Background: Hypogonadotropic hypogonadism or secondary hypogonadism is a clinical syndrome that results from gonadal failure due to abnormal pituitary gonadotropin levels. It usually results from absent or inadequate hypothalamic GnRH secretion or failure of pituitary gonadotropin secretion. It may be congenital or acquired. The congenital form has a Normosmic and a Hyposmic/Anosmic variant.
Objective: To highlight an uncommon case of hypogonadotropic hypogonadism in a young Nigerian male.
Case: A 16 year old male Nigerian Senior Secondary School student presented to the endocrinology clinic with complaints of infantile male external genitalia. This was initially noticed by the grandfather who observed that the penis has notincreased in size since birth. However, patient became aware of the symptom at the age of 10 years. He developed axillary and pubic hair at 14 years. The hair was scanty and the frequency of shaving reduced. He also had right sided undescended testis. Nonetheless, there was no associated history of a reduction in the perception of smell, impaired vision, headaches, or hearing loss. No family history of similar illness was reported but patient had a positive family history of diabetes mellitus. Anthropometric measurements showed; height of 164cm, weight of 64kg, body mass index (BMI) of 23.8kg/m², arm span of
168cm, waist circumference of 94cm; crown to pubis length of 75cm, pubis to heel length of 89cm and crown-pubis/pubic-heel ratio of 0.84.
Investigations: Hormone profile showed reduced levels of follicle stimulating hormone (FSH), leutinizing hormone (LH), testosterone and estrogen levels {FSH-0.4 IU/L (1-14IU/L), LH-0.1IU/L (0.7-7.4 IU/L), estrogen-0.1 pg/L(4-94pg/L), testosterone-1 ng/ml (1.8-9.1 ng/ml)} but a normal Prolactin level of 16.0ng/ml (1.8-17.0 ng/ml). Brain Magnetic Rosonance Imaging (MRI) revealed normal brain with age appropriate features and no pituitary mass. Scrotal ultrasound scan (USS) showed Right undescended testis with reduced testicular size(<2cm) and altered echogenicity and echotexture. Abdominopelvic ultrasound scan reported normal findings. The patient had right orchidopexy with favourable outcome. He was placed on IM testosterone 125mg 3 weekly, tablet calcium /VitD3 (600mg/400iu) once daily and regular follow-up visits where treatment would be monitored by a 3-6 monthly testosterone assay, regular assessment of anthropometry and evaluation of secondary sexual characteristics
Conclusion: Hypogonadotropic hypogonadism is a rare disorder. Congenital causes may present with
infantile external genitalia, and treatment is by hormone replacement therapy; which is usually lifelong.