Male hypogonadism is the term used to describe decreased functional activity of the testes with diminished production and action of testosterone. Three different categories of hypogonadism are distinguished depending on the organs or organ systems responsible for the disturbance. These are:
Age-related hypogonadism occupies a special position as it does not readily fit into any of the above categories. Complex aging processes (in the testes and/or the hypothalamic-pituitary system) appear to play a role in the development of age-related testosterone deficiency. This development is often supported by systemic diseases which become more frequent with increasing age (e.g. atherosclerosis).
The clinical picture of hypogonadism depends on whether the androgen deficiency occurs during the fetal period, before puberty or in adulthood.
The differential diagnosis must address the different causes of hypogonadism.