ABSTRACT
Adult onset hypogonadism, also referred to as late-onset hypogonadism is a condition characterised by biochemically low levels of testosterone in the presence of clinical symptoms and signs of testosterone deficiency. Adult onset hypogonadism can be due to a primary disorder of the testis which is unable to produce sufficient levels of testosterone or secondary to a disorder of the hypothalamus or pituitary gland which results in decreased stimulation of the testis to produce testosterone. Pulsatile Gonadotropin releasing hormone (GnRH) from the hypothalamus stimulates release of luteinising hormone (LH) and follicle stimulating hormone (FSH) from the anterior pituitary gland. A large population-based study demonstrated that 76.7% had a normal testosterone level. The diagnosis of adult onset hypogonadism is made in the presence of signs and symptoms and confirmed low serum testosterone levels. Past medical history should cover risk factors for primary hypogonadism such as testicular trauma, orchitis, chemotherapy or radiotherapy and a history of undescended testis.
