Below are some frequently asked questions we hear from patients.
Click on any for the answer.
The term empty sella is actually a misnomer, for the sella is not empty, it is usually filled with cerebrospinal fluid. Empty sella is one of the more common incidental findings on MRI's and CT scans of the head performed for other reasons. There are two main causes of an empty sella. First, there can be a congenital large opening in the tough membrane that is stretched over the top of the socket (sella) for the pituitary gland. This opening allows the transmission of spinal fluid pressure into the sella and consequent flattening of the pituitary gland. Second, patients can have inflammatory disorders (lymphocytic hypophysitis, sarcoidosis) or tumors that degenerate creating a void within the sella. The void is then filled with spinal fluid as the more flexible membranes surrounding the brain herniate into the sella. Patients with empty sella usually have normal pituitary function but some may have one or more pituitary hormone deficiencies. An occasional patient has a coexisting empty sella and a pituitary tumor. Patients who have an empty sella should seek advice from an endocrinologist in order to determine whether they have evidence of over or under production of pituitary hormones and whether there is some underlying disease process that needs medical attention.
Sheehan's Syndrome is hypopituitarism due to pituitary infarction that occurs at the time of obstetrical hemorrhage and consequent low blood pressure. During a pregnancy, the pituitary doubles in size. This doubling is due to an increase in a number of prolactin-producing cells. The pituitary is much more metabolically active and demands more blood supply. Any insult that threatens the blood pressure, such as bleeding during childbirth, can result in decreased pituitary function. Hemorrhage in the pituitary can also occur. Many patients are unable to breastfeed their children in the postpartum because prolactin levels fall. Other Sheehan's Syndrome patients fail to regain their periods after childbirth. Some patients develop symptoms and signs of pituitary dysfunction immediately while others do not come to medical attention for years because their pituitary function is partially preserved.
The decision to take growth hormone is an important one and should be based on an individual case-by-case assessment of the potential risks and benefits. Many patients who have hypopituitarism and are treated with cortisol, thyroid hormone, and sex hormones are also growth hormone deficient. Growth hormone therapy for adults has been approved by the US Food and Drug Administration only for individuals with a history of pituitary disease. The symptoms and signs of growth hormone deficiency are nonspecific. Many of them take years to develop after the insult that leads to hypopituitarism. Most authorities would agree that growth hormone deficiency is characterized by altered composition of body tissues with a predominant increased fat content and decreased amount of muscle tissue, and an abnormal lipid profile characterized by a high bad cholesterol, osteoporosis and vague psychosocial dysfunction including decreased motivation, social interaction and poor self esteem. Growth hormone replacement therapy alters body composition so that there is more lean muscle and less fat mass, can lead to dramatic increases in bone density, can result in a more favorable lipid profile, can result in better exercise tolerance, and can improve social functioning and a patient's sense of well being. At the present time, growth hormone replacement in adults is accomplished by a single daily subcutaneous injection. Growth hormone doses are adjusted based on blood levels of IGF-1, a protein made by the liver in response to growth hormone. The most common side effects are swelling in the hands and feet and pains in joints and muscles. Side effects of growth hormone replacement are rare because the intent of therapy is to simply replace growth hormone to normal levels.
Recombinant growth hormone is currently the treatment of choice for growth hormone deficiency in adults and children. Recombinant growth hormone is a synthetic compound produced in a laboratory identical to human growth hormone. Recombinant growth hormone does not contain any human tissue. The technology takes advantage of the machinery found in bacteria to produce the growth hormone protein. There is no transmission of bacteria to humans or risk of contamination.
Growth hormone is secreted in a pulsatile fashion from the anterior pituitary gland by a feedback mechanism from the hypothalamus. Both an inhibitory peptide, Growth hormone release - inhibiting hormone, and a stimulatory peptide, growth hormone - releasing hormone, play an important role in its secretion. Physiological factors affecting the secretion of growth hormone include: age, exercise, nutritional status, sleep, level of stress and development growth. More specifically, growth hormone secretion is stimulated by exercise, sleep and fasting, while growth hormone is decreased by food intake, obesity and aging.
Signs and Symptoms of growth hormone deficiency include: decreased bone mineral density, abnormal body composition (i.e. increased body fat & decreased muscle mass), emotional disturbances (i.e. social isolation, lability, impaired memory and difficulties with sex life,) altered lipid metabolism (i.e. increased LDL, decreased HDL, elevated total cholesterol and elevated triglycerides), and exercise intolerance.
