When GH deficiency is diagnosed and treated early, some children can grow several inches in the first year of treatment. Others grow less and more slowly, but still benefit from treatment. If GH levels don't decrease to a certain level during a GH suppression test, it may mean your child has gigantism or you have acromegaly. Gigantism and acromegaly are most often caused by a tumor in pituitary gland, a small organ in the base of the brain that controls many functions, including growth.
If the disorders were not caused by a tumor, you or your child may need more tests. Learn more about laboratory tests, references ranges, understanding results. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. Growth Hormone Tests.
What are growth hormone tests? What are they used for? In children, GH is essential for normal growth and development. A GH deficiency can cause a child to grow more slowly and be much shorter than children of the same age. In adults, GH deficiency can lead to low bone density and reduced muscle mass. This is a rare childhood disorder that causes the body to produce too much GH.
Children with gigantism are very tall for their age and have large hands and feet. This disorder, which affects adults, causes the body to produce too much growth hormone. Adults with acromegaly have thicker than normal bones and enlarged hands, feet, and facial features. The tests may also be used if other tests show a problem with the pituitary gland.
Why do I need a growth hormone test? Your provider may order a GH test if you or your child has symptoms of a GH disorder. Symptoms of GH deficiency in children include: Slowed growth rate compared with children of the same age Shorter height, arms, and legs, and lower weight than children of the same age Small penis in males Delayed puberty Adults with GH deficiency may have symptoms such as fatigue and decreased bone density and muscle mass.
Symptoms of GH excess gigantism in children include: Excessive growth compared with children of the same age Overly large head Larger than normal hands and feet Mild to moderate obesity Symptoms of GH excess acromegaly in adults include: Deep, husky voice Larger than normal facial features such as lips, nose, and tongue Excessive sweating and body odor Thickening of bones Coarse, oily skin Irregular menstrual cycles in women Erectile dysfunction in men.
What happens during a growth hormone test? A GH stimulation test is used to check for a GH deficiency. Endocrinology: Adult and Pediatric. Philadelphia, PA: Elsevier Saunders; chap Evaluation of endocrine function. St Louis, MO: Elsevier; chap In: Kliegman RM, St. Nelson Textbook of Pediatrics. Philadelphia, PA: Elsevier; chap Reviewed by: Liora C. Review provided by VeriMed Healthcare Network.
Editorial team. How the Test is Performed Blood is drawn several times. The procedure is done the following way: An IV is usually placed in a vein, most often the inside of the elbow or the back of the hand.
The site is first cleaned with germ-killing medicine antiseptic. The first sample is drawn early in the morning. Medicine is given through the vein. This medicine stimulates the pituitary gland to release GH. Several medicines are available. The health care provider will decide which medicine is best.
Additional blood samples are drawn over the next few hours. Those with excess GH may also have thickening of facial features, general weakness, delayed puberty and headaches. Although GH is not as active in adults, it does play a role in regulating bone density, muscle mass and lipid metabolism.
Deficiencies can lead to decreased bone densities, less muscle mass and altered lipid levels. Excess GH in adults can lead to condition called acromegaly , marked by bone thickening. Although symptoms such as skin thickening, sweating, fatigue, headaches and joint pain can be subtle at first, increased GH levels can lead to enlarged hands and feet, enlarged facial bones, carpal tunnel syndrome and abnormally enlarged internal organs. If untreated, acromegaly and gigantism in children can lead to complications such as type 2 diabetes , increased cardiovascular disease risk, high blood pressure , arthritis , and in general, a decreased life span.
Usually GH suppression or stimulation testing is done to diagnose GH abnormalities. Since growth hormone is released by the pituitary in bursts throughout the day, random measurement of GH levels are not usually clinically useful.
After fasting for 10 to 12 hours usually overnight , a blood sample is drawn from a vein in the patient's arm. Then, under medical supervision, the patient is given an oral glucose load solution to suppress GH or given insulin or arginie or other substances through a needle in their vein to stimulate GH production. Blood samples are then drawn at timed intervals to monitor the effect of the substance given.
GH tests are run on each sample collected to monitor the change in levels of growth hormone over time. Sometimes, a single sample of blood is drawn following a fast or after a period of strenuous exercise. Follow the instructions that you are given by your doctor, for example to fast, in order to prepare for this test as GH levels increase sharply hours after eating and within 1 hour after onset of sleep. Children and early adolescents who are being tested for GH deficiency should be prepared for treatment with sex steroids for a few days prior to testing.
Such treatment reduces the number of falsely low GH responses to stimulation. The health practitioner who is orderin gthe GH testing should provide the child's parents with a prescription for such medications. Some healthcare providers will also prescribe propanolol prior to testing to reduce the number of falsely low GH responses to stimulation. GH testing may be used to test for abnormal pituitary function and to help diagnose the condition causing the abnormality, its severity, and the complications that have arisen because of it.
For example, hypothyroidism must be treated prior to testing for GH deficiency in childre; otherwise, a falsely low GH result may be seen. IGF-1 Insulin-like growth factor—1 is often measured before or during GH provocation testing and can be used by itself or with GH as a monitoring tool.
Produced in the liver, IGF-1 mirrors GH excesses and deficiencies, but its level is stable throughout the day, making it a useful indicator of average GH levels. GH testing is usually ordered on those with symptoms of growth hormone abnormalities or as a follow-up to other abnormal hormone test results.
It is not recommended for general screening. GH tests may be ordered to help evaluate pituitary function:. Periodic GH measurements may also be performed on children who have had radiation treatment of the central nervous system or whole body irradiation prior to stem cell transplants. This is common in acute lymphoblastic leukaemia ALL , where irradiation of the brain can affect the hypothalamus and pituitary gland, thus affecting growth.
Growth hormone tests help identify excess and diminished GH production and give your doctor information about the severity of your condition and are part of the diagnostic work-up to find the reason for abnormal hormone production. GH stimulation testing is ordered when a child has symptoms of growth hormone deficiency GHD , such as when:. Once GHD is diagnosed, your doctor may use stimulation testing to confirm the diagnosis, along with IGF-1 to monitor the effectiveness of GH replacement if indicated , and as a child reaches adulthood to see if continued supplementation is necessary.
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