erections, reduced libido.
- o Acquired hypogonadism affects 20% of all men
- Primary hypogonadism = testicular failure:
- o Main causes are systemic disease, renal failure, and alcoholic liver cirrhosis.
- o Adult men with mumps – 25% develop orchitis and half of these develop to late gonadal failure (primary)
- o Viral causes are not uncommon
- o Testicular trauma, torsion, gonadal RT or systemic CT drugs
- Specific genetic diseases:
- o Kleinfelter’s syndrome (XXY):1/1000, small testes, gynecomastia, eunuch-like appearance from testosterone deficiency, azoospermia, and infertility.
- Secondary hypogonadism = hypothalamic-pituitary failure:
- o Caused by severe illness, malnutrition, pituitary disease, hyperprolactinaemia.
- o Kallman’s syndrome: a genetic X-linked syndrome, autosomal dominant or recessive, M>F (4>1), 1/10,000, causes isolated failure of hypothalmic gonadotrophin-releasing hormone (GnRH) release with anosmia. MRI shows absent olfactory bulbs.
- Mx of male hypogonadism:
- o Androgen replacement therapy – will relieve symptoms and prevent osteoporosis – but will not improve fertility (which is irreversible in primary failure).
- o Gonadotrophins can be used to induce fertility in secondary hypogonadism.