Hypogonadism-male Flashcards
Define:
A syndrome of decreased testosterone and/or sperm production
Aetiology/risk factors of primary hypogonadism:
o Gonadal dysgenesis (e.g. Klinefelter’s syndrome, undescended testicles)
o Gonadal damage (e.g. infection, torsion, trauma, autoimmune, iatrogenic)
o Rare causes (e.g. defects in enzymes involved in testosterone synthesis)
o Post orchitis: mumps, HIV, brucellosis, leprosy
o Renal failure, liver cirrhosis or alcohol excess (toxic to Leydig cells)
Aetiology/risk factors of secondary hypogonadism:
o Pituitary/Hypothalamic lesions
o GnRH deficiency (Kallmann’s syndrome)
o Hyperprolactinaemia
o Systemic/chronic diseases e.g. COPD, HIV, DM
o Rare causes: genetic mutations
o Prader-Willi syndrome (short, small hands, almond-shaped eyes, learning difficulty, postnatal hypotonia)
o Laurence-Moon-Biedl syndrome (obesity, polydactyly, retinitis pigmentosa, learning difficulty)
o Age
Epidemiology:
Primary is the cause 30-40% male infertility
Secondary - 1-2% of cases
Symptoms:
Delayed puberty
Decreased libido
Impotence
Infertility
Signs of Klinefelter’s - intellectual dysfunction , behavioural abnormalities, poor muscle bulk, tall stature and small testes.
Signs pre-pubertal:
o Signs of delayed puberty • High pitched voice • Decreased pubic/axillary/facial hair • Small or undescended testicles • Small penis o Gynaecomastia o Eunuchoid proportions (arm span > height) o Features of underlying cause (e.g. undescended testicle, anosmia in Kallmann's syndrome)
Signs post-pubertal:
o Decreased pubic/axillary/facial hair o Soft and small eyes o Gynaecomastia o Fine perioral wrinkles o Features of underlying cause (e.g. visual defects if pituitary cause)
Investigations:
• Serum total testosterone • Sex hormone binding globulin (SHBG) • Albumin • LH and FSH • Primary Hypogonadism: o Low testosterone o High LH and FSH • Secondary Hypogonadism: o Low testosterone o Inappropriately normal/low LH and FSH • Primary - can be investigated using karyotyping (check for Klinefelter's syndrome) • Secondary o Pituitary function tests o MRI of the hypothalamic/pituitary area o Visual field testing o Smell testing (for anosmia) o Iron testing (for hereditary haemochromatosis) • Assess bone age (risk of fracture)