Hypogonadism, Male

Key Features

Essentials of Diagnosis

• Diminished libido and erections

• Fatigue, depression, reduced exercise endurance

• Decreased growth of body hair

• Small or normal testes; low serum total testosterone or free testosterone level

• Luteinizing hormone (LH) and follicle-stimulating hormone (FSH)

  • Low or normal in hypogonadotropic hypogonadism (insufficient gonadotropin secretion by pituitary)

  • Increased in testicular failure (hypergonadotropic hypogonadism)

General Considerations

• Caused by deficient testosterone secretion by the testes

• In hypogonadotropic form, FSH and LH deficiency may be isolated or accompanied by other pituitary hormone abnormalities

Hypogonadotropic hypogonadism (Low testosterone with normal or low LH)

• Causes (Table 26–12) can be primary (failure to enter puberty by age 14) or acquired

• Causes of acquired hypogonadotropic hypogonadism include

  • Pituitary or hypothalamic tumors

  • Granulomatous diseases

  • Lymphocytic hypophysitis

  • Cushing syndrome

  • Adrenal insufficiency

  • Thyroid hormone excess or deficiency

  • Hemochromatosis

  • Estrogen-secreting tumor (testicular, adrenal)

  • Chronic illness or malnourishment

  • Kallmann syndrome

  • Idiopathic or associated with normal aging or obesity

Hypergonadotropic hypogonadism (Testicular Failure with high LH)

• Causes (Table 26–12)

  • Male climacteric (andropause)

  • Klinefelter syndrome: at least one Y chromosome and at least two X chromosomes (47,XXY et al)

  • Orchitis, eg, mumps, gonorrhea, tuberculosis, leprosy

  • Testicular failure secondary to radiation therapy or chemotherapy

  • Autoimmune, uremia, testicular trauma or torsion, lymphoma, myotonic dystrophy, androgen insensitivity

Clinical Findings

Symptoms and Signs

• Delayed puberty if congenital or acquired during childhood

• Decreased libido with acquired hypogonadism in most

• Erectile dysfunction, hot sweats, fatigue, or depression

• Infertility, gynecomastia, headache (if pituitary tumor)

• Decreased body, axillary, beard, or pubic hair but only after years of severe hypogonadism

• Loss of muscle mass and weight gain due to increased subcutaneous fat

• Testicular size, as assessed with orchidometer, may decrease but usually remains normal in length (> 6 cm) in postpubertal hypogonadotropic hypogonadism

• In Klinefelter syndrome, manifestations are variable

  • Generally, testes normal in childhood, but usually become small, firm, fibrotic, and nontender in adolescence

  • Normal onset of puberty, ...