Hypogonadism

When hypogonadism develops before the age of puberty, the manifestations are those of impaired puberty:

• Small testes, phallus, and prostate
• Scant pubic and axillary hair
• Disproportionately long arms and legs (from delayed
• epiphyseal closure)
• Reduced male musculature
• Gynecomastia
• Persistently high-pitched voice

Postpubertal loss of testicular function results in slowly evolving subtle clinical symptoms and signs. In aging men, these symptoms and signs may be difficult to appreciate because they are often attributed to “getting older.” The growth of body hair usually slows, but the voice and the size of the phallus usually remain unchanged. Prostate size may decrease in hypogonadal men, but the amount of change is related to the severity of testosterone deficiency. Typical temporal hair recession and balding usually do not occur, and if they did, these manifestations would not be expected to prompt a patient to seek medical attention. Patients with hypogonadism may have the following findings:

• Progressive decrease in muscle mass
• Loss of libido
• Impotence
• Oligospermia or azoospermia
• Occasionally, menopausal-type hot flushes (with acute onset of hypogonadism)
• Poor ability to concentrate

The major objectives of the initial assessment of a patient with possible hypogonadism are to distinguish primary gonadal failure (hypergonadotropic hypogonadism with low testosterone and increased FSH and LH levels) from hypothalamic-pituitary disorders (hypogonadotropic hypogonadism with low testosterone and low to normal FSH and LH levels) and to make a specific diagnosis.

• Men with hypogonadotropic disorders may achieve fertility with gonadal stimulation.

• Men with hypergonadotropic disorders are treated with testosterone to achieve virilization and are usually, but not invariably, incapable of achieving fertility.

Investigation:

• Level of testosterone determination is the threshold test in the evaluation of suspected male hypogonadism.

• If the clinical findings indicate that hypogonadism is present and the total testosterone levels are normal or borderline low, the level of SHBG or free testosterone should be determined.

• Gonadotrophins ( FSH and LH ) is used to determine whether the hypogonadism is related to a primary testicular disorder or to pituitary disease. FSH has a longer half-life than does LH and is more likely to provide adequate results on a single blood sample.

• GnRH Stimulation Test

• In men with acquired hypogonadotropic hypogonadism, who usually have a reduced libido and impotence, a prolactin level should be determined to evaluate for the presence of a prolactinoma or other cause of hyperprolactinemia. High prolactin levels can reduce GnRH and testosterone levels.

• Pituitary Imaging

• Bone Mineral densitometry