Hypogonadism (male) Flashcards
Define hypogonadism (male)
Syndrome of decreased testosterone production, sperm production, or both
Aetiology of primary hypogonadism (male)
3
Gonadal dysgenesis - e.g. Klinefelter’s syndrome, undescended testicles
Gonadal damage - e.g. infection, torsion, trauma, autoimmune, iatrogenic
Rare causes - e.g. defects in enzymes involved in testoterone synthesis
Aetiology of secondary hypogonadism (male)
7
Pituitary/hypothalamic lesions Hyperprolactinaemia GnRH deficiency - Kallmann’s syndrome Systemic/chronic disease Rare causes - genetic mutations Prader-Willi syndrome Laurence-Moon-Biel syndrome
Epidemiology of hypogonadism (male)
infertility, most common cause of 1º
Primary hypogonadism accounts for 30-40% of male infertility & secondary accounts for 1-2%
Klinefelter’s syndrome (XXY) most common cause of primary hypogonadism
Presenting symptoms of hypogonadism (male)
5
Delayed puberty Decreased libido Impotence Infertility Symptoms of underlying cause
Features of Klinefelter’s syndrome
6
intellectual dysfunction behavioural abnormalities tall poor muscle tone gynaecomastia small testes/infertility
Signs of hypogonadism (male) on physical examination
3 groups
General
Pre-pubertal hypogonadism
Post-pubertal hypogonadism
Signs of hypogonadism (male) on physical examination - general
Measure testicular volume using Prader’s orchidometer
Normal adult volume = 15-25ml
Signs of hypogonadism (male) on physical examination - pre pubertal
(4)
Signs of delayed puberty
Gynaecomastia
Eunuchoid proportions (arm span>height)
Features of underlying cause (e.g. undescended testicle, anosmia in Kallmann’s syndrome)
Signs of hypogonadism (male) on physical examination - post pubertal
(5)
Decreased pubic/axillary/facial hair Soft & small eyes Gynaecomastia Fine perioral wrinkles Features of underlying cause (e.g. visual defects if pituitary)
Signs of delayed puberty
4
high pitched voice
decreased pubic/axillary/facial hair
small or undescended testicles
small penis
Investigations for hypogonadism (male)
3 groups
General
Primary hypogonadism
Secondary hypogonadism
Investigations for hypogonadism (male) - general
5
Serum total testoterone Sex hormone binding globulin (SHBG) Albumin LH & FSH Assess bone age (risk of fracture)
Investigations for primary hypogonadism (male)
3
Low testoterone
High LH & FSH
Can be investigated using karyotyping - Klinefelter’s
Investigations for secondary hypogonadism (male)
7
Low testoterone
Inappropriately normal/low LH & FSH
Pituitary function tests MRI of hypothalamic/pituitary area Visual field testing Smell testing (for anosmia) Iron testing (for hereditary haemochromatosis)
