Hypogonadism: Its Prevalence and Diagnosis.

Hypogonadism is a clinical syndrome, which results from the failure of the testes to produce physiologic levels of testosterone and a normal number of spermatozoa due to defects at one or more levels of the hypothalamic-pituitary-gonadal axis. Primary hypogonadism results from malfunction at the level of the testes due to a genetic cause, injury, inflammation, or infection. Hypothalamic and/or pituitary failure leads to secondary hypogonadism, most often as a result of genetic defects, neoplasm, or infiltrative disorders. The signs and symptoms of hypogonadism depend on the age of onset, severity of androgen deficiency, and underlying cause of androgen deficiency.