Topic Name

A	B	C	D	E	F	G	H	I
J	K	L	M	N	O	P	Q	R
S	T	U	V	W	X	Y	Z	#

Disease Categories > Endocrine Disease

Font

Hypogonadism, Male

Hypogonadism is one of the most common endocrine disorders in men, and is characterized by low serum testosterone levels with clinical signs and symptoms of the disease.

Epidemiology

Prevalence
- Estimated 4-5 million men in U.S. have hypogonadism
- 20% of men 60 or older have hypogonadism
- Frequency increases with obesity, type II diabetes mellitus, aging

Etiologies

Primary (pathology in testes)
- Autoimmune orchitis
- Chemotherapy
- Cryptorchidism
- Dysgenetic testes
- Klinefelter syndrome
- Mumps orchitis
- Myotonic dystrophy
- Orchiectomy
- Radiation
Secondary (pathology in pituitary)
- Alcohol abuse
- Cushing syndrome
- Drugs (corticosteroids, opiates)
- Hyperprolactinemia
- Iron overload
- Pituitary lesions
- Severe chronic illness (cancer, chronic liver disease, chronic renal disease, rheumatoid arthritis, diabetes melitis, obesity)
- Other genetic mutations
Tertiary (pathology in hypothalamus)
- Kallman syndrome
- Prader-Willi syndrome
Age-related hypogonadism (pathology in testes and hypothalamus)

Pathophysiology

Gonadotropin-releasing hormone (GnRH) is secreted from the hypothalamus
GnRH stimulates the release of leuteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary
LH promotes secretion of testosterone from Leydig cells
FSH stimulates spermatogenesis and inhibin B production from Sertoli cells inhibits FSH
2% of circulating testosterone is free; 98% is bound
- 60% bound to albumin
- 40% bound to sex hormone binding globulin
Bioavailable testosterone = free testosterone plus albumin bound testosterone
Substantial alterations in sex hormone binding globulin affect total testosterone level
- Free testosterone and bioavailable testosterone levels more accurately reflect bioactive testosterone under these circumstances

Clinical Presentation

Manifestations depend on the age of onset of hypogonadism
Pubertal hypogonadism
- Eunuchoidal body habitus
- Gynecomastia
- Small testes
- Lack of secondary sexual characteristics
Postpubertal hypogonadism
Weakness
- Decreased libido
- Depressed mood
- Impotence
- Normal penile size
- Low bone mineral density
- Gynecomastia
- Muscle loss
- Abdominal adiposity

Diagnosis

Indications for testing – signs and symptoms of hypogonadism
Laboratory testing
- Screen with serum testosterone concentration (preferably between 8-10 am)
  - For children, use mass spectrometry assay
  - For adult males, use radioimmunoassay (mass spectrometry not necessary) – <300 ng/dL suggests hypogonadism
- If total testosterone is abnormal, may consider testing for free testosterone concentrations – helpful in determining bioavailable testosterone
- FSH/LH to differentiate between primary and secondary etiologies
  - Primary – FSH and LH are elevated
Imaging
- If testosterone <150 ng/dL – consider MRI for pituitary imaging and if LH is normal to low prolactin may be increased

Differential Diagnosis

Pituitary lesions
Dementia
Hypothyroidism adrenal tumor
Depression
Diabetes mellitis
Hemochromatosis
Cystic fibrosis

Treatment

Androgen replacement

Indications for Ordering

Tests generally appear in the order most useful for common clinical situations
Click on number for test-specific information in the ARUP Laboratory Test Directory

Test Name and Number	Recommended Use	Limitations
Testosterone, Adult Male 0070130 Method: Electrochemiluminescent Immunoassay	Diagnose and monitor hypogonadism	This test is not recommended for females or children
Luteinizing Hormone/Follicle Stimulating Hormone 0070193 Method: Electrochemiluminescent Immunoassay	Diagnose and monitor hypogonadism
Testosterone, Bioavailable & Sex Hormone Binding Globulin (Includes Total Testosterone), Adult Male 0070102 Method: Electrochemiluminescent Immunoassay The concentrations of free and bioavailable testosterone are derived from mathematical expressions based on constants for the binding of testosterone to albumin and/or sex hormone binding globulin.	Diagnose and monitor hypogonadism Use for patients with suspected plasma protein abnormalities	This test is not recommended for females or children
Testosterone Free, Females or Children 0081059 Method: Tandem Mass Spectrometry The concentration of free testosterone is derived from a mathematical expression based on the constant for the binding of testosterone to sex hormone binding globulin.	Diagnose and monitor hypogonadism
Testosterone Free, Adult Male 0070111 Method: Electrochemiluminescent Immunoassay The concentration of free testosterone is derived from a mathematical expression based on the constant for the binding of testosterone to sex hormone binding globulin.	Diagnose and monitor hypogonadism	Not recommended for testing children

Additional Tests Available

Click on number for test-specific information in the ARUP Laboratory Test Directory

Test Name and Number	Comments
Testosterone, Free & Total (Includes Sex Hormone Binding Globulin), Adult Male 0070109 Method: Electrochemiluminescent Immunoassay The concentration of free testosterone is derived from a mathematical expression based on the constant for the binding of testosterone to sex hormone binding globulin.
Testosterone, Bioavailable & Sex Hormone Binding Globulin (Includes Total Testosterone), Females or Children 0081057 Method: High Performance Liquid Chromatography/Tandem Mass Spectrometry The concentrations of free and bioavailable testosterone are derived from mathematical expressions based on constants for the binding of testosterone to albumin and/or sex hormone binding globulin.	This test is suggested for children due to an improved sensitivity of testosterone by LC-MS/MS
Testosterone Free, Females or Children 0081059 Method: Tandem Mass Spectrometry The concentration of free testosterone is derived from a mathematical expression based on the constant for the binding of testosterone to sex hormone binding globulin.
Sex Hormone Binding Globulin 0099375 Method: Electrochemiluminescent Immunoassay
Testosterone, Urine 0070716 Method: Chemiluminescent Immunoassay