In secondary hypogonadism, the testicles are normal but function improperly due to lack of stimulation by the pituitary hormones.
The complications of untreated hypogonadism differ depending on the age of onset. If hypogonadism occurs during fetal development, a baby may be born with ambiguous genitalia. If hypogonadism develops before puberty, a lack of body hair and impaired penis and testicle growth may occur. Infertility, erectile dysfunction, decreased sex drive, fatigue, muscle loss or weakness, enlarged male breasts, decreased beard and body hair growth, and osteoporosis are possible complications of hypogonadism.
Causes
Kallmann's syndrome Defective development of the hypothalamus — the area of the brain that controls the secretion of pituitary hormones — can cause hypogonadism. Impaired release of hormones by the hypothalamus causes inadequate secretion of pituitary and testicular hormones, resulting in testosterone deficiency.
This abnormality is also associated with impaired development of the olfactory nerves at the front of the brain, causing the inability to smell (anosmia). Other associated conditions include poor color vision and cleft palate.
Pituitary disorders An abnormality in the pituitary gland can impair the release of hormones from the pituitary gland to the testicles, affecting normal testosterone production. Head trauma resulting in pituitary dysfunction may be a cause. A pituitary tumor or other types of brain tumors located near the pituitary gland may cause testosterone or other hormone deficiencies.
Inflammatory disease Certain inflammatory diseases such as sarcoidosis involving the pituitary gland can affect testosterone production and cause hypogonadism.
Medications The use of certain drugs can affect testosterone production. Some psychiatric drugs and medications taken for heartburn or gastroesophageal reflux disease (GERD) may cause hypogonadism.
In secondary hypogonadism, the testicles are normal but function improperly due to lack of stimulation by the pituitary hormones.
