History and exam

Key diagnostic factors

common

decreased libido

Consistent with hypogonadism.

loss of spontaneous morning erections

Suggestive of organic disease, including hypogonadism.

erectile dysfunction

Potentially multifactorial, but hypogonadism should always be considered.

gynaecomastia

Firm ductal tissue that is mainly subareolar. It should be differentiated from adipose tissue in obese patients (often termed lipomastia or pseudogynaecomastia).

Gynaecomastia is more commonly seen in primary hypogonadism.[33]

infertility

A common presenting issue in men with hypogonadism.

uncommon

micropenis

Short penis (often in association with lack of scrotal hyperpigmentation and rugae) is indicative of hypogonadism that occurred before puberty and most probably in utero.

small testes

Very small or shrinking testes (especially <5 mL volume) are indicative of testosterone deficiency.

bifid or hypoplastic scrotum

A manifestation of testosterone deficiency in utero.

cryptorchidism, especially if bilateral

A potential manifestation of testosterone deficiency in utero.

segmental dysproportion

Indicated by an arm span more than 5 cm greater than height, or sitting height <50% standing height.

These proportions develop when hypogonadism occurs before puberty and causes delayed pubertal closure of the epiphyses of the long bones.[7][32]

bitemporal hemianopia

Indicative of a parasellar lesion, which may be causing secondary hypogonadism.

low trauma fractures

Longstanding hypogonadism is associated with osteoporosis that can result in fractures occurring with unusually low levels of trauma.

loss of height

May be indicative of spinal compression fractures associated with low bone mineral density and osteoporosis secondary to hypogonadism.

anosmia

Seen in patients with Kallmann's syndrome.

Other diagnostic factors

common

decreased energy and fatigue

Non-specific finding that may be reported in patients with hypogonadism, may include physical exhaustion and lack of vitality.

uncommon

absent or incomplete puberty

If hypogonadism occurred prior to puberty, patients may report absent or incomplete puberty.

scrotal hypoplasia, hypopigmentation, and absent rugae

Indicative of hypogonadism that started before puberty.

decreased muscle mass and strength

Non-specific. A good tool in research but limited value in clinical practice.

loss of axillary and pubic hair

Specific, but insensitive in hypogonadism.

lack of facial hair

Absence of facial hair and a lower hairline may be noted in many men with congenital hypogonadism.

poor concentration and memory

Non-specific finding that may be reported in patients with hypogonadism.

depressed or labile mood

Non-specific finding that may be reported in patients with hypogonadism.

sleep disturbance

Non-specific finding that may be reported in patients with hypogonadism.

Severe hypogonadism may be associated with hot flushes that may influence sleep quality.

hot flushes and sweats

Hypogonadism may be associated with hot flushes that may influence sleep quality.

tall stature

Some males with congenital hypogonadism may be tall with eunuchoid proportions (i.e., arm span >5 cm greater than height), due to delay in fusion of the epiphyses of the long bones.[7][32]

fine wrinkling of facial skin

May be noted in some patients with prolonged severe hypogonadism.

Risk factors

strong

genetic anomaly

Klinefelter's syndrome is the most common congenital cause of primary hypogonadism.[9][15] Klinefelter's syndrome has a likely population prevalence of >5 per 10,000 men, but only 25% to 50% of men are diagnosed during their lifetime.[9]

Most patients have 47,XXY genotype anomaly; mosaicism is also seen in 6% to 7%.[16] Testosterone secretion may initially be well preserved, but clinically significant hypogonadism invariably presents.

Many genetic mutations may result in congenital hypogonadotrophic hypogonadism (CHH), including Kallmann's syndrome.[2]

type 2 diabetes mellitus

Chronic diseases such as metabolic syndrome and diabetes can lead to secondary hypogonadism.[29]

Secondary (also known as central or hypogonadotrophic) hypogonadism is present in around one third of male patients with type 2 diabetes.[31]

In the European Male Ageing Study (EMAS), age-related accumulation of non-gonadal co-morbidities causing gonadotrophin suppression (e.g., obesity) was a greater risk factor for falling testosterone levels than chronological age.[5][12]

use of alkylating agents, opioids, or glucocorticoids

Can be a cause of both primary and secondary hypogonadism.

Alkylating agents such as cyclophosphamide and chlorambucil can cause primary hypogonadism.[17] Males about to undergo therapy with alkylating agents should be given the option of sperm banking.

High-dose glucocorticoids and opioids reduce gonadal function mainly via direct effects on the hypothalamic-pituitary axis (suppressing gonadotrophin-releasing hormone synthesis).[22]

use of exogenous sex hormones and GnRH analogues

Gonadotrophin-releasing hormone (GnRH) analogues or antagonists (such as those used in prostate cancer treatment), exogenous oestrogens, and exogenous androgens can all cause hypogonadism.[22]

GnRH analogues cause down-regulation of receptors for gonadotrophins, while exogenous sex steroids suppress the hypothalamic-pituitary unit by negative feedback.

hyperprolactinaemia

Elevated prolactin level (from any cause) suppresses kisspeptin-mediated gonadotrophin-releasing hormone secretion.[4]

parasellar tumour or apoplexy of pituitary macroadenoma

Parasellar tumour or apoplexy (haemorrhagic infarction) of pituitary macroadenoma causes compression of gonadotrophs (basophilic cells of the anterior pituitary specialised to secrete luteinising hormone or follicle stimulating hormone), resulting in secondary hypogonadism.

testicular damage

Can occur as a result of trauma, torsion, or irradiation.[9] Also includes orchidectomy for testicular cancers, which are frequently metachronous.

With torsion, the likelihood of damage is increased with duration of unrelieved torsion.

infection

Orchitis related to mumps is the most common infection. HIV is a rare infectious cause.[9] Spermatogenesis is more affected than androgen production.

weak

varicocele

Rarely causes hypogonadism, but does cause increased temperature and/or accumulation of tissue metabolites in the testes.[18]

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