A 25-year-old man is found to have small testes on physical examination. He has normal male pattern facial and pubic hair. Further laboratory testing reveals a decreased sperm count and normal serum testosterone level. Which of the following is the most likely cause of these findings?

Question

A 25-year-old man is found to have small testes on physical examination.  He has normal male pattern facial and pubic hair.  Further laboratory testing reveals a decreased sperm count and normal serum testosterone level.  Which of the following is the most likely cause of these findings?

Quizplus · Accepted Answer

This patient is taking exogenous anabolic steroids (eg, testosterone, synthetic steroidal androgens). Anabolic steroids are utilized by athletes in an effort to increase lean body mass. Adverse effects associated with the excessive use of anabolic steroids include acne, gynecomastia, azoospermia, decreased testicular size and increased aggression. Hypertension, dyslipidemia, cholestatic hepatitis and hepatic failure may also occur. Serum testosterone levels can be low in individuals taking only synthetic androgens (eg, trenbolone), but are often within the normal range or elevated due to exogenous testosterone intake. Although serum testosterone may appear adequate, lower than normal local testosterone levels in the seminiferous tubules lead to decreased spermatogenesis. (Choice A) Kallmann syndrome is a cause of GnRH deficiency, which results in abnormally low production of sex hormones by the gonads. Affected males present with delayed puberty and an abnormally small penis in addition to other nonsexual findings such as anosmia, hearing loss, and cleft palate. (Choice B) 5-alpha reductase deficiency results in an inability to convert testosterone to dihydrotestosterone in the peripheral tissues. Affected males are born with ambiguous genitalia. Following puberty, affected patients have normal or elevated levels of serum testosterone. (Choice C) Klinefelter syndrome (XXY seminiferous tubule dysgenesis) is a common cause of male hypogonadism. Small, firm testes and a decreased serum testosterone level are characteristic. Patients may exhibit diminished secondary sexual characteristics. (Choice E) Hyperprolactinemia causes hypogonadotropic hypogonadism by suppressing LH and FSH release thereby decreasing serum testosterone in affected males. Symptoms include diminished libido, impotence and oligospermia. Educational objective: Adverse effects associated with the use of excessive doses of anabolic steroids include acne, gynecomastia, azoospermia, decreased testicular size, and increased aggression. When measured, serum testosterone is typically normal or elevated. However, endogenous testosterone production and spermatogenesis are decreased.

A 25-Year-Old Man Is Found to Have Small Testes on Physical