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Testosterone Deficiency

Testosterone Deficiency is a topic covered in the 5-Minute Clinical Consult.

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Basics

Description

  • Testosterone (T) is a critical anabolic hormone.
  • It is the principle circulating androgen in males.
  • Critical in cardiovascular, reproductive, and metabolic systems
  • Testosterone deficiency (TD) is characterized by low levels of T in addition with signs and symptoms.
  • No universally accepted threshold of T concentration to distinguish eugonadal from hypogonadal men, but the FDA definition is T <300 ng/dL.
  • T levels can be affected by disruptions to the hypothalamic–pituitary–testis axis, age, and medical comorbidities.
  • T levels correlate with overall health and may be associated with sexual dysfunction.
  • Special consideration is needed for men with low T who desires future fertility.
  • Synonym(s): hypogonadism; hypoandrogenism; androgen deficiency; and low T

Epidemiology

Incidence
  • Overall incidence increases with age.
  • 481,000 new cases in United States ages 40 to 69 years

Prevalence
  • Estimates of TD vary, typically 20% of men >60 years, 30% >70 years, and 50% >80 years of age.
  • Symptomatic TD in United States ages 40 to 69 years is 6–12.3%.
  • 2.4 million men in United States ages 40 to 69 years

Etiology and Pathophysiology

  • Normal hypothalamic–pituitary–testis axis:
    • Hypothalamus produces GnRH, which stimulates pituitary to produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
    • LH stimulates Leydig cells to produce T.
    • T inhibits LH/GnRH through negative feedback.
  • Primary hypogonadism: Testes produces insufficient amount of T; FSH/LH levels are elevated.
  • Secondary hypogonadism: low T from inadequate production of LH
  • Congenital syndromes: cryptorchidism, Klinefelter, hypogonadotropic hypogonadism (Kallmann)
  • Acquired: cancer, trauma, orchiectomy, steroids
  • Infectious: mumps orchitis, HIV, tuberculosis
  • Systemic: Cushing, hemochromatosis, autoimmune, severe illness (e.g., renal and liver disease), metabolic syndrome, obesity, obstructive sleep apnea
  • Medications and drugs: LHRH agonists, corticosteroids, ethanol, marijuana, opioids, SSRIs
  • Elevated prolactin: prolactinoma, dopamine antagonists (neuroleptics and metoclopramide)

Genetics
  • Usually normal
  • Klinefelter: XXY karyotype
  • Kallmann syndrome: abnormal GnRH secretion due to abnormal hypothalamic development

Risk Factors

  • Obesity, diabetes, COPD, depression, thyroid disorders, malnutrition, alcohol, stress
  • Chronic infections, inflammatory states, narcotic use
  • Medications that affect T production or metabolism
  • Undescended testicles, varicocele
  • Trauma, cancer, testicular radiation, chemotherapy, disorders of the pituitary and/or hypothalamus

General Prevention

General health maintenance and treatment of obesity

Commonly Associated Conditions

  • Infertility, erectile dysfunction, low libido
  • Poorer health outcomes
  • Osteopenia/osteoporosis
  • Diabetes, insulin resistance, metabolic syndrome
  • Increased body weight, adiposity
  • Depressed mood, poor concentration, irritability
  • Chronic narcotic and corticosteroids use

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Citation

Stephens, Mark B., et al., editors. "Testosterone Deficiency." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2019. 5minute, www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116889/all/Testosterone_Deficiency.
Testosterone Deficiency. In: Stephens MB, Golding J, Baldor RA, et al, eds. 5-Minute Clinical Consult. 27th ed. Wolters Kluwer; 2019. https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116889/all/Testosterone_Deficiency. Accessed May 26, 2019.
Testosterone Deficiency. (2019). In Stephens, M. B., Golding, J., Baldor, R. A., & Domino, F. J. (Eds.), 5-Minute Clinical Consult. Available from https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116889/all/Testosterone_Deficiency
Testosterone Deficiency [Internet]. In: Stephens MB, Golding J, Baldor RA, Domino FJ, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2019. [cited 2019 May 26]. Available from: https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116889/all/Testosterone_Deficiency.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Testosterone Deficiency ID - 116889 ED - Stephens,Mark B, ED - Golding,Jeremy, ED - Baldor,Robert A, ED - Domino,Frank J, BT - 5-Minute Clinical Consult, Updating UR - https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116889/all/Testosterone_Deficiency PB - Wolters Kluwer ET - 27 DB - 5minute DP - Unbound Medicine ER -