Since growth hormone is secreted in a pulsatile manner and fluctuates significantly in a 24 hour period, random growth hormone and IGF-1 levels are of little diagnostic value. Both of these biochemical studies can therefore only be used as screening tests and to monitor the effectiveness of therapy once a patient has begun treatment. The preferred method of diagnosis is a stimulation test measuring serial growth hormone levels in response to certain pharmacological agents. Some of the more popular stimulating agents include insulin, arginine, levodopa, glucogon and clonidine. In adults, a peak growth hormone response of less than or equal to 5ng/ml in response to stimulation is diagnostic of growth hormone deficiency. In children, a peak stimulated growth hormone response less than or equal to 10ng/ml on two consecutive tests is diagnostic of pediatric growth hormone deficiency. For more specific information on growth hormone deficiency diagnostic test see website.
Growth hormone is important in adults as it is involved in several metabolic processes in addition to linear growth during childhood. Other actions of growth hormone include stimulation of lipolysis, bone turnover, synthesis of proteins that have multiple effects on tissues and organs (i.e. kidney, heart, liver intestines.) Also, growth hormone effects the metabolism in muscle and fatty tissue resulting in an increase in fat mass and a decrease in muscle mass. Without sufficient production of endogenous growth hormone, bodily functions are compromised.
Common side effects of growth hormone replacement include arthalgias, fluid retention, carpel tunnel syndrome and muscle pain. Less frequent adverse reactions include: hyperglycemia (more prevalent among individuals susceptible to type II diabetes), hypertension, acne, back pain, rhinitis and headaches.
Growth hormone deficiency can be congenital or acquired and either present in childhood or as an adult. The most common causes of growth hormone deficiency include: a deficiency of GHRH, tumors (i.e. hypothalmus, pituitary and intracranial), cranial radiation, hypopituitarism (congenital or post transphenoidal surgery.) Other causes rarely identified in clinical practice include: head injury, infection, severe psychological deprivation, hydrocephalus and vascular abnormalities.
Treatment with growth hormone replacement must be individualized and monitored by a physician. If the primary objective were to obtain maximal linear height than it would be reasonable to discontinue therapy once this goal has been achieved. Many patients have decided to continue with therapy after the ephyphisis have closed to take advantage of its additional effects. Benefits of growth hormone replacement in adults include: increased bone density, improved lipid metabolism, increased muscle mass, decreased fat mass, increased exercise capacity and improved quality of life.
Growth hormone replacement should not be used if there is any evidence of neoplastic activity. Data suggests that growth hormone may stimulate tumor development therefore it is imperative that there is no disease activity prior to initiating treatment. If any tumor re-growth is identified during the course of treatment, it is recommended that therapy be discontinued immediately. Periodic MRI's are recommended throughout the course of therapy to prevent this potential effect of growth hormone replacement. Growth hormone replacement has not been recommended for use during pregnancy. To date, there have not been any well controlled or adequate studies in pregnant females. Animal reproductive studies in rats demonstrated lengthened estrus cycles, decreased sperm motility and a slight increase in fetal deaths using supraphysiological doses of replacement. There was however no evidence of teratogenicity or adverse effects associated with lactation. Insufficient data exists concerning the secretion of growth hormone replacement in breast milk. Since many drugs are secreted in breast milk, it is recommended that nursing mothers refrain from using growth hormone replacement until further research has been conducted. Growth hormone replacement may interfere with the clearance of other drugs metabolized by CP450 liver enzymes (i.e. anticonvulsants, cylcosporine, corticosteroids and sex steroids.) Careful monitoring is recommended for patients treated with these medications. Dosage adjustments may be required therefore close follow up is essential.
The effects of growth hormone replacement occurs gradually, therefore it is important to be patient and comply with the prescribed therapy. Usually it takes a few months to notice an improvement in body composition and overall wellbeing while an increase in energy and exercise capacity is more immediate.
Medical follow-up is recommended to monitor treatment throughout the course of therapy. The starting dose of growth hormone replacement is individualized and gradually increased in response to clinical effect and tolerability. Periodic visits are necessary to assess clinical response, perform biochemical studies to aid in dosage titration and evaluate overall effectiveness of therapy. Annual MRI's are recommended to rule out neoplastic activity. Also, an annual lipid profile has also been suggested to monitor changes in body composition. Once a patient's condition has stabilized follow-up visits may be less frequent (i.e. every six to twelve months.)
Growth hormone replacement used to reverse the aging process is controversial and not supported by the American Medical Association. The Food and Drug Administration has not acknowledged its use to reverse the aging process as there has not been adequate or well controlled studies performed.
Yes, it can be dangerous to take growth hormone replacement when it's not medically necessary. Acromegalic features may develop including: overgrowth of maxillary and mandibular bones, frontal bossing, deepening of the voice, cardiac abnormalities (i.e. hypertension & ventricular hypertrophy,)development of skin tags, hypogonadism, diabetes mellitus, colonic polyps resulting in an increase risk of colon cancer, sleep apnea, an increase in ring and shoe size and gradual disfigurement. Growth hormone replacement must therefore be monitored by a physician preferably an endocrinologist, and administered only in the presence of deficiency.
The cost of growth hormone replacement varies from one individual to the next depending on the dose of therapy and system utilized. Growth hormone is extremely expensive, several hundred dollars per month, and not feasible to obtain without reimbursement from a third party payer.
Reimbursement requests are handled on an individual basis by third party payers for the treatment of growth hormone replacement. Most insurance companies require diagnostic (stimulation tests), and clinical evidence of growth hormone deficiency prior to approving therapy.
Most pharmaceutical companies that manufacture growth hormone replacement have reimbursement services available to patients seeking treatment. This set up eases the process in obtaining authorization both for the patient and provider.
If necessary, patients are able to start growth hormone replacement prior to obtaining authorization so they may begin therapy as soon as possible. Most companies that offer this service, do not hold the patient accountable if reimbursement is denied.
Recombinant growth hormone is supplied in several different modes to aid in administration. These include an aqueous solution, two vial system (dilutent and powder), a two chamber cartridge (pen) and a mini-quick system. A variety of systems are available to meet the different needs different patients. Growth hormone replacement (powder and dilutient) should be refrigerated at 36 degrees F to 46 degrees F (2 degrees C to 8 degrees C.) This ensures the stability of the product. The mini-quick system (unit dose), manufactured by Pharmacia & UpJohn does not require refrigeration and is therefore suitable for adults.
Growth hormone replacement is delivered directly to your home, by a distributor. If you require more supplies to administer the medication they can be contacted directly. Most distributors provide a 24 hour service to accommodate the needs of individual patients.
Growth hormone is administered by a subcutaneous injection usually given daily. Preferred sites for administration include the abdomen, thigh and buttocks. In order to prevent lipoatrophy and localized inflammation, injection sites should be rotated. The dose of growth hormone replacement is gradually increased at 4 to 8 week intervals depending on the individual needs of the patient. IGF-1 levels are monitored periodically as well as evaluation of clinical tolerability, adverse reactions and response to therapy (increased muscle mass, decreased body fat, improved lipid profile, increased energy & exercise capacity and overall improvement in wellbeing.)
Most pharmaceutical companies co-ordinate teaching to patients when necessary, so that they may begin therapy as soon as possible. Usually, nurses visit patients in the home or alternatively you may contact your physician for additional teaching.
If the dosage of growth hormone is increased or decreased it is your responsibility to notify the distributor. Your physician must inform the pharmacist responsible for supplying the drug by telephone or alternatively write a prescription acknowledging the dosage adjustment.
Support groups in the United States that provide services for patients with growth hormone deficiency include:
The Magic Foundation
1327 North Harlem Avenue
Oak Park, IL 60302
Tel # 800-3 MAGIC 3 (1-800-362-4423)
Human Growth Foundation
7777 Leesburg Pike
Falls Church, VA 22043
Pituitary Network Association
16350 Ventura Blvd., Suite 231
Encino, CA 91436
The Pituitary Clinic Division of Endocrinology - Suite 2501
TVC Vanderbilt University Medical Center
1301 22nd Ave. S
Nashville, TN 37232-5353
Questions concerning growth hormone can be directed to the pharmaceutical company supplying the product prescribed by your physician. Most companies are equipped to answer questions about reimbursement, distribution, adverse reactions and administration. If you have specific medical questions concerning growth hormone replacement contact your physician for more information.