A 56-year-old man saw his primary care physician because of fatigue, decreased sexual desire, and erectile dysfunction, which had started gradually 2 months prior. He was overweight and had hypertension and hyperlipidemia. Routine laboratory studies showed that his serum testosterone level was very low (10 ng/dL; reference range, 240-950 ng/dL [to convert to nanomoles per liter, multiply by 0.0347]). Topical testosterone gel (2 packets [25 mg] per day) was prescribed. After 8 weeks, his testosterone level increased to 14 ng/dL. During the next 3 months, his physician increased the dose gradually to 6 packs per day; the highest testosterone level at this dosage was 203 ng/dL. He did not notice any relief in his symptoms, and he started to have headaches. Four weeks later, he started to experience bilateral peripheral vision loss. Visual fields examination with the Humphrey Field Analyzer showed temporal hemianopia on the left and superior temporal quadrantanopia on the right. Magnetic resonance imaging (MRI) showed a 15 × 23 × 43-mm sellar mass compressing the optic chiasm. The patient was referred to an endocrinologist.
Akturk HK, Nippoldt TB. Low Testosterone in Men Should Be a Sign Rather Than a Number to IncreaseA Teachable Moment. JAMA Intern Med. Published online October 10, 2016. doi:10.1001/jamainternmed.2016.5761