Growth hormone deficiency is also referred to as pituitary dwarfism. It is a condition that is caused by low amounts of growth hormones in the body. Children with growth hormone deficiency have normal body proportions with an abnormally short stature. Low growth hormone deficiency can manifest in birth or later life stages.
Where does the growth hormone come from?
Growth hormone is a protein produced by the pituitary gland which is located in the brain right behind the eyes. Apart from the growth hormone, the pituitary gland produces other hormones such as luteinizing hormone, prolactin, and follicle-stimulating hormone, vasopressin, thyroid-stimulating hormone, adrenocorticotropic hormone, and oxytocin.
The hypothalamus which is a part of the brain above the pituitary gland produces two hormones namely somatostatin and growth hormone-releasing hormone that controls the amount of growth hormone released by the pituitary gland.
The amount of growth hormone released by the pituitary gland changes within our lifetime. It increases in childhood during puberty and decreases as we get older. The growth hormone is released into the bloodstream which then stimulates the liver to produce another hormone called IGF-I (Insulin Growth Factor-I).
IGF-I is used by medical practitioners as a screen test to check for growth hormone deficiency or conditions like gigantism or acromegaly. The growth hormone and insulin growth factor-1 act in many body tissues like the muscles, brain, fat, and bones.
What is the function of the growth hormone?
The main function of the growth hormone is the regulation of body fluids, body composition, bone and muscle growth, mental function, and heart function. Growth hormone deficiency in children can be easily identified with poor growth hormone. In adults, it can be hard to identify since they have achieved adult height after the fusing of their bones preventing more growth.
The deficiency in growth hormone in adults can be understood via the assessment of body composition. These important body parts lack proper nurturing in growth hormone deficiency leading to abnormal metabolism.
This deficiency causes fat to be deposited more easily especially around the abdomen. There is also less muscle strength and a decreased ability to exercise. Bones become weaker due to reduced bone mineral density which increases the risk of osteoporosis as we age.
Adults who have low growth hormone experience adverse effects on glucose and cholesterol metabolism. This leads to high blood cholesterol. Good cholesterol is needed to be as high as possible. Good cholesterol (HDL cholesterol) becomes lower as a result of growth hormone deficiency. Due to higher fat content in the abdomen the risk of developing diabetes and cardiovascular diseases increases as we get older.
What are the symptoms of growth hormone deficiency in adults?
The common symptoms of growth hormone deficiency in adults are central weight gain, fatigue, dry skin, and lack of feeling one’s self. Most people notice a decreased level of physical exercise endurance and their level of physical energy. Some may develop depression or anxiety and avoid social contact with family and friends.
Causes of growth hormone deficiency in adults.
For children, growth hormone deficiency occurs due to the hypothalamus failing to function and not producing enough growth hormone-releasing hormone to stimulate the pituitary gland to release the growth hormone. MRI might not reveal pituitary damage in children with hormone growth deficiency. This deficiency may persist into adulthood.
Adults who develop growth hormone deficiency do so because of some damage to the hypothalamus or pituitary gland. This leads to the pituitary gland being unable to release the adequate growth hormone required by the body. The most common damage to the hypothalamus and pituitary gland is a tumor in the pituitary gland and hypothalamus. The tumor, surgery, or radiation therapy can cause adult growth hormone deficiency.
Some recently discovered conditions that can cause growth hormone deficiency include: bleeding in the base of the brain, head injury, stroke, and brain infections like meningitis.
Methods used to detect and confirm growth hormone deficiency.
The doctor will conduct several tests to establish if you have a hormone growth deficiency or not. Measuring hormone growth deficiency in the blood is hard due to the irregular growth hormone levels in the blood during the day and can be low in normal people.
The doctor will do a stimulation test that will stimulate growth hormone secretion from your pituitary gland to the bloodstream. Through measuring your blood at intervals after stimulation of the pituitary gland your response to the stimulus is arrived at by recording several growth hormone levels in the blood.
For normal individuals, there is a rise in the growth hormone in the blood while in deficient individuals there is little or no growth hormone rise in the blood. The medications used to stimulate the production of growth hormone include glucagon and insulin.
The insulin tolerance test is viewed as the reference standard growth hormone stimulation test but it is tedious and can cause severe hyperglycemia. It is also contraindicated in specific patients. Glucagon test is the alternative test if insulin test cannot be conducted on specific patients.
Administration of growth therapy.
Growth hormone is administered daily by injection into the fat tissue. Most individuals inject it into the fat on the lower abdomen. Syringes and needles are used similar to that of diabetic patients. Recently there are easy-to-use pen delivery devices to administer the growth hormone.
Some devices hide the needle and you cannot see it when administering the injection. The doctor will prescribe the appropriate dosage. The dosage may change depending on your response. Growth hormone is not administered orally since it is digested in the stomach before entering the bloodstream.
Symptoms of taking too much growth hormone.
Too much growth hormone administration manifests through joint aches, swelling in the ankles, a rise in blood pressure and glucose levels, and pain in your hands. Immediately notify your doctor if these symptoms occur. These side effects go away if the treatment is temporarily stopped or the dosage is reduced.
Just as children, adults require the growth hormone all their lives. Without growth hormone, there are increased risks of abnormal body composition, diabetes and cardiovascular diseases risk, central fat disposition risk, the risk of low bone mineral density, reduced physical energy, and psychological well-being. Growth hormone replacement in adults often improves but not all symptoms associated with it hence should be continued for a long period.