What is hypogonadism?
Hypogonadism is a condition in which the testicles are not working the way they should.
In an adult, the testicles have two main functions: to make testosterone (the male hormone) and sperm. These activities are controlled by a part of the brain called the pituitary. The pituitary sends signals (called gonadotropins) to the testicles that, under normal conditions, cause the testicles to produce sperm and testosterone.
The pituitary signals can change based on the feedback signals that the brain receives from the testicle. Hypogonadism can therefore be divided into two main categories:
- A problem with the signals from the brain to the testicles
- A problem within the testicle itself
These categories are important because they may influence the way that hypogonadism is treated, and play a role in the results.
What are the types of hypogonadism?
Testicular failure (primary hypogonadism)
Testicular failure occurs when the brain is signaling the testicle to make testosterone and sperm, but the testicles are not responding correctly. As a result, the brain increases the amount of the gonadotropins signals, which causes a higher-than-normal level of these signals in the blood. For this reason, this condition is also referred to as hypergonadotropic hypogonadism. This is the most common category of hypogonadism.
Secondary hypogonadism (also called hypogonadotropic hypogonadism) occurs when the brain fails to signal the testicles properly. In men who have secondary hypogonadism, the testosterone levels may be very low, and sperm are usually missing from the semen. Some boys are born with this condition. In most cases, it is discovered when a boy fails to go through puberty.
What are the causes of primary hypogonadism?
Causes of primary hypogonadism include:
- Congenital (the person is born with the condition): certain conditions, including Klinefelter’s syndrome, cryptorchidism, varicocele, and myotonic dystrophy; gene mutation; chromosomal abnormalities
- Acquired: infections; radiation; environmental toxins; alkylating agents; ketoconazole; glucocorticoids; testosterone and/or anabolic steroid abuse; testicular torsion (twisting of the spermatic cord inside the testicle); autoimmune damage; chronic systemic illness
- Idiopathic: unknown cause
What are the causes of secondary hypogonadism?
Causes of secondary hypogonadism include:
- Congenital (the person is born with the condition): certain conditions, including Kallman’s syndrome, Prader Willi syndrome; idiopathic (cause unknown)
- Acquired: hyperprolactinemia; diabetes mellitus; obesity; steroid treatment; critical illness; chronic opiate use; anorexia nervosa; idiopathic (cause unknown)
- Damage to pituitary: benign (non-cancerous) tumors and cysts; malignancy (cancer); infections; trauma (including surgery in certain areas of the brain); radiation; pituitary bleeding
What are the symptoms of hypogonadism?
Low testosterone: Hypogonadism may be diagnosed when a man has symptoms of low testosterone, including low energy, fatigue, and a lower sexual drive.
Patients with secondary hypogonadism are usually diagnosed during their teen years because they have not started puberty. These patients may not develop the body type, muscle build, or hair pattern seen in adult males. Some men will also have a poor sense of smell.
Infertility: Hypogonadism may be diagnosed when a man has a problem with fertility (cannot father a child) and is found to have no sperm or only a very low number of sperm in the semen.