[Hypogonadism in the elderly man. Reliable diagnosis and therapy].

The definition of late-onset-hypogonadism as a hybrid form of primary and secondary hypogonadism corresponds to pathophysiological facts of the age-related decline in gonadal as well as hypothalamic-pituitary functions, eventually manifesting in clinically relevant hypogonadism. To what extent advancing age modulates incidence and nature of hypogonadal symptoms has not been completely investigated. The benefits of testosterone substitution therapy in older men await demonstration in long-term studies and to date, it should be restricted to specialized centers. Currently, serum testosterone levels <12 nmol/l, accompanied by symptoms of androgen deficiency, are regarded as an indication for substitution, provided a prostate carcinoma has been excluded. While late-onset hypogonadism decreases libido, it does not play a direct role in the increasing incidence of erectile dysfunction with advancing age; this symptom is rather associated with vessel-endothelial impairment and may serve as a sentinel symptom for cardiovascular disease. Treatment with phosphodiesterase-5-inhibitors can be regarded as standard; in case of concomitant late-onset hypogonadism, testosterone will have a positive synergistic effect on erectile function.