II. Causes

  1. Primary (Testicular) Hypogonadism (High LH, FSH)
    1. Male Menopause (Normal Physiologic change with age)
      1. Especially over age 70 years
    2. Klinefelter's Syndrome
    3. 5-alpha reductase deficiency
    4. Myotonic dystrophy
    5. Orchiectomy
    6. Cryptorchidism
    7. Hemochromatosis
    8. Bilateral mumps Orchitis
    9. Toxic damage
      1. Alcohol
      2. Heavy metals (e.g. Hemochromatosis)
      3. Chemotherapy
    10. HIV Infection or AIDS
  2. Secondary (Central) Hypogonadism (Low LH, FSH)
    1. Pituitary Adenoma or Prolactinoma
    2. Kallmann Syndrome
    3. Fertile Eunuch Syndrome
    4. Craniopharingioma
    5. Pituitary surgery
    6. Intracranial radiation

III. Symptoms

  1. Sexual Dysfunction
    1. Decreased libido (erectile function often intact)
    2. Decreased sexual activity
  2. Decreased facial and body hair
  3. Decreased Muscle Strength and decreased muscle mass
  4. Fatigue and lethargy
  5. Depressed mood
  6. Mild Cognitive Impairment
  7. Increased visceral fat

IV. Signs

  1. Prepubertal Onset
    1. Hypoplastic penis and Testes
    2. Thin, smooth skin
    3. Voice does not deepen
    4. Female distribution of pubic hair
    5. Absence of beard
    6. Poor muscle development
    7. Long limbs
    8. Broad hips
    9. Gynecomastia
  2. Postpubertal Onset
    1. Testicular atrophy and pallor
    2. Reduced body hair
    3. Increased visceral fat
    4. Decreased muscle mass

V. Radiology

  1. Prepubertal delay in epiphyseal closure

VI. Labs: Secondary effects of Hypogonadism

VII. Diagnosis

  1. Serum Androgens
    1. Testosterone
      1. Decreased in all cases
    2. Leutinizing Hormone (LH)
      1. Primary Testicular Failure: High LH
      2. Central failure: Low LH
    3. Follicle Stimulating Hormone (FSH)
      1. High level suggests irreversible Hypogonadism
    4. GnRH
  2. Secondary cause
    1. Urine 17-Ketosteroids

VIII. Diagnosis

  1. Eliminate other cause
    1. Urine 17-Ketosteroids normal
  2. Primary Hypogonadism (Testicular)
    1. Leutinizing Hormone (LH) elevated
    2. Follicle Stimulating Hormone (FSH) elevated
    3. Testosterone is low
  3. Secondary Hypogonadism (Central)
    1. Leutinizing Hormone (LH) decreased
    2. Follicle Stimulating Hormone (FSH) decreased
    3. GnRH may be decreased
    4. Testosterone level decreased

IX. Management

X. Complications of untreated Hypogonadism

  1. Osteoporosis
  2. Diminished Muscle Strength and other androgen effects

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