Growth hormone deficiency in adulthood

What is growth hormone deficiency in adulthood?

Growth hormone deficiency in adulthood is one of the rare diseases. The human organism produces growth hormone (STH = somatotropic hormone or GH = growth hormone) not only during childhood and adolescence, but throughout life. It fulfills a whole range of important tasks:

• During adolescence, it controls the length development of the body.
• It regulates the proportion of fat and muscle tissue.
• It is involved in the regulation of blood sugar levels.
• It determines the water content of the cells.
• GH is also involved in other metabolic processes.

The pituitary gland produces growth hormone in a 24-hour rhythm. During the day it only produces small amounts, at night the hormone level is at its highest. It releases the hormone into the blood, through which it reaches the target organs. GH influences body functions directly or indirectly by releasing growth factors, the most important of which is IGF1 (insulin-like growth factor 1), from the liver. In addition to its important role in body growth, this hormone influences many metabolic processes, such as fat, protein and blood sugar metabolism, which indicates that it also plays an important role in adulthood.

Growth hormone deficiency in adulthood: causes and risk factors

The causes of growth hormone deficiency in adulthood are varied, although there are three groups:

• The growth hormone deficit has existed since childhood. The cause may be a genetically determined underdevelopment of the pituitary gland or a head injury, for example due to a difficult birth (breech presentation). It also includes the treatment of childhood diseases that lead to a violation of hormone production (similar to adults)
• Growth hormone deficiency is caused by an illness or injury that occurred in adulthood. Possible diseases include: benign tumors of the pituitary gland, such as adenomas or craniopharyngiomas, injuries caused by an accident, surgery or radiation.
• Growth hormone deficiency is idiopathic, i.e. the cause is unclear.

There is not necessarily a complete failure (insufficiency) of the entire pituitary gland. It still produces hormones to some extent, but not in sufficient quantities.

Symptoms: Weight gain and bad mood

If you have a growth hormone deficiency in adulthood, you may show the following symptoms:

• They produce more abdominal fat but have a lower proportion of muscle mass.
• Your blood lipid levels are elevated (hyperlipidemia).
• Your blood sugar level is low (hypoglycemia).
• You lack driving force.
• They are prone to depression.
• They suffer from a poor general sense of well-being and a bad mood.
• Your bone density is reduced, which increases your risk of osteoporosis.

Growth hormone deficiency in adulthood: diagnosis by us

It is not easy to diagnose growth hormone deficiency in adulthood, as the symptoms caused are non-specific. A leading symptom – such as insufficient length growth in childhood – is missing. As a rule, endocrinologists examine people for the deficiency who have a disease in the area of the pituitary gland, who have had surgery or radiation or who have suffered a traumatic brain injury.

It is also difficult to detect a growth hormone deficiency because the blood level fluctuates considerably throughout the day. In addition, a “normal” growth hormone level depends on whether and how much overweight the person concerned is, as well as whether other diseases such as blood sugar disorders or severe kidney or liver dysfunction are present.

The insulin hypoglycemia test (IHT): The insulin tolerance test (IHT) is the standard procedure for detecting a GH deficiency. To do this, we administer insulin via the vein to induce hypoglycemia, which stimulates the release of growth hormone. Over the next two hours, the level of growth hormone in your blood is measured repeatedly. If it does not rise accordingly, this is a sign of a hormone deficiency.

The GHRH-arginine test: Alternatively, the endocrinologist can administer Growth Hormone Releasing Hormone (GHRH) intravenously. The growth hormone level in the blood is then measured regularly. Here too, body weight influences which values are considered to be within the norm.

Imaging procedures such as CT and MRI are also used to detect changes in the brain and pituitary gland.

In the Clinic for Endocrinology, Diabetology and Clinical Nutrition at the USZ, these tests are carried out regularly on an outpatient basis in our function room.

Growth hormone deficiency: prevention, early detection, prognosis

They cannot prevent a growth hormone deficiency in adulthood. Early detection is difficult because of the unspecific symptoms.

The prognosis for treatment is good. In most cases, the therapy can improve the quality of life. However, the patient’s willingness to reliably administer the hormone on a daily basis is important.

Growth hormone deficiency: treatment with hormones

Adults with a GH deficiency inject a dose of growth hormone into the subcutaneous fatty tissue once a day as therapy. As a rule, you use a so-called pen, which is also used by diabetics. In the near future, it will also be possible to administer depot injections and thus reduce administration to once a week.

Patients who benefit most from the therapy are usually those who have very low hormone levels and very severe symptoms. If there is no improvement within six to twelve months despite the therapy, for example in quality of life or body fat distribution, you should discuss with your doctor whether you should stop the therapy.

If the cause of the growth hormone deficiency is a tumor on the pituitary gland, surgery may be necessary.