Epidemiology and diagnosis of hypogonadism

Abstract

Testosterone production is dependent on the intact function of the hypothalamic-pituitary-gonadal axis. Primary hypogonadism stems from testicular dysfunction and can arise from injury or chromosomal/genetic causes. Hypothalamic and/or pituitary failure cause secondary hypogonadism, most often as a result of chromosomal or genetic defects. Late-onset hypogonadism describes abnormally low testosterone in fully developed males. In the absence of a speci fi c pathology, this is most likely caused by a combination of central and peripheral dysfunction. Late-onset hypogonadism is strongly associated with advanced age and components of the metabolic syndrome. Signs and symptoms of hypogonadism depend on the age of onset. Testosterone de fi ciency in utero can cause congenital malformations of the reproductive tract, which in the most severe cases can result in a female phenotype. Hypogonadism in adolescence can result in failure to undergo a normal pubertal development, including disturbances in the development of male secondary sexual characteristics. Lateonset hypogonadism produces symptoms, including reduced libido, erectile dysfunction, and decreased energy levels and decreased vitality. The diagnosis of hypogonadism relies on a combination of patient history, physical examination, and laboratory values.