Hypogonadism can be divided into three forms depending on the causes. In primary hypogonadism, the cause is found directly in the gonads. Although the higher-level hormonal centers stimulate the ovaries or testicles, these produce too few hormones. A typical congenital primary disorder in men is Klinefelter syndrome. People with this disorder have an additional X chromosome instead of the usual XY chromosome set in men.
Primary hypogonadism also occurs in women who suffer from Turner syndrome. Instead of two sex chromosomes (XX), they only have one functional X chromosome. In men, testicular tumors or injuries in the genital area can also lead to reduced hormone production. In women, ovarian cancer and/or inflammation in this area can be a possible cause.
Secondary hypogonadism, on the other hand, is caused by a disorder of the pituitary gland, which acts as a superordinate hormonal center in the brain. It releases follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These so-called releasing hormones stimulate the gonads to produce the sex hormones. If there is a lack of releasing hormones, the ovaries and testicles produce too little testosterone or oestrogen and progesterone.
Pituitary adenoma is a typical disease in which secondary hypogonadism can occur. It is a rare, benign tumor in the head. Secondary hypogonadism can also occur in congenital disorders, such as Kallmann syndrome, or direct damage to the anterior pituitary gland. The rarest form of hypogonadism, tertiary hypogonadism, occurs when the cause can be found at the level of the hypothalamus.
The hypothalamus is a part of the diencephalon that, like the pituitary gland, releases releasing hormones. However, these do not directly stimulate the gonads, but the pituitary gland to release FSH and LH. A lack of these pituitary releasing hormones results in reduced gonadal activity and a reduced release of sex hormones.
The symptoms are extremely varied and are by no means limited to the sexual sphere. If there is already a lack of testosterone in childhood, puberty does not occur. This is also referred to as eunuchism. Both the primary and secondary sexual characteristics remain behind in development. Those affected therefore have a small testicular volume and an underdeveloped penis. Furthermore, body hair tends to be sparse. The following symptoms can occur in adulthood:
- Decrease in libido
- Loss of armpit and pubic hair
- Reduced beard growth
- Decrease in body size
- Spontaneous fractures due to reduced bone density
- Loss of muscle mass and strength
In women,
the main
symptoms are
abnormalities in the menstrual cycle. If the hormone disorder already exists before puberty, the affected girls never get their period. This is referred to as
primary amenorrhea. Menstruation also fails to occur in adulthood
(secondary amenorrhea). As there is no ovulation, women with hypogonadism are
infertile.
In a detailed medical history, the treating doctor can ask about all symptoms using special questionnaires. There are often already indications of hypogonadism here. The physical examination also reveals findings associated with hypogonadism, such as underdeveloped genitals or reduced body hair. However, laboratory chemical tests are essential for a reliable diagnosis.
The doctor determines the levels of the sex hormones testosterone, oestrogen, progesterone, LH, FSH and the concentration of sex hormone binding globulins (SHBG). If secondary or tertiary hypogonadism is suspected, the organ-specific releasing hormones must also be tested. A low hormone level should always be confirmed by at least a second measurement, as a temporary decrease can also be caused by other acute illnesses.
If there is a specific suspicion, imaging procedures such as sonography (ultrasound) can also be helpful. This allows the gonads to be visualized and assessed structurally.
The treatment depends on the cause of the hormonal disorder. Tumors, for example, are treated with chemotherapy or radiotherapy. However, causal treatment is not always possible. To alleviate the symptoms, patients are then given hormone preparations in the form of tablets, creams, depot injections or patches.
As hormone replacement therapy carries risks, possible contraindications must be ruled out before treatment. These include, for example, hormone-dependent tumors, hypersensitivity to artificial hormones or other ingredients of the preparations as well as previous or existing cancer of the liver.
The prognosis depends primarily on the cause. If it can be treated well and those affected regularly take sex hormones,
sexual characteristics can usually be restored. Possible secondary diseases that can occur due to the hormone deficiency can also be prevented in this way.
