Underactivity of the testes, resulting in low levels of the sex hormone testosterone and impaired production of sperm
- Sometimes caused by a chromosomal abnormality
- Alcohol abuse is a risk factor
- Age is not a significant factor
Reduced activity of the testes, known as hypogonadism, results in the under-production of the male sex hormone testosterone and impaired sperm production. In boys who have not reached puberty, testicular growth and the development of secondary sexual characteristics (such as growth of facial, armpit, and pubic hair, muscle growth, and deepening of the voice) may be delayed or arrested. Hypogonadism is uncommon.
Abnormal development of the testes due to a chromosome disorder, such as Klinefelter’s syndrome, may cause hypogonadism, as may failure of the pituitary gland to produce sufficient hormones, which may be the result of a pituitary tumour. There are also a number of disorders that may cause damage to the testes and lead to hypogonadism, such as torsion of the testis and mumps. Excessive consumption of alcohol, chemotherapy, and radiotherapy can also cause hypogonadism.
What are the symptoms?
If hypogonadism occurs after puberty, the only effect may be infertility (see Male infertility) due to the reduced production of sperm. However, some of the following symptoms may also be evident:
Reduction in the size of the genitals.
Lowered sex drive.
Reduced growth of facial, underarm, and pubic hair.
Reduced muscle strength.
When hypogonadism develops before adolescence, it may result in late onset of puberty (see Abnormal puberty in males).
What might be done?
The doctor will carry out a physical examination to determine whether the genitals and secondary sexual characteristics have developed normally. A blood test may be done to measure the levels of testosterone and other hormones and to look for a chromosomal abnormality.
Treatment is aimed at the underlying cause. For example, synthetic male hormones (see Sex hormones and related drugs) may be used to treat disorders of the testes. If underactivity of the pituitary gland is the cause, pituitary hormones may be given (see Pituitary drugs). A pituitary tumour may be removed surgically. In boys, hormone treatment stimulates puberty, including growth and sexual development; in men, it encourages growth of facial hair, muscle strength, potency, and sex drive. Side effects of treatment with hormones may include temporary breast development (see Gynaecomastia) and acne.
If the genitals are normal, treatment may improve sexual potency and fertility; if hypogonadism is due to a testicular disorder, fertility is rarely achieved.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.