Endocrine Abstracts

Background: Hypogonadism is common among human immunodeficiency virus (HIV)-infected men. The actual prevalence remains poorly defined and ranges from less than 10% to over 50% in different studies. Secondary hypogonadism is the most common cause of hypogonadism among HIV-infected men. In hypogonadal HIV-infected men, naive of highly active antiretroviral therapy (HAART), around 75% have secondary hypogonadism due to the suppression of gonadotropins by the active inflammation and disease. Hematologic neoplasias, occurring in 1.6% of Klinefelter patients could develop in the pituitary region. Gonadal and extragonadal germ cell tumours (mediastinal germ cell tumours, teratoma, teratocarcinoma, choriocarcinoma) may occur.

Case presentation: We followed a thirty-five-year-old male patient diagnosed in our Endocrine outpatient department with Klinefelter Syndrome for appropriate replacement therapy with intramuscular testosterone. Nine months following his diagnosis of hypergonadotropic hypogonadism, endocrine laboratory testing revealed suppressed gonadotrophins despite lengthening of periods in testosterone administration. The patient was well-nourished and asymptomatic for a pituitary tumour. The patient reported no opioids abuse or steroids. Serum levels of free testosterone and SHBG were in the normal range when we tested it after 14 weeks from the last administration of testosterone. We excluded the reversible causes of hypogonadotropic hypogonadism. Serum prolactin was in the normal range. Ultrasound of the testis and normal values for HCG, AFP and LDH excluded a germinal tumour. Blood tests were positive for HIV infection with normal CD4 count. The patient started HAART with Triumeq (dolutegravir 50 mg/abacavir 600 mg/lamivudine 300 mg). Restauration of normal gonadotrophins secretion after ART initiation will explain the HIV-related cause of hypogonadotropic hypogonadism in this patient.

Conclusion: We report the occurrence of the secondary hypogonadism in a Klinefelter patient under testosterone replacement that drove specific tests that revealed an early stage of HIV infection without advanced degrees of immunosuppression (CD4 > 100 cells/mm³). Undernutrition, severe illness, drugs, pituitary dysfunction, were excluded in our patient. The endocrinologists frequently overlook HIV infection as a cause of hypogonadotropic hypogonadism. Yet, it must be considered between causes of unexplained gonadotrophins suppression in these patients.