Endocrine Abstracts

Case: A 21 year old gentleman presented to endocrine clinic with failure to develop secondary sexual characteristics. He had no growth since age 16, nor any change in voice, body hair or muscle or genital growth. Examination was in keeping with pubertal staging Tanner stage II. His right testicular volume was 5ml and left testicular volume 4ml. He had normal sense of smell. Investigations demonstrated low testosterone at 1.6 nmol/l (10-30). Results showed hypogonadotropic hypogonadism with inappropriately normal LH at 0.9 U/l (0.6-9) and FSH at 1.2 U/l (1-10). His remaining pituitary hormones were normal. His diagnosis was thought to be either Kallman syndrome with normosmia or congenital hypogonadotropic hypogonadism. He was commenced on testosterone replacement. For a period of time he was also using additional testosterone replacement purchased at his gym, but this was stopped following advice in clinic. His repeat testosterone was normal and his symptoms improved, with improved energy levels, increasing muscle bulk and facial and pubic hair, and deepening voice. He continued on testosterone replacement and progressed though pubertal stages. Following this his partner became pregnant. His testicular volume was reassessed and right volume was 20 ml, with left being 12 ml. His repeat gonadotrophins showed normal testosterone level with detectable FSH and LH. He underwent a semen analysis and had a low but detectable sperm count. Following this his testosterone treatment was stopped. Following cessation of testosterone replacement his testosterone level remains normal (12.2 nmol/l), and he has normal sexual characteristics, erectile function and libido.

Discussion: This demonstrates a case of reversible congenital hypogonadotropic hypogonadism, with recovery of fertility following treatment, and recovery of reproductive axis following cessation of testosterone replacement. This raises the question of whether trialling withdrawal of treatment with monitoring of results would be beneficial in a subgroup of patients.