Male Hypogonadism

Male hypogonadism is defined as the underproduction of sperm or testosterone, or both, by the testes (also called testicles). Starting at puberty, the pituitary gland releases hormones that stimulate the testicles to produce testosterone, the hormone responsible for male physical characteristics. In the testicles, testosterone also stimulates the production of sperm.

Diagnosis of male hypogonadism begins with a medical history and physical examination. There are many possible symptoms and signs that suggest low testosterone, or androgen deficiency, in adult men:

• Incomplete sexual development
• Reduced sexual desire (libido) and activity
• Decreased spontaneous (night-time and morning) erections
• Breast discomfort or enlargement
• Loss of body hair, reduced shaving
• Very small or shrinking testes
• Inability to father children, low or zero sperm counts
• Height loss, low bone mineral density
• Reduced muscle bulk and strength
• Hot flushes, sweats
• Decreased energy
• Fatigue
• Mild depression

Blood tests are used to determine whether testosterone levels are in the normal range. This is generally 300 to 1,000 ng/dL (10.4 to 34.7 nmol/L), but the normal range may differ depending on the laboratory that conducts the test. To diagnose low testosterone, a man may need to have more than one early-morning blood test and, sometimes, other tests of the pituitary gland.

Causes of male hypogonadism
Male hypogonadism can be primary (resulting from a problem with the testes) or secondary (resulting from a problem with the pituitary gland or hypothalamus and their release of luteinizing hormone and follicle stimulating hormone) or a mix. With primary hypogonadism, sperm count and testosterone are low, but LH and FSH are high. With secondary hypogonadism, sperm count and testosterone are low, and LH and FSH levels are normal or low.

Speaking more generally, low testosterone can be caused by:

• testicular injury (trauma, castration, radiation, or chemotherapy) or infection
• hormonal disorders, such as pituitary tumors or diseases, or high levels of prolactin (a hormone produced by the pituitary that affects testosterone levels)
• other chronic medical diseases such as HIV/AIDS; type 2 diabetes; and obesity, liver, or kidney disease
• some medications such as opiate pain medications
• genetic conditions including Klinefelter syndrome, Kallmann syndrome, and Prader-Willi syndrome

Many older men have low testosterone levels and, in many cases, the cause isn’t known.

Treatment of male hypogonadism/androgen deficiency
Treatment with testosterone replacement therapy is recommended for men with low testosterone levels and symptoms or signs of androgen deficiency. Men with one of the following should not be treated:

• Breast or prostate cancer
• A lump or hardness in the prostate or high PSA (prostate specific antigen) level, which suggests  prostate cancer or other prostate problems
• A high number of red blood cells, untreated obstructive sleep apnea (long pauses in breathing during sleep), severe untreated enlargement of the prostate, or severe heart failure

The overall goal of testosterone hormone therapy is to increase testosterone levels from the low to the middle of the normal range. Depending on the reason for treatment, goals may vary from patient to patient but should include improving or maintaining the signs of masculinity (such as deep voice, growth of beard, pubic hair), and improving sex drive, erections, mood and energy, muscle bulk and strength, and bone strength.

There are several ways to replace testosterone:

• Injections (usually every 2 weeks)
• Patches (put on skin once a day)
• Gel preparations (put on skin once a day)
• Buccal tablets (applied to the gums twice a day)
• Pellets (implanted under the skin)
• Pills (available in some countries outside the United States)

The way testosterone is given will depend on the patient’s preference and tolerance, and cost. There are possible downsides of the various types of testosterone therapy. Injections into the muscle may be uncomfortable and linked to ups and downs in symptoms; patches may cause skin redness and rashes; gels may transfer testosterone to others who come into contact with the patient’s skin where the medication is applied; and buccal tablets may cause gum irritation.

It is not known whether long-term testosterone treatment increases the likelihood of prostate cancer.  However, men who have a higher risk of developing prostate cancer, such as African American men and men older than age 45 who have close relatives with prostate cancer, and all men over age 50 should be monitored for prostate cancer during testosterone treatment.