Aetiology

Abstract

Abstract Male hypogonadism is diagnosed in patients who have symptoms and signs of androgen deficiency, and repeatedly low serum testosterone concentrations and decreased sperm production. The aetiology of hypogonadism may be due to disorders of the testes (primary hypogonadism) or hypothalamus or pituitary gland (secondary hypogonadism), or combined disorders. Primary and secondary hypogonadism are distinguished by gonadotropin, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) concentrations. Either primary or secondary hypogonadism may be caused by a structural or congenital disorder of the hypothalamic–pituitary–testicular (HPT) axis that is usually permanent and necessitates testosterone treatment (organic hypogonadism) or a disorder that results in suppressed function of an intact HPT axis that is potentially reversible with treatment of the etiologic condition or discontinuing the offending medication (functional hypogonadism). The benefits and risks of testosterone treatment in men who have functional hypogonadism have not been evaluated fully in randomized, double-blind, placebo-controlled trials, while managing the underlying conditions may reverse the hypogonadism and confer other health benefits. Given that clinical management of primary and secondary hypogonadism due to organic or functional aetiologies vary, it is important to evaluate and establish the aetiology of hypogonadism prior to initiating testosterone treatment